TLDR: Find a decently fast vehicle in the fast lane, and put your car in radar cruise control. Pass only when needed. If you care to see why read along.

The Long Story

I was quite bored during a few up and downs on the I-5, so I decided to take some data on different driving behaviors. It’s well known that platooning can help reduce drag. In fact, cyclists platoon all the time to save energy. In a lot of races, you’ll see an interesting behavior where racers will actually try to avoid being the first in a platoon. (The cycling term for this technique is called drafting)

So how much does it actually help to platoon someone when you’re driving an aerodynamically sound sedan?

During the drive, I sneak up behind various type of vehicles at various speeds and gathered the energy efficiency reading from my Model 3’s energy monitor.

I also experimented with driving the car in cruise control at various constant speeds as the control sets. Here is the raw data at a glance

Let’s take a jab at digesting this data in a meaningful way. First off, let’s attempt to understand the car’s speed -> power usage relationship. We know at high speed, the car’s primary source of energy consumption is a drag. Let’s model the cruise control data points to an ideal model

According to the drag equation

Where: D is Drag force experienced by the vehicle in Newton. Cd is the drag coefficient, which is 0.23 for Model 3. ρ is the density of air, which is 1.225 kg/m^3. V is the velocity of the car in m/s. A is the incident area of the car subject to drag, for Model 3 is 2.52m^2, the rough cross-section area looking from the front of the car.

We also know that the battery’s chemical energy -> car’s kinetic energy is not perfectly efficient. We designate η as the gross efficiency from what you read on the energy monitor to the actual energy contributed to moving the car. η is the only unknown here, hence we’ll attempt to estimate η using the real-world data collected. Given our η is just an estimate and the real η is probably not a naive constant but rather a complex variable, we must limit the range of speed where a η can be estimated. The dataset works in our favor since the speed range is limited to 75-90 mph.

The Power Efficiency number can be calculated through some pretty basic math

After curve fitting, we yield η=70%. Totally reasonable considering electrical transmission loss, inverter switching loss, magnetization loss, bearing friction loss, tire loss, etc…

Now that we know the internal efficiency of the car at this speed range, we can go ahead and digest the data to generate something useful. We know that driving in the turbulent wake reduced drag, in math, this is reflected in a reduction in the drag coefficient Cd. So we will solve for Cd given all other parameters fro the collected data.

After average aggregating the table by type, we end up with this.

Now it’s become clear to us that platooning behind another vehicle generally reduces the drag coefficient by ~10%, which means the same battery will get you 10% further if you platoon.

The 10% saving may not seem like much, but let’s add up the other factors in an EV trip. As mentioned earlier, trip time, cost, and stress factory are all subjects for consideration.

The Case of the LA<->SJ Drive

Time and Cost

Consider two types of driver behavior. Driver A finds a spot in the fast lane and cruise-follow behind another car, he/she averages 80 mph for the drive. Drive B drives as fast as possible, passing cars at every opportunity, Driver B averages 85 mph for the drive.

Assumptions: They both drive Tesla Model 3 LR with a 75kWh battery; Distance from SJ to LA is 340 Miles; Drivers only drain the battery from 80%-20%(below 20% is sketchy, charging above 80% gets really slow due to the reduced voltage overhead), it takes 30 minutes of ramp-to-ramp time on a 120kW supercharger to charge from 20%-80%. Cost of electricity if $0.15/kWh. We assume the drive is overall flat for the sake of doing math.

WHAT HAPPENED HERE?

Driving super fast and pass at every opportunity actually backfired. The lack of platooning and high speed ended up costing 23% more energy per mile, which added a whole other stop to the trip to charge. It not only cots more time, but also money for the extra energy burned.

The Takeaway

Needless to say, I don’t encourage driving like an jerk and speed past people at every opportunity you have. Besides the obvious time and money penalties, driving faster and passing a lot means you are not only at elevated risk of accidents but also at elevated risks of getting a ticket. Driving fast on a stretch of cop’s favorite I-5 is a real mental stressor since you have to stay highly alert and look out polícias who will not hesitate to fine you $$$$. At the end of the day, Driver A will get to the destination excused, slower, have paid more money. Meanwhile, Driver B found a nice platoon to join, kicked back with Autopilot on, snacked on some chips and finished a whole new audiobook. Besides some minor back pain, Driver B arrives rejuvenated, enlightend, faster, safer, and cheaper.

The post Roadtrip Hack – Best Way to do a Long Drive in an EV appeared first on Dennis's Random Blab.

I’m a numbers guy, so the first thing I checked is the timeline of NZ’s COVID-19 outbreak.

Graph at https://dennisren.com/COVID19

Ardern announced that NZ would be placed under a strict lockdown on March 25th. Almost exactly 14 days later, on April 8th NZ had already flattened its curve. This isn’t some sort of coincidence. 14 days is also the upper limit of the incubation period for the coronavirus. Having effectively no more cases reported 14 days after the shutdown means that New Zealand effectively stopped the spread of the virus the moment the country was placed under quarantine.

The genre of Social Distancing what was practiced in New Zealand obviously worked, what is the US and Europe doing wrong? The answer is simple, We aren’t adhering to it strictly enough.

Take a looks at the brief comparison of the change in citizen mobility in New Zealand and the United States.

Data source: https://www.google.com/covid19/mobility/

I hope you find it obvious now the United State’s Social Distancing orders are simply not being followed by its citizens well enough. Looking at the traffic to retails and recreation alone. NZ is about 5.5 times more effective at reducing unnecessary contact in this category alone. (55% remaining traffic vs 10%).

Social Distancing ONLY works when it’s effectively implemented. If a community has a significant population that isn’t committed to practice effective social distancing, the spread of the virus may be slowed down, but can not be easily eradicated without a great toll on lives and the local economy. Exponential viral spread needs an exponential response.

The Freedom Problem

An unfortunate reality in the US is that many local leaders in the US are facing great political pressure to keep their constituencies in lockdown, which is NOT a political issue to begin with. It’s America after all, and people love their freedom to death. But caving into the political pressure under the current circumstance is a bad idea, here’s why.

Let’s do a simple mental exercise. An official essentially has three options when it comes to dealing with this pandemic:

Shutting down the economy and enact quarantine is effective at containing the virus, as proved by New Zealand’s case. But the community will incur the loss of productivity for the duration of the shutdown. In most places though, the stockpile of strategic supplies should keep up with the demand of essentials for the duration of the shutdown.

Not shutting down at all will kill tons of people. More specifically, 0.5-5% of the community will be eradicated, since everyone is suspectable to infection. Willing letting people die is unacceptable, that’s manslaughter. But just for the sake of argument, the economic toll of losing such a significant portion of the population is going to likely cost way more than the loss of productivity for a month.

It may be politically favorable to choose the rather moderate option of a partial shutdown. In the politically polarized US, this move may just keep you in the office for a little longer. Well, Mr. Mayor/Governer, the bad news is, a partial shutdown may do as little good as no shutdown at all. The spread of the virus can’t be slowed to eradication, meanwhile, the economy is running at low productivity. Worst of all, this is going to cost the community way more time than the complete shutdown scenario. Lower productivity will cause a shortage of essentials and food, which could cost even more lives.

The Take-Away

Officials in the US who don’t want to manslaughter need to start acting with more backbone to commit to a comprehensive, enforced, and data-driven shutdown focused on reducing human mobility. In today’s world, freedom for humans also means freedom for the virus, freedom for our enemy. However, if we can all agree to limit our freedom for as short a 1 month, we can eradicate our enemy from our communities. No more politically moderate partial shutdowns! Because a partial shutdown or no shutdown is way less optimal, we need to either commit completely to an effective shutdown or pay the price with human life.

