I spent some time over the last few months continuing my electronics tinkering, and I’ve successfully completed two new gadgets along with a friend from school, Billy Keyes, as part of a week-long extravaganza at CMU called Build 18. It’s for ECE majors exclusively, and turned out to be a lot fun!

WARNING: Technical information follows. Skip down to the end for the pictures

Hard Drive Speed Game

When I got home from break, I was really anxious to try out a project that I ran across that made a “Spin The Hard Drive” game out of old 1-5 GB hard drives that weren’t being used anymore. So, getting the permission of my Dad, I ripped apart his old Western Digital and started playing with it. Since I didn’t have a scope back home, I had to guess a little bit on the values of the resistors for my voltage comparator. After a while, the green LED on my Arduino shield started blinking when I moved the hard drive, so I knew I hit the right spot. After adding a little hysteresis with a feedback resistor, it was working consistently enough to check it with an Arduino interrupt.

Switching over to the Arduino, it was pretty easy to set up an interrupt routine and convert over to RPM. See below for the code I used:

/*Hard Drive RPM Monitor*/
 
int interruptPin = 2;
long oldtime, difference = 0;
volatile int clicks = 0;
volatile long oldclick = 0;
int rps, rpm;
 
void setup() {
  Serial.begin(9600);
  Serial.println("Serial works...");
  pinMode(interruptPin, INPUT);
  attachInterrupt(0,click,RISING);
}
 
void loop() {
  if (clicks >= 4) { //Every 4 "clicks" is one rotation
    difference = micros() - oldtime;
    oldtime = micros();
    clicks = 0;
 
    //Rotations per minute
    Serial.println((int)(60000000.0/difference));
  }
}
 
void click() {
  //One "click" is 1/4 of a rotation
  //Delay should get rid of most false signals
  if (micros() - oldclick > 100) {
    clicks++;
    oldclick = micros();
  }
}

After making a little GUI in Processing to receive the Serial data from the Arduino and display it on the screen, I was ready to go! In the picture below, I show someone getting a high score, and the fastest I’ve seen people spin it is around 1350 RPM, which is pretty ridiculous! At Build_18, someone suggested using the hard drive as a DJ mixer, which sounded really cool and will probably be where I will go with this hard drive next!

Keepon Tracking

Our second project involved an old security camera with a built-in internet connection that I got for free last year. When I got around to buying the power cable for it, I plugged it in only to discover that the camera was broken (hence why I got it for free). So, Billy and I came up with the idea for using it as a dancing robot ala Keepon. After hooking up the camera, a USB webcam for facial recognition, and a microphone, we realized two things very quickly. First,the security camera only took commands every .6 seconds or else it would time out (bad for complex motion, but still ok). Second, sound data (particularly claps) are not very good for interrupts, as our interrupt would trigger multiple times during the sound wave and our various attempts to solve the problem weren’t working. To fix our sound problem, we ended up just checking thresholds on the analog values from the microphone and put in a small time delay to ignore the rest of the wave. Once we found the beats, we just moved the robot left and right in sync with the beat and in half- or quarter-time as necessary.

Overall, it was a great way to come back from break and hack around with some electronics. I’m looking forward to the next one!

After the summer, the whirlwind of school started again, and I’ve been non-stop busy with staying on top of my classes, Kiltie Band, Merritt visiting over Mid-Semester Break, and the college ministry that I’m attending (Agape). For anyone debating whether they will have time in college to attend a Christian student ministry, I would unabashedly say that the main reason that I get through weeks of studying and working is because of my relationship with my real Father, and his wondrous choice of me as someone to bless! Getting continually refreshed every few days in a solid ministry like Agape has helped tremendously, and I will cherish it long after I graduate from school. Anyways, as finals roll around and start next week I’ll keep trusting in Him for strength, as it’s worked pretty well so far. For everyone else wish me luck, and I look forward to meeting  you again!

//I had a little break over Thanksgiving, so I created a Lissajous Machine with some parts that I scrounged together. Enjoy!

I loved Reader’s Digest, don’t get me wrong. It’s one of those great bathroom reads, when you need some inspirational stories to get you through the day. However, once my parents’ membership ran out, they (Reader’s Digest) decided to take action to convince my parents that they need more money! I’m going to try a Better Business Bureau claim just for fun to see how far I can take this. Nowhere on the bill does it say that we don’t actually owe money, which makes this marketing scheme even weirder… I’ll keep you posted!

UPDATE: Well, it turns out that my parent’s didn’t check the box to decline RD’s opt-out service. Methinks they need to adjust their “billing” to at least remind someone that they’ve opted-in and can cancel at any time! Props to DayAnne at RD for the quick response and clarification.

EDIT: They mention this in a soft, soothing voice the video, but I want to point out that WES only runs during the morning and evening rush hours (5:20–10:00 and 3:30–8:00) on weekdays, which puts a kibosh in the plans of most evening and weekend shoppers. Hopefully they’ll expand this service in the future, but for now just leave an hour early from work and you’ll be fine.

CMU Carnival is about 3 things–No School, Booth, and Buggy–all 3 pretty equally important. We get Thursday and Friday off of school and the festivities don’t end until Sunday afternoon, which is awesome especially when the weather is really nice! Booth is a very eccentric CMU tradition where different student groups race to finish building a mini-house around the given theme for a year. Booths ranged from a giant “Wall-E-Pi” to a Giant Peach, a nuclear fall-out shelter, and even a giant Poke-Booth. The Kiltie Band also performed our Spring Concert to start off the festival.

Buggy is the other main event that occurs at Carnival. You might not know what it is at first glance, but it’s basically a hill race with customized racing buggies (over a few thousand a pop, if you want a good one) that often hit 40 mph at the bottom of Flagstaff Hill. 5′ tall women are aggressively pursued at the beginning of the school year to drive the buggies and ensure their team’s victory. Believe me–these teams are HARD CORE. The Student Development Council beat Pi-KA’s record this year, but I put a video from last year anyway to give you the excitement of what happens. 

Only 2 1/2 more weeks of school! 

The first is of “Tank”, the official Roboceptionist for Newell-Simon Hall on campus ( home of Carnegie Mellon’s Robotics Institute). He’s surprisingly really smart, as he’s does facial tracking, gives directions, says the weather, and I’m sure much more while keeping a slight grin on his robotic face. If you’re ever able to visit, be sure to talk to him at NSH north entrance.

The second video was from the Young Inventors International “Inventing the Future” Conference, held at Carnegie Mellon two weeks ago and organized by Anne Swift and Project Olympus, a startup incubator for students at Carnegie Mellon. Performing a market analysis of Marek Michalowski’s Keepon Robot was just one highlight of the event, as we were able to participate with roundtable discussions with numerous VC’s, marketers, inventors, and established CEO’s in an informal setting–all geared towards young, college-age inventors and entrepreneurs.

For a more detailed recap of the event with some more videos, please check out the YII blog at http://www.innovatorshub.com/

I was able to make a lot of connections and listen to some pretty inspiring stories, and I look forward to participating in it again next year!

Lastly, Carnegie Mellon and Astrobotic teamed up to show off their new challenge for Google’s Lunar X-Prize competition for $20 million. I was able to get the whole tour on video, but feel free to skip around as you want. My friend Abhinav and I were able to talk with Red Whitaker, the founder of Astrobotics, CMU’s DARPA challenge robots, and numerous other CMU robotics spinoffs,  which was pretty cool too!

Over the break, I mostly relaxed and visited family and high school friends, tried to play in the 16″ of snow we got (a 40-year-record for Portland), and did some website work. Before I knew it, January had rolled around and I was leaving to fly back to Pittsburgh. As most of you know, the Steelers won the Superbowl this year, but apparently the tradition is that all of the college students have a “party” in Oakland to celebrate afterwards. Their interpretation of party included burning garbage bins,  breaking a bus stop, trying to uproot trees, and generally showing their enthusiasm for Pittsburgh’s win. Once a few of my friends and I got there, most of the ruckus was calmed, and mounted patrol units started coming in to clear people out. I’m definitely looking forward to the next time Pittsburgh wins!

The week before last was “Engineers Week”, a nationwide celebration for engineers and by engineers. Carnegie Mellon demoed some cool student projects during the open house including the awesome Hexabot robot (made by a member of our Robotics Club) and a project called HandTalk that translates pseudo-sign-language into words on a cell phone.

Also, earlier this week I had a first experience with “snow showers” (not to be confused with the Northwest’s “<rain> showers”)…they were so weird! Lastly, we had a great Kiltie Band concert last night, especially because everyone played in their kilts!

I’m looking forward to a great 2009. So long!

Also, here’s a bonus panorama of the CMU “cut” and “mall” last Wednesday. After snowing last weekend, it has been 50° and beautiful in Pittsburgh these last few days, and I felt like taking a few pictures to prove it.

Later in the week I played in the Kiltie Band final concert, which was cool too. Skipping the ECE picture, the map of names is showing the hierarchy of a test that the “Science of the Web” professor Luis Von Ahn proposed to his students. Their task? See how many people could enroll in a facebook group. If they reached 3,000 people by the end of the week, they would get an extra 10 points on their final! The black circle in the top left corner is where me and a few of my friends are. Thankfully, they reached 3,000 people by Friday, and we got a really cool map to boot.

The last picture is of a new game that I discovered that is called Blokus. The game is basically like Tetris, except that you have to play the pieces at direct corners to each other, making the game a lot of fun for everyone, especially the engineering and computer science students at CMU. For those of you back home, I guarantee you, you will be hooked!

Can’t wait to come home for Christmas Break! Now…just to get through Finals