Hope everyone stays safe and healthy out there!

The post Social Distancing Works – New Zealand is a Living Example appeared first on Dennis's Random Blab.

I built this tool to better visualize COVID-19 data through the lens of simple mathematics. I hope you find the graphics helpful when trying to get a grasp on this complex situation. This is a good faith project, please use with discretion

I first built the UI on some existing data APIs, but later I found none is consistent enough for from day to day. No one is to blame, it is a rapidly evolving situation. So I decided to build my own data engine based on raw datasets from Johns Hopkins University

What it does

The front end provides a user-friendly interface to browse and explore all known locations that have been affected by the virus. The dropdown menu allows you to browse through the various regions in the world. A logistic curve is fitted onto the actual data with a least-square optimizer.

The Math

Fitted Logistic Curves

*For beginners check out this Video by 3Blue1Brown on the math behind pandemic growth

The total confirmed, deaths, and recovery curves of a pandemic roughly follow a logistic curve over its course in a community. Of course, there are a lot more factors that come into play when modeling an pandemic. This study makes NO attempts to account for explicit factors.

Each curve in the dataset is fitted to the following ideal logistic model

In this model, A accounts for the amplitude of the curve, essentially predicting the ceiling of the pandemic

𝜇 represents the center of the logistic curve, it marks the estimated inflection point of the pandemic

𝜎 represents the growth factor of the curve, aka the “sharpness”

Each curve is fed through a least-square gradient descent optimizer against the ideal model to compute the parameters. Note that not all datasets can be successfully fitted, the optimizer can’t converge on those datasets with too little data points or non-ideal shape.

I decided to plot ahead of the fitted curve 10 days ahead of now so you could visualize the current trend. Please also note that this is NOT a prediction of the course of the pandemic, it’s merely a rough forecast from the currently known data points. No one can predict the future.

Derivatives of Logarithmic Data

During exponential growth, the log plot shows a linear growth. The slope of the log chart, therefore, informs the speed of the growth. The slope chart s(t) is defined as

Similar logic follows. In a polynomial function, the second derivative indicates concavity. The second derivative of the linearized data gives us the concavity of the growth curve. A positive value on this curve means accelerating spread, while negative value points to the decelerating spread. The concavity chart is defined as

How I built it

The server side sits on a Django MVC backend. I’ve created a data processor to aggregate JHU’s raw daily reports into time series correlated with locations. All data is saved and served from a mysql database with schemas defined in the Django model. The backend also has a curve fitting engine which computes logistic curve parameters give a set of input data points.

The front end leverages Materialize CSS as the main UI framework. Of course, all the heavy lifting in logic is done ins JS with the help of JQuery. The charts are plotted in chart.js.

Challenges I ran into

The biggest challenge of this project was to find a clean data source that would display the time series accurately and consistently. Initially, I leveraged my frontend off of existing open source APIs. However, due to the rapidly changing nature of the situation, the existing data APIs can not provide a consistent data set over time. So I decided to build my own from JHU’s raw data sets. My data processor is very robust and resilient against data format changes, key changes, etc.

What I learned

Stay away from unreliable Data APIs. If you do end up building one, make sure your API is smart enough to resist some degree of inconsistency from the raw data source. Use a database to properly manage your data, use tricks like avoiding duplicate entries, using unique ID to identify your entry, etc…

Closing Remarks

This app was also submitted to the COVID-19 Global Hackathon, please give me a heart if you found this tool helpful! https://devpost.com/software/covid-19-timeline-with-logistic-curve#updates

I plan to run this app off of my website indefinitely. Data will be updated on a daily basis. Hope you all stay happy and healthy!

Happy hacking!

The post See Ahead of the Curve, a COVID-19 Visualization Tool appeared first on Dennis's Random Blab.

Work

“Work” got quite serious this year! I committed to taking my first full-time job ever. The 3-month process of job searching was proven fruitful. I was fortunate and am grateful to have had the opportunity to consider Amazon, Qualcomm, Zoox, and Cubert as potential employers.

View this post on Instagram

Life Update! After 3 months of adventurous funemployment, it’s finally time for me to be a productive member of society again. I’m happy to share with you that I have just joined Apple full-time as a Hardware Design Engineer(aka HW System Integrator) working on cool futuristic stuff! Just send it, and dreams will come true! Also thanks @deenahsaurus the queen for helping me with the move! I’m officially a nerd who lives in the Silicon Valley now! #fullsend #sendit #apple

A post shared by Dennis Ren (@dennisren1012) on Mar 3, 2019 at 11:17pm PST

Why did I choose Apple?

Weighing all aspects, I realized that the one single most important thing that I want in a job right now is the opportunity to learn over salary. In some ways knowledge and experience are not like money, once you have earned it, it’s not going away. At the same time knowledge and experience are also like Money, the sooner you acquire them, the more they will appreciate. Apple was not the highest paying offer, but throughout the interview process, Apple was the only place where I feel genuinely challenged, and the only place where I find the interviewers extremely competent. I knew then that I wanted to surround myself with these folks to start off my career.

I know that I want to eventually build my own company. I’ve tried numerous times and failed 100% of the time in the past. But that is okay because I learned some very valuable lessons from those experiences. One philosophy I picked up presents the following argument. Startups are born in chaos, but they all need to mature into more structured institutions as they scale. If you have only ever done a startup, you will only know how to work in chaos and scramble to meet your goals. On the other hand, if you have a background at a large, established company doing critical work, you will know exactly how to find order in chaos and bring growth. You will have a much clearer mental picture of how to build workflows, assign tasks and roles, manage time and resources. I consider myself a person who thrives in chaos, as demonstrated in my past experience starting clubs and leading student teams, I have the startup gene in my blood. Picking up work experience at a large company’s product system integration team is exactly the compliment I was looking for.

What I like about working

Well first and foremost is gaining financial independence. I no longer have to rely on parent’s support or loans to get by. Having a steady income is fantastic because it not only fulfills most of your spending needs, it also eliminates the anxiety of always getting so close to being broke. With a steady income, I’m now able to make plans towards significant financial goals. 

Another thing I love about being a working person is the fact that weekends are sacredly untouched. No more cramming for exams over the weekends. Saturdays and Sundays belong to you and you only and nobody can take that away from you. You can now start to make weekend plans way ahead of time. What having a midterm during Coachella?!

And an obvious awesome reason is that my role at Apple grants me access to the inner working of some of the most successful products in the world. That’s just straight-up wicked cool!

What I miss about being a student

The transition from being a student to a full time working professional provided interesting contrasts for reflection. Having a job forced to adopt routine in a day so that there is enough time left to do all the things I want to do in a day. Work is fast-paced and packed with fun, but can be demanding and stressful at times. I really had to learn how to effectively manage my time from day to day, more than ever before. I also had to learn how to say no to requests. (I have a tendency to sign up more work because they sound cool to work on).

Another thing I do miss about being a student is the ability to skip classes and take days whenever I needed it. I’ve heard people say that flexibility with work is a blessing. I didn’t realize how precious flexibility is until I’ve entered the workforce. Due to the nature of my work, both being a Hardware engineer and being on the system team, working from home or remotely isn’t an option. Though leaves can be granted for appointments and running errands, it simply doesn’t feel like freedom when you have to ask for permission. 

Make no mistake, I am very happy that I have moved on from my student life even though I miss certain aspects of it. Life moves forward and this next chapter is looking more and more exciting as I live through it. 

Fun

Sky diving

I picked up skydiving this year!! It’s the one thing that’s been on my goals list ever since I did my first dive after highschool. In May this year, I started my journey to become a certified skydiver. I opted in for the A-license program, which allows you to jump solo anywhere in the world after completion. I have finished all of my 25 required skydives and just waiting to finish my parachute packing certification now.

View this post on Instagram

Jumping out of an airplane was pretty fun! On to AFF Cat E! #AFF #skydiving

A post shared by Dennis Ren (@dennisren1012) on Apr 30, 2019 at 12:58am PDT

Skydiving is such a unique sport, it’s hard to describe the addictive thrill of being able to fly in thin air and maneuver around with ease, it’s the closest thing to actually being a bird. Once the dive is over, you also get to enjoy up to 5 minutes of pure bliss flying a canopy 3000ft above the ground. Being able to hang out high up in the sky really put me in perspective to the massive world around us. Can’t wait to explore more of this planet while falling through the sky 13000ft above ground!

Skiing

Skiing has been and always will be my main sport! The 2019 season was amazing! I bought a pair of Black Crows Camox as my new kicks and got to ride in fresh powder with them right away. I’m pretty proud of my progress overcoming the fear of big air this year. I spent a bunch of time practicing off of jumps, all worked up to a gnarly cornice drop at the top of Squaw Valley. This season, I wish to get involved with downhill racing and going heli-skiing!

View this post on Instagram

Another trip another send Jumping off of the cornice at Mainline Pocket at Squaw Thanks @quianastodder for taking the video and @downtown___brown for the co-send! #squaw #sendit #cornice

A post shared by Dennis Ren (@dennisren1012) on Mar 31, 2019 at 11:57pm PDT

Flying

Well, I think it’s pretty apparent now that I have a serious need for speed. I got to fly a plane for the first time this year. Initially, I wanted to scope out the process of getting a private pilot’s license, but after inquiring with my flying coach at the airport I decided it’s going to take too much time and I would pursue the license at another time. Nevertheless, I still got to take the aviation discovery class flying down the beautiful coast of San Diego.

View this post on Instagram

Check it out! Does your car also do this? First lesson and I’m official hooked #cessna172 #fly #pilot

A post shared by Dennis Ren (@dennisren1012) on Feb 27, 2019 at 2:20pm PST

I was quite surprised how much my instructor let me do give I’ve never been on a plane with less than 100 people before. With his supervision, I did a pretty much all the maneuvering including take-off (Of course he didn’t let me land the plane). Getting a pilots license has always been on my list, I wish sometime in the near future I will be able to find the time to actually get it!

Scuba Diving

Another super amazing and fun sport I picked up this year! I got my open water diver’s license in San Diego in the Spring, and my advanced open water license in Koh Tao, Thailand in November. 

Being able to hangout 100ft below the surface is wicked cool! The fish down there are so chill with you being there, it really makes you feel like you’re just hanging out with them. Tuning your buoyancy to match your weight underwater also creates a total weightless experience.

View this post on Instagram

Scuba diving in Koh Tao was definitely the most memorable part of our trip! Seeing and feeling the world at depth felt almost psychedelic. 20/10 would go back! Advanced Open Water License to 100ft! Meet awesome new friends! Chill by coral reef Get rekt at a ship rek Swim with fish from the cool school One post won’t nearly do it justice so I’ll have to share more later! #scuba #kohtao Nov 21-24,2019

A post shared by Dennis Ren (@dennisren1012) on Dec 21, 2019 at 5:04pm PST

I can only imagine that’s as close I can get to experience being in Space on earth without falling in a plane. NASA trains their astronauts in pools anyway!

Car

Tessy, my Tesla Model 3 Long Range, is Amazing! 

View this post on Instagram

Hello world, meet Tessy! Hey Tessy, meet world! Read more about how I got Tessy https://blog.dennisren.com/?p=116 Loving every second of owning this automobile, thanks Elon! #tesla #model3

A post shared by Dennis Ren (@dennisren1012) on Apr 27, 2019 at 8:24am PDT

She’s fast as hell and will accelerate your organs out of you! (quote Matt) After 9 months of ownership, I still think she is the most amazing car ever! The total cost of charging I’ve had to pay out of pocket is less than $200 for the 12000 miles I’ve driven in Tessy (thanks to free charging at work). Having an extensive supercharger network with my long-range battery gives me zero range anxiety. I’ve even taken her over the high sierras in snowy terrain a few times to go skiing at Mammoth, and she handles all terrains like a champ. I’m grateful and proud of what my ex-employer has created for the world!

Making

Back when I was in high school, I spent 90% of my free time making things and working on side projects. I was so constrained with the time between class and SEDS that I dropped the hobby for nearly 5 years during college. Well, that has changed. The regular working schedule gave me back guaranteed free time. I spend on average 20-30 hours a week working on my side projects. Probably went through 5kg of 3d printing filaments this year. I don’t want to go into too much detail on them before they are complete since they are still evolving. There definitely will be more detailed blogs about those projects once they are in good shape!

Health

Thanks to the health realization I had in 2019, 2019 was the healthiest year I lived since high school. You all know what the college lifestyle can do to your body. Not only you get fat, but your body also suffers from bad diets, bad sleeping schedules, constant stress, and emotional turmoil. The obligation of going to work each morning drives you towards establishing a routine. Although I’m far from being able to say I have a routine that I can be proud of, I do have one that works for me. And having this regularity has helped me with eating, sleeping, and exercising.

The working day makes eating regular meals on time much easier, whereas before I could go so long without eating a meal then all of a sudden I would get hungry and binge eat a large meal. In addition to being able to eat more predictably, I have also been doing the ketogenic diet on and off since October of 2018. Keto is the only diet I have been able to maintain for a significant amount of time. It really works its magic when the craving for carbs goes away a few days into the diet. Combined with moderate exercising this year, I have been able to maintain my weight at ~170-175 lbs throughout the year.

I must note that I have a lot of work to do on improving my actually-making-it-to-the-gym rate, as well as fixing my sleeping schedule so I don’t always stay up so late. Oh well, most days I still find myself having more stuff to do than the hours I have.

Books

Here are the cool books I got to read in 2019. I didn’t get to read as many as last year when I spent so much time driving around listening to audiobooks. Gotta pick up the slack in 2020!

Algorithms to Live By: The Computer Science of Human Decisions

I love the concept of the book! It resonated with me particularly well because I consider myself a methodical thinker, even when it comes to day to day life decisions. The book went over algorithmic concepts like sorting, searching, caching and applies them to daily lives. It provides both a very practical framework for you to systematically break down seemingly complex problems in life, as well as an applicable set of habits to adopt that optimizes different aspects of your life.

Bad Blood: Secrets and Lies in a Silicon Valley Startup

Oh man, this was one hell of a story. The writer went into such amazing details to cover the entire story of Therano’s rise and fall. If the book’s goal was to paint Elizabeth Holmes as the biggest lying piece of work on the face of the planet, well, it did the trick on me. The story also served as a striking wakeup call of how far fake hype can get before reality catches on. A relevant irony for the silicon valley today. Amazing story, highly recommended

The Hitchhiker’s Guide to the Galaxy

An all-time classic, now I know why I must carry a towel with me at all times!

Sapiens: A Brief History of Humankind

If you want a crash course on Anthropology, this would be the book. Don’t be fooled by its title, it’s NOT a history book. Rather it examines the development of the human race as well as the society we live in at a very fundamental level. I really liked how the breadth of subjects this book covered and how it strung an array of different subjects into one continuous timeline of human development.

I’m still working on The Signal and the Noise, I’ll write a few comments on it once I’m finished.

Investment 

2019 is my most active year in the market to-date. After all, I guess it was not a bad time to be in the market when S&P500 itself rallied 25%.

My retail portfolio only slightly outperformed S&P500, by a slight 2.15%. This comes to show how true Warren Buffet’s advice is. Investing in the S&P500 index is investing in the fundamental strength of the American economy. I actually spent a decent amount of time watching the market, picking stocks, and attempted to trade options. None of these activities seemed to pay off as consistently nor as generously at the S&P index. The mediocre performance of my portfolio won’t discourage my learning more and more about the market and the economic forces that power it. From this year’s experience, I think I will be keeping a good percentage of my stocks in the index fund in the upcoming years of investing.

Another field of investing I plan to dip my toe in is the world of quant trading (aka algo trading). I’m a firm believer that machines can be much more effective at analyzing the financial performance of companies and judge their value if it is fed with the right data.

Travel

Besides the countless short weekend trips to LA, SD, Seattle, and Vancouver, I got to spend a month overseas this year! 2 weeks in Shanghai, and 2 weeks in Thailand, and a day in Singapore. Since I grew up in China and have been to Thailand before, Singapore was the only new country off my scratch map. Gotta say, Singapore gave off straight up utopian vibes.

Goals

Oh my, time really flies once you’re past 21. It’s amazing how the lack of a developmental milestone can change your perception of time so much. This shows how important it is to set “milestones” for yourself. Here are the goals I set for myself for this past year.

Work

• Work a fulfilling job, keep up the entrepreneurial aspirations
  • Check. I’m happy with my job, but still are spending time outside of work exploring side projects and potential startup ideas
• Grow my network in the startup world
  • Half, I only went to a handful of events but didn’t really make any new meaningful connections. I can’t let myself get contempt in a big company and lose touch with the real world out there
• Attend at least 2 tech conferences, no much how expensive
  • Nope, I completely failed at this one. I must defer it as a goal for 2020.  

Fun

• Ski Hangman’s without hesitation
  • Check, went shredding hard for the season. Not only I skied hangman with style, but I also managed to huck off a huge cornice
• Learn backflip on a tramp, get over the fear
  • Nope, gotta do it this year!
• Resume my hobby, build more hardware!
  • Check, hell yeah! My maker hobby made a full comeback this year, I spend up to 20 hours a week working on side projects and making stuff.
• Pick up a new outdoorsy hobby
  • Check, Scuba diving, sky diving. I feel closer to mother nature than ever

Health

• Maintain 15% body fat
  • Half, I managed to drop my BF% from 26% to 17%  this year, but not quite at 15% yet. Still more work to do!
• Run a 7-minute mile
  • Nope, well, I guess I didn’t really run outdoors at all this year. That will change!
    • But, I managed to top Yosemite’s 4-mile trail under 2 hours, pretty darn proud of myself for that! (4.7 miles, 3200ft, sustained ~500W output over 2 hrs)

Family

• Go on a trip with mom and pop
  • Nope, It’s a shame that I don’t live in the same country as my family. This is a reminder for me to set aside time to spend the the fam.

And here’s a cliche ending, but I gotta say it. I can’t wait what 2020 has in store for the world, the people I care about, and my mind, body, and soul!

The post 2019, a Year to Remember appeared first on Dennis's Random Blab.

So here it is, I will try my best to recapture every step that I went through to become take Tessy home. If you’re thinking about getting a Model 3, I hope this could help you alleviate some anxiety.

Step 1: Figure Out What Config is Right for You

My Tessy is a Long Range RWD Model 3 with Premium Interior, black exterior and interior, and AutoPilot.

Tesla’s configuration offerings are always changing. Since I can’t predict what will be available in the future, I will just briefly touch on how you may want to go about making this decision and why I choose my configuration.

Drive Train:

This boils down to two key metrics, range and acceleration. Ask yourself, Do you often take long roadtrips? Do you wish to accelerate absurdly fast for? My answer to those questions was yes and no. I’m a big skier, so being able make ski trips is a big factor for me. On the question of acceleration though, that sounded just like some evil pleasure that I shouldn’t let myself waste money on. To be totally frank, my non-performance Model 3 is already by far the fastest car I’ve ever owned, it already beats out 99% of cars on the road today, I didn’t feel like I needed to get to the 99.9%.

Trim:

What trim you want is purely personal. Just know that any color besides black is going to run to a few thousands more. I didn’t care enough about my car’s color to go and spend that extra money.

Autopilot:

Why even buy a Tesla and not get Autopilot?! Autopilot is seriously a game changer. My driving model has become “oh, I’m tired of driving now, I’ll just let Tessy take over”.

However, I do not recommend getting the FSD package as of today. Tesla’s Full Self Driving technology won’t become available for another year or two, the maturity date is going to be even longer out(you don’t wanna be the guinea pig and put your safety on the line). In my opinion, the FSD package won’t be worth it until a time when FSD is not only feature-complete but also well proven after a period of user trails. What the FSD package offers today is more of a novelty(lane changing, on/off ramp) that adds another 10% autonomy to your driving.

Step 2: Order Your Car

Once you are happy with your configuration, go ahead and place and order. You need to pay $2500 to place the order, this CAN be paid by a credit card.(get those points!)

Once you pay your deposit, you will receive instructions to register for a Tesla Account. Your Teala Account will be the portal to everything you need to do with your car.

Next, you will need to provide some house-keeping information such as your address, SSN, income, etc. You will also be asked to upload a copy of your current insurance. You don’t need to change your insurance or anything, just upload it.

You now have to choose a method of payment.

Assuming that most of you won’t be paying with cash, that leaves you with either Tesla loan or your own financing. I highly recommend Tesla’s loan program. The way it works puts you at no risk. If you go with Tesla’s loan, you are still welcome to go find better rates with other credit unions. If you are able to provide proof of approved loan at a lower rate that Tesla offers within 7 days after delivery, you will get a check to compensate for the potential savings you would get if you go with the CU. TLDR, you can’t lose. At this step, you will also be asked to input a loan term.

Note: you should start looking for Credit Unions ASAP at this point if you think you can beat Tesla’s 3.75%(As of March 2019)

Tesla now has enough information to run your credit. The next business day, Tesla will come back to you with a Conditional Approval for Financing. You will have to upload some additional documents to lock down the loan. You will need:

• 2 forms for Proof of Income, below are acceptable documents
  • Last 2 pay stubs
  • Employment Verification
  • Offer Letter
  • Previous year’s W2
• 1 Proof of Residence, you can use:
  • Utility bill
  • Lease agreement
  • DMV Documents

You should be getting a good final number for your down payment at this step. Note that this amount is paid in addition to your $2500 deposit. This payment MUST be cash (aval in your checking account). Mine boiled down to this. Yes, this is a lot of taxes and fees, bummer, but this is California…

Step 3: Prepare for Delivery

Model 3s nowadays are getting produced lightning fast. I ordered my car on a Sunday, I saw my car’s VIN appear on Tuesday, and got my car on Thursday. You will pretty much need to have all the cash ready to do this once you order. There isn’t really any time to buffer.

Anyways, once you get your loan stuff sorted out, someone from Tesla will contact you to arrange delivery. They’re very flexible with delivery since I was in the bay area where the factory is at. I even had my delivery address changed super last minute and that was no problem. I can imagine that it probably won’t be so flexible if your car needs to come off a truck and get dropped off in front of your house. One action item on the buyer side is that you need to make sure you have the car insured the day of delivery, meaning that you need to change your policy the day before.

Step 4: Take Delivery

I recorded the entire delivery process, as you can see, I was pretty friggin stoked

Paperwork was very straightforward. You sign a bunch of DMV stuff, and a Tesla document acknowledging that you accept the car. You should give the car a thorough inspection before signing. If you do find any cosmetic/functional issues with the car, you have 3 days to complain about it to Tesla and they will fix for free. If you applied for a new license plate, expect to see that in your mail in around 3-5 weeks.

Step 5: Care and Feeding

You would definitely want to take care of your new baby car. Here are a few aspects I can shed some lights on.

Protection:

You should definitely get a screen protector for your display right the way. Amazon has a bunch of good options.

You will also want to protect the shiny finish of the center console, door handle, and other trims with some vinyl. If you have access to a laser cutter, I recommend this repo (https://github.com/Kenrik/Model-3-Vinyl-Wrap-Template) where you can get vector graphics files to cut any vinyl wrap. Otherwise, you can find some wrap already cut to size on Amazon. Use some soapy water when applying, it does wonder!

Charging:

Your Model 3 comes with a basic super slow 120V/240V charger. I forgot the exact wattage, but it would take around 24 hr to go from 0-100%. I recommend getting setup the some the following charger networks. They are all free to register. They usually offer lvl2 charging up to around 6kw. That’s about 10hr from 0-100%

• ChargePoint
• EVGo
• Blink

Supercharging is another options for you, but I don’t recommend using supercharging as a regular mean of getting charge. Charging at such a high rate all the time can degrade your battery pack faster. I reserve supercharging to only road trip needs/ emergency situations. Economically speaking though, supercharging is actually on par or even cheaper per kWh compared to the network of chargers listed above.

Carpool Sticker:

All CA owners are eligible for the sticker, period. The current purple sticker program is valid until 1/1/2023

If you make over $150k gross during the year of purchase though, you are ineligible for the $2500 state rebate.

Flooring it:

Full send all the time, oh man flooring this car is way too much fun. Caution yourself because you are going to get addicted.

Roadtrips:

With the supercharger network, I feel zero range anxiety associated with owning an EV. I’ve already done two major trips, from Bay<->Tahoe, and Bay<->LA. Both trips included brief charging stops where I was able to use the bathroom, stretch and get some food. Most superchargers can dump up to 120kW into your car, that’s an absurd amount of power really. You will be getting about 500mile/hr of charging from 0-60%, about 250mile/hr of charging from 60%-80%, and about 150mile/hr to go to 100%. I suggest you keep your battery below 80% and make more stops, it actually shortens the total trip time.

Loving your Car:

Your new ride deserves some serious love. Take her out to scenic spots and take pictures! Or just sit and enjoy her company in romance mode. Can’t to create more memorable moments with Tessy along the side. <3

Wrapping up

Hope what I was able to document and share if helpful to you in one way or another. Getting Tessy into my life has truly changed my life. Thanks Elon for making Amazing cars, and I hope more and more people will get to experience the magic of owning an EV!

I you ever want to buy one yourself, feel free to use my referral code, you’ll get some free supercharging! https://www.tesla.com/referral/junhan78195

The post Quick Guide to Buying a Tesla Model 3 – April 2019 appeared first on Dennis's Random Blab.

Shooting plane taking off turned out to be a lot tougher than I imaged, even during the day. The planes move fast, they are far from you so you have to zoom. That makes making a steady exposure a huge challenge, given I didn’t want to crank the ISO way too high. Out of 50 pics I took, only a few turned out decently clear. The airport itself turned out to be a beautiful sight at night time though. So many different colors used on the runways.

The post LAX Plane Spotting appeared first on Dennis's Random Blab.

https://pypi.org/project/scrapeswa/

If you fly southwest, you probably know that you can only book their official website, not through a third party. This makes the booking kinda painful. When I fly, I usually use Google Flight’s powerful filters and gadgets to help me narrow down to the most desirable flights. On southwest, it’s kind of a brute force effort.

Worry no more! My python package called scrapeswa can help you get all the useful information about your next trip in one command.

I realized that Southwest’s website is actually very scrapable. The site doesn’t contain CAPTCHA challenges nor anti-scraping features. The caveat is that it’s built on react.js, so it requires more than a simple HTTP request to get the info you need. To solve that, I made use of the handy Selenium automation framework +  headless Chrome Web Driver, essentially mocking a real chrome window to render the page with JS except not actually using chrome. The scraping effort is rather slow, unfortunately, because your machine literally has to render the entire application from scrach. If you are using a decent rig with good internet, you should be able to scrap one roundtrip query within 3 seconds.

Details on the usage of this library are available on my GitHub repo. This tool is simply a mock “API”. I will write about my motivation behind building this tool after I finish my intended application based on this tool.

Happy hacking!

-dr

The post How about an “API” for Southwest Airlines appeared first on Dennis's Random Blab.

I’ve been interviewing around these days, believe it or not, sites on the StackExchange network actually have great sets of practical problems that are likely to be asked during an interview. For the interviews I’ve had, they’re all geared towards solving real applicational problems. Practicing solving problems people ask online can be a great way to get yourself up to speed, it’s even better when you can cross check with the most upvoted answers right the way.

So I spent a few hours this week building this handy little tool.

Start by selecting a StackExchange site. Eg. Electrical Engineering or Stack Overflow

Then type in a topic of interest, hit enter.

My backend now will query the StackExchange API and grab the top results. This might take a few seconds.

Once all the cards are up, read the questions, try to solve them yourself, then click “Toggle Answers” to see the answers. The answers cards will be tabbed by the number of upvotes.

To-do list:

Add MathJax interpreter

Allow lazy loading

Cache popular queries to reduce API calls

Contributing:

https://github.com/rmr1012/stackQuiz

This tool is built as a Django App. If you would like to contribute, clone the repo and place it in a Django boilerplate server. Then add “stackQuiz” to “INSTALLED_APPS” list in settings.py, also don’t forget to route the endpoint to the app via urls.py

StackExchange gives any user up to 300 free queries a day. If you would like to get more while developing, you can sign up for a free API key.

Happy hacking!

The post Interview Prepration Tool – Stack Quiz appeared first on Dennis's Random Blab.

I haven’t always been a person who is good at reflecting, but as I get older and experience more and more, I can’t help to think that maybe it’s time for me to start systematically organize my progress, accomplishments, and learning in an apparent matter. This blog is my attempt to do exactly that, to capture my 2018, to remind myself of the lessons learned, and to create a benchmark for the years to come.

Work

2018 was a great year for my work. I use “work” as a generalized term for things I do that impacts the communities around me, either with or without commercial/employment connotations.

Colossus

2018 is a COLOSSAL year for Colossus. Started way back in 2016, after two years of non-stop work on this grand piece of hardware, Colossus finally saw it’s launch in February 2018. Our team pulled together an awesome launch party, inviting sponsors and advisors from all over the country to witness the ribbon cutting of Colossus.

Here’s some cool videos and pics from the Colossus Launch Party

I remained to lead the team until the end of Winter Quarter. Since I was graduating, I wanted to make sure that there’s enough time for me to transition the leadership of the project to the next lead and also giving myself some spare time to focus on errands with graduation.

Colossus further matured under the leadership of Jon Kavner. We conducted a series of tests throughout the spring to make sure that we are all set to perform the virgin hot fire of Colossus, the first big technical milestone in the operation phase of the project.

During this time, we had the fortune to bring Colossus up to exhibit at the center of the International Space Development Conference in Los Angeles. Getting Colossus inside of the venue took us 10 hours of non-stop work overnight. We actually had to disassemble part of the system, take the wheels off in order to fit it through the hotel door. Many exhibitors came to us the next day wondering how the heck we got it in there, I’m still impressed today that we pulled that off!

What’s even cooler, Jeff Bezos, yes JEFF BEZOS the RICHEST MAN IN THE WORLD stopped by Colossus to check it out. I had the fortune to hang out and chat with him!

On the last day, I spoke in front of the conference on behalf of my student organization, SEDS UCSD. 

Overall, that was the most magical conference I’ve ever been to. What made it so special was largely from my pride in the success of Colossus, my brainchild for the past 3 years.

In June, Colossus finally ready to rumble. After a quarter of intense validation and verification, all systems is a GO. We headed to the Mojave desert for this memorable day.

http://jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=2569&fbclid=IwAR3QvtyY4n0Cdc0tNkZ-glLPtrwnGYHkd9C777tuKcMFXM3_E1QrcoP47jY

Fun fact, I actually skipped my commencement to be there for this event. That’s how important this project is to me.

That day marked a period to my contribution to Colossus as the Project Manager and Chief Engineer. Sad to leave, but happy to see Colossus all grown up and ready to take on the world!

Galactic Unite Gavin Jones Prize

guscholars.ucsd.edu

I got a taste of non-profit work this year. I plan to write about the story behind this effort in length in another blog. To keep it short, I came up with the idea of starting a mentorship-scholarship program at UCSD for future space leaders after I saw a similar program took off at SDSU. Early conversations were exchanged between myself, Scott Borden, donor of the SDSU program and Maja Muric from Virgin Galactic. After months of pitching, revising of plans, I finally secured support from UCSD, funding from Mr. Gavin Jones, and mentorship commitment from the Virgin space companies. The program became administratively nested under the Gorgon Center at UCSD, thanks Shane, Ebonee, and Amanda for all your support!

In July, the application process of the program launched into a success. The pool of applicants was carefully vested by the selection committee. Without the help of the following reviewers, the program wouldn’t have happened, thank you!!

• Deenah Sanchez, Virgin Orbit
• Ebonee Williams, Gordon Center
• Shane Moise, Gordon Center
• Justin Herrera, Virgin Orbit
• Edmond Ngo, The Spaceship Company
• Deepak Atyam, Tri-D Dynamics
• Alex Finch, Tri-D Dynamics
• Jesse Lang, Tri-D Dynamics
• Kim Weed, Virgin Orbit
• Cameron Flannery, UCSD RPL

After half a year of planning, the cohort was finally selected. (http://jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=2663) Congrats to the following scholars, wish you all a great year with your mentors, and a successful launch of your career that will impact the space industry in your own unique and meaningful ways.

• Evan Kay, RPL UCSD
• Ross Libman, RPL UCSD
• Philby Wang, SEDS UCSD
• Jack Najarian, SEDS UCSD
• Surya Vohra, SEDS UCSD
• Riana Menezes, Cubesat UCSD
• Tiana Menezes, Cubesat UCSD

My two brain children of the year both made it to the Jacobs School of Engineering Annual Student Highlights!

http://jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=2691

Amazon Internship

I had a summer full of nerdy fun at Amazon’s Amazon Go cashiers store! For those who are not super familiar with Amazon Go check out this official video:

Although I can’t say much about my work there, I can surely tell you that I had a great time working there this summer. Seattle is a fantastic city to live in (at least during summer)! It is super walkable, great public transport, and full of millennialish good vibes. People say Seattle is San Francisco with a soul, I can totally agree to that!

I’m so happy that I got to work with so many amazing coworkers there. My team was young and dynamic, we frequented pretty much all the near by restaurants and pubs as a team, Teku Tavern in particular. Gotta love those moments when one person starts asking around the office “beer? beer?”. And you guessed it, my response was always “I’m down!” I worked a ton this summer, perhaps a little too much, but I couldn’t help it because I get so sucked into a problem that I literally can’t do anything else unless it’s at a savepoint. Yes literally like a savepoint in a video game. There are a few fun twist to my internships.

Twist 1: Operation Foam

So my buddy Kenneth threw a massive intern rager during summer. Unfortunately I wasn’t able to attend, but being the only person with a car in the group of friends who planned that party, I volunteered by car to shuttle beer kegs. Well, Kenneth overestimated the amount of beer people were going to drink, so I ended up with 3 full kegs in my car. I show up to work on a Monday and boldly brought the keg to my desk, everyone was LOLing at it. Later I actually convinced my manager to throw an office party because there’s a team member leaving just that week as well. We had one problem, though. The keg needed to be chilled and we didn’t have a kegerator. The crisis was resolved when one of my friend came and told me “hey there’s a thermal chamber in the reliability lab”. Without disclosing further self-incriminating details, here’s a picture for your imagination…

Twist 2: Camp 201

I actually ended up homeless for the final two weeks, so I camped up in the storage room at work with my sleeping gear. Amazingly, no one was aware of it until I told some of my close friends. I would use the shower in the building each day, work until midnight, get up at 8am, repeat 10 times.

It was tough to leave Go, not only because I miss my brain children, but also my coworkers. Great times indeed!

Fun

“If it ain’t fun, don’t do it” — Richard Branson

Skiing

The 2018 season was one of the best to date. First year to ski on a pass, probably spent over 15 days on the slope. I feel compelled to share some of the footage of me eating shit.

note: we went down Hangman’s Hollow at Mammoth, the steepest run on the mountain no problem at all, but got destroyed by a hidden cat run that i couldn’t see, RIP

On the more positive note, here’s a great run I had down Dry Creek this fall. I have worked to improve my physique and endurance, otherwise there would be no way I could finish this following run in one go without taking a break.

Sking is my true love when it comes to sports. With the Ikon Pass this year, I plan to explore many other mountains, try new skis, hit bigger jumps, shread gnarlier runs!

Traveling

Although I stayed mostly in the US this year, I still got to see many new cool places. New states added to my scratch map:

• Oregon
• Texas
• New Mexico
• Arizona
• Colorado

Deenah and I took two vacations together, first one to Portland during spring break, another one to Austin Texas during Christmas.

In September, my college roommates and I took a mega road trip together. We spent 12 days driving through Arizona, New Mexico, Colorado, Utah, Nevada. This trip is worthy of a blog post on its own. I haven’t had time to organize that, but stay tuned, I’ll have more to share soon.

Health

2018 was a GRAND year for my health. I’ve always had that “I’m invincible” mindset from my teenage years. Taking care of my body and health was one of the last of my concerns. Marching into senior year, I could visibly feel that my health is going down hill. I used to pull quadruple all-nighters as a freshman, I can’t even imagine during one all-nighter now. I started to feel constant fatigue, I find myself over-eating constantly. I ate too much crap, didn’t drink enough water, the list goes on and on…

This fall, free from 30 hours a week of SEDS work, I shifted my focus to myself. Taking care of my health has been something I wanted to do for a long time, but kept putting it off by excuses like I’m too busy. But sometimes you just gotta send it, which I did.

The first attainable goal I wanted to tackle is my weight. Over the 4 years of college, I’ve gained 20 pounds of pure fat. BAD! Along with trimming my weight down, I also really wanted to become more fit and have better cardio for the ski season. Just so that Scott won’t have to wait for me everytime I had to take a break when I tap out.

I’m happy to anouce that I’ve lost 15 of those 20 pounds at the time of writing! And this whole process took me little over 2 months. Thanks to my girlfriend Deenah, we decided to both enter a ketogenic diet together. Trust me, it is sooooo much better when you do a diet together with a loved one, and sooo difficult when you aren’t. Deenah has lost about 18 pounds so far as well.

I followed a strict Ketogenic Diet while maintaining a 600 calorie deficit a day, in addition to working out 5 days a week. The math adds up quite well, Since one pound of fat equates to approximately 3000 calories, I was able to lose about 1.5 lbs a week. For those who have questions about keto, I can tell you that it is actually quite easy to follow and very fulfilling, given that you are a meat lover.

You can see a huge dip around December 20th, that’s my what 4 days of skiing does to you. Then you can see that I bounced back real high because of Christmas and eating non-stop for the holidays. I currently weight 181 lbs, 15 lbs less than my 196 start weight.

And is an obligatory before and after comparison

Now that I’ve reached my weight goal, I’m going to focus on my cardio health and my body fat percentage. I have gone from 22% fat to about 16.5% now, I wish to maintain a healthy physique around 12-13%.

Reading

I don’t claim to be a legitimate book reader. It’s almost that I have dyslexia, I just can’t digest information very well from a large volume of text. Rather I resort to audiobooks, which is a great way for me to fulfill my curiosity in various subjects. Here’s a quick list of books I “read” on Audible this year and some comments.

Principles

Awesome read on Ray’s success story and how he developed a detailed value system to guide his day-to-day life. The unique thing about this book is that Ray gives extensive insights into a type of organizational philosophy called “ideal meritocracy”, where decisions are made base on the best ideas, and people are awarded according to their merits.

Never Split the difference

Written by an ex-FBI negotiator, Chris gives a set of very easy to understand techniques that can be easily implemented by everyday people. Much of the book is stories of Chris’s personal accounts during his professional career which led him to come up with this system. He goes in length to explain the psychology behind these techniques and proven examples of success. I’ve personally put this book to work as I negotiated my car insurance, phone bill, personal training, and even a job offer. IT WORKS to say the least!

Outliers

Motivation book written by the legendary Malcolm Gladwell. In this book, Gladwell examines various successful people and investigated why they were successful. Throughout the book, Gladwell downplayed the factor of talent and luck but emphasized on the merit of sheer hours of hard work and the bonus of a privileged environment. His conclusion is along the line of you need over 10,000 hours to become a master (Robert Greene has a whole book on this), that we are all large products of our environment, and that only the most well prepared are ready for opportunities governed by luck.

The Google Resume

I read this book amidst my ongoing job search. Although mostly catered to Software jobs, this book still covers the non-job specific parts of job hunting. It gave pretty useful tips on a resume, cover letters, general guidelines on interacting with recruiters, etc… Could be pretty useful especially if you’re CS.

AI Superpowers: China, Silicon Valley, and the New World Order

Written by Kai-fu Lee, international tech exec. He gives a first-hand account of the current status quo of the tech industry in both China and US, the development and prospect of AI technologies and how they could impact our world. My key takeaway is that while the US is likely to stay on the edge of new AI technologies, China is going to dominate the implementation of AI into common day things. Great book overall!

World Order

Regardless of how people stand with Henry Kissinger politically, he is surely a master at international affairs and his insights are worth learning. Kissinger gave a comprehensive account of the way our world is structured, from the Treaty of Westfalia to today’s NATO. He comprehensively covers the principles of the Westfalian World Order, and the emerging powers such of China, India, and countries in the Middle East that seek to redefine this world order to incorporate to their heritage and values. The text is rather dense and academic, but it sure did lend me a new set of lens to inspect current day situations.

Checking in on My Goals

Here are my goals for 2018 I set forth during the last new year

• Get admitted to a top 20 Eng Grad School
  • Check, I got into the UCSD BS/MS program for EE, although plans have changed and I’m no longer going.
• Score a big 5 Internship
  • Check, I secured an internship at Amazon over summer
• Get weight to 175lbs
  • Almost, @180 now, almost there!
• Build a stunning personal website
  • Check, visit http://dennis.ren Although I’m still working on the “stunning” part
• Bring Resting Heart rate to avg <70
  • Check, according to my apple watch, my average RHR reduced from 72 to 68
• Figure out my 4 more year plan and commit
  • Nope, I’ve learned something important during this recent fall. That is, don’t over plan your future. Set a grand goal for your future, but don’t lay down each step of your implementation. Follow your heart, and you will get there. “You can never connect the dots forward” — Steve Jobs
• Have a published paper
  • Nope, although I had the chance to author a paper on Colossus, I didn’t end up pursuing it
• Get my 3.0 back
  • Nope, as I’ve figured out, I’m not really built for school

As 2019 unfolds, I wish that my new goals can be realized. I will share them at the end of the year this year.

Adios 2018, it’s been great! Here’s to more fun, more friends, more love, more progress, more adventures in 2019!

The post 2018, Year in Review appeared first on Dennis's Random Blab.

No, it’s not a click bait. With enough determination, you can make this happen for you too! But be warned, this hack is not for the faint hearted.

First off, let me share some of the performance specs of this hack.

• GeekBench SingleCore – 3798, Multicore – 7890
  • Note: Latest 2018 flagship Macbook Pro ($2500 + ) performs at 5678 Singlecore
  • Note: Beats MacBook Pro (15-inch Retina Mid 2015) Intel Core i7-4770HQ @ 2.2 GHz (4 cores) at single core
  • One more note, most daily trivial tasks weigh more on single core performance. Only stuff like rendering and training a neural net would require multi processor crunching power
• Battery Life: 6 hours
• Memory: 8GB
• Storage: 512GB SSD
• Weight 3.3 Lbs
• MacOS Sierra (installed last year, got lazy and never upgraded)
• Working Features
  • SD Card Slot
  • USB-C
  • HDMI Output
  • Webcam
  • Speakers
  • Apple Native Multi-touch
  • Backlit Keyboard
  • Sleep – Wake
  • Bluetooth features
  • WiFi Features
• iCloud
  • iMessage
  • Notes
  • Calendar
  • Mail
  • Facetime
  • Reminder
  • iCloud Drive
  • Basically everything you get with a Mac
• Untested Features
  • USB-C Charging
• Still having issues
  • Built-in microphone input

The cost breakdown of this hack consists of 

• $500 – Acer Swift3, refurbished  (ref new Amazon link )
• $35 – BCM94352G WiFi+BT Module (ebay search)
• $7 Audio Codec (link)
• $6 USB Hub (link)
• $2 SD Card Reader (link)
• $80 (Optional) 500GB SSD Upgrade  (link)
• $15 (Optional)Apple Stock Trackpad, Look for A1466 Model
  • 
  • Seasonal, check ebay for current price
• $10 (Optional) Vinyl Wrap for finish (link)
  • This is the best color match I could find, people actually can’t tell it’s not a Mac with the wrap lol
• Total : $655 

There are already plenty of Laptop MacOS Installation tutorials online. I’m going to just focus on the Hardware specific side of things here.

The Acer Swift 3 comes as a pretty solid budget mid-performance laptop. It’s one of the cheapest you can get with the performance metrics it offers, and conveniently, it looks almost just like a MacBook Air knock off.

Step0: Upgrade your SSD & WiFi

If you want to upgrade your SSD, do it now. It’s a simple swap as long as your have a M.2 SATA drive. Note: NVMe Drives are not supported on this computer according to my test

WiFi+BT

The OEM WiFi card is a intel card which MacOS has no support of, buy the card suggested above

Step 1: Install OSX

Without any hardware modification yet, install OSX so we can easily test each additional feature fix. After following the standard installation guide, you will need to face your first obstacle: Configuring your EFI correctly so that the OS/installation wizzard even boots. After you have your bootable USB ready, go ahead and use the EFI files provided here https://github.com/rmr1012/Acer-Swift3-EFI

Then babom! You should have a minimal working OSX installation. Besure that you have clover configurator handy on your newly installed Mac, other handy tools include

• MaciASL
• Geekbench4
• IORegistryExploere (From Apple Developer Downloads)
• Intel Power Widget
• Karabiner-Elements

Step 2: Test working features

At this point, there should be a bunch of stuff NOT working. Thanks to a good EFI you should at least have:

• Full-res graphics (thanks to IGPU drivers)
• Speaker Audio
• WebCam
• HDMI Output
• WiFi+BT

Features that require hardware hacks at this point include:

• Audio Jack I/O
  • The audio codec for managing the 3.5mm Jack is unsupported by OSX, buy the external USB audio card above and I’ll show to how to fix it
  • If you don’t use 3.5mm jacks, feel free to ignore this fix
• SD Card
  • ODM SD card interface is unsupported by OSX.
• Native Multitouch experience
  • The trackpad experience on non-Mac hardware is trash in my opinion. Most PCs use Elantec and Synaptics. Although there are some 3rd party Mac Drivers for both vendors (VoodooPS2, AppleSmartTrackpad), the experience is still heaven to hell compared to the true Mac experience. I can’t emphasis enough, without the smooth scrolling, rich gestures, and accurate tracking, you’re not really using a Mac.
  • But again, if you really don’t care about this experience, feel free to skip, your hackintosh would work just fine

Besides the WiFi requirement being super obvious, The other features are optional depends on how much work you want to do and how well you want your machine to run.

Aside: Mod Plans

The easiest most readily available interface in computers nowadays is USB. USB is awesome for us because it has a huge array of cheap products we can choose from, and very good support on the driver side. We usually use USB external to the computer connecting diffrent gagets, little did we know USB is also used heavily to connect the internal peripherals of a PC. For example, most of our built-in webcams actually sit on USB, so does a lot of Bluetooth interfaces.

We are going to focus on the expansion and use of the USB bus internal to the computer to fix and expand the features identified as not working above. We are going to hijack a existing USB port, inject a USB Hub in between, and add replacement peripherals on the new hub, then have the outputs connect to the mechanical connectors. All of this must be done within the tiny body of this PC

Step 3: Adding a USB Hub

Pry open the cheapo USB hub we just bought, a USB hub can be simplified down to a single chip. Yep, that’s all we need. We are going to strip everything away except for the very chip and some connection points. In my case, I identified the chip being this black gue-covered patch. I identified 4 out-going differential pairs and 1 in-coming diff pair. I traced the power buses using a DMM and identified the GND traces and the VCC traces (5V).

After stripping it down, promptly solder 30 Gauge hook-up wires to these pads. They’re delicate, be careful.

Now, let’s hijack a USB diff pair from the IO card. Cut the trace, connect the System-side of the trace to hub-usb-in, the connector side to one of the hub usb outputs

Step 4: Fixing the SD Card Reader

Unsolder/ cut traces to the 9 pins of the SD Card jack. attach hook-up wires on each of pin.

Prep the new reader, strip down to the bard PCB, identify the SDIO pins in order. It helps to hold a actual SD-micro in place to make sure your pin-mapping is correct

Now, connect the new reader to the SD card slot

Connect the USB reader to the USB hub, don’t forget the power wires, 5V and GND. Connect to your computer to test functionality

Step4: Fixing the Audio Jack

The onboard audio chip sits on SPI, which Mac doesn’t have support for sadly. Let’s fix that

Strip your soundcard to bare PCB

Connect the USB side to one of the hub outputs

This audio card in particular has two jacks, one 2-ch headphones, one 2-ch microphone. We really only need 1 microphone. The PC comes with a 4-conductor jack, two for L-R audio, on for Mic in, then of course ground. We are going to map the two audio outputs to the jack, and only choose one Mic input from the jack to feed to the chip

Cut traces on the IO card to disconnect the jack from the original codec

fly hook-up wires in, connect to new audio codec

Babam, you should now have a working audio card

Step 5: !!! The Native Touch Experience !!!

Here comes a touch of Steve. Man having a nice trackpad flow is almost erotic. Too good

Apple hasn’t not always used USB as the interface for their track pads. After some research I realized that only a short span from 2009-2013 is where you can find trackpads that has a USB interface. I choose the the 2013 Macbook Air trackpad because its newer, cheap, and fits perfectly size-wise.

By googling for about 30 seconds, you can find a schematic for the trackpad’s original mac

Try this

http://schemadata.blogspot.com/2013/03/apple-macbook-a1386-mbp-15mlb-macbook.html

Disclaimer: Found it on Google, I don’t endorse nor participating in data piracy

By looking up the schematic of the trackpad’s correcponding MLB, you can decipher the pin-mapping of the ribbin cable connector. Simple ctrl-F on trackpad keyword reveals this connector

Go ahead and find the D+, D-, 3.3V, 5V, and GND connections on the trackpad, these are all you need

I kinda did a bad job soldering this one, almost botched it completely lol

Put some epoxy over the connection to protect your delicate work, done!

Gently place the trackpad in place, the button lines up with the mechanical frame perfectly. Just need to cut a bit of plastic to make room for the wires

Voalaa!

Step 5: Body Works

Well, it ain’t not Mac if it doesn’t look nice. Let’s do a bit of fine body work to make it look like just that

Easy first-step, everything’s gotta fit inside. Not much I can show here, just gotta finesse your own way to make everything go in the shell. In my case …

Then, let’s work on the outside grind away the Acer logo with a dermal or sand paper

Don’t worry if it’s not super flat, we’ll fix that

Add some bondo to the surface, when dry, sand it flat

(Pic below it my botched attempt to spray painting the finish. It’s too delicate and hard to get even, wrap is better!)

Now, cut the wrap according to size

Stick a Apple sticker on there Done!

Step 6: Optimize Power and Performance

SSDT hugely affects the performance of your computer. I actually suffered from incorrect SSDT for almost a year until I decided to look into it. SSDT basically details the additional attributes about your computer and share that information with the OS. In our case, without proper SSDT, MacOS actually isn’t aware of the power states of the processor. Prior to optimization, I was getting 2 hours of battery life, and super slow computing speed. Geekbench around 1300 points…

And sadly, idling/working looks like this

This graph shows that the processor always chills around 900MHz, about 1/3 of its capacity, and 2W, about 1/7 of its capacity, for BOTH idle and working. This means that it doesn’t throttle down when chilling, and doesn’t throttle up when working.

Following Piker Alpha’s ssdtGen tool, you can generate the correct power definitions. Also, in Clover, play with the SSDT/PluginType, Kernel../AppleIntelCPUPM, Kernel../KernelPM, CPU/HWPEnable options. The EFI I shared should work out of box, but in case you want to furthur optimize, use these as a hint.

After: 

Look at that beautiful not-so-flat curve!

That’s it for now, happy hacking!

The post [Tutorial] How to Build Your Own MacBook Pro for $700 Dollars appeared first on Dennis's Random Blab.