Arduino Your Environment

Mixing and Amplifiying Your Audio Sources

2012-01-28T09:09:00.000-05:00

As I build more complicated Arduino projects, I'm finding I have several audio outputs in one project. Instead of offering a amplifier and speaker for each source in the same project, I decided a needed a mixer, with one amplifier and speaker. The following talks about the various types of mixers (passive and active), the pro's and con's of each, and how to work through things like impedance matching, distortion and clipping.

http://www.all-electric.com/schematic/simp_mix.htm

For an amplifier, it's hard to beat a good set of amplified computer speakers for this application. The Logitech S120 2.0 Multimedia Speakers are very inexpensive (<$11), and give great quality sound.

BTW, today is my birthday, so please check out my Arduino Store, and you can celebrate with me!

The Most Important Arduino Book?

2012-01-05T06:03:00.000-05:00

There are a lot of good Arduino books out there. Most teach you how to install the editing environment, how to code, and neat projects like blinking a LED, reading a light sensor, or controlling a motor.

Only one teaches you about motion, the science behind it, and how to make your Arduino interact with the real world through electro-mechanical, pneumatic, and hydraulic ways. Learn how to size motors for a particular task, how to determine rpm and torque requirements, and much more.

I believe this is the most important Arduino book available, and it has a prized position at my work bench. I recommend it highly!

Making Things Move DIY Mechanisms for Inventors, Hobbyists, and Artists

Using Mosfets

2012-01-02T21:10:00.000-05:00

I'm working on a LED lighting project. The LED's consume more power than a Arduino can handle, so I'm using a IRL520 MOSFET to control the lights.

The first phase of the project is simple on and off, the second phase will PWM the MOSFET for brightness of the LED's. Third phase is 3 MOSFETS each controlling a different color bank of LED's for tonal control.

What we have working in phase 1:

+12vdc to 3 white LED's in series with a 120 ohm resistor

This configuration was determined using the LED Wizard at http://led.linear1.org/led.wiz

The next step was to insert a IRL520 MOSFET is series with the LED's, between the resistor and ground. The Drain (pin2) connects to the resistor, the Source (pin3) connects to Ground. The Gate (pin1) can be tested by connecting to +12v (momentarily, not good to exceed 10v) and Ground, alternately.

WAIT!

What have we discovered? The output (LED output) toggles with the gate connection. When we touch +12 momentarily, the LED's light up, and stay lit even after the Gate is no longer touching +12v. When the Gate is grounded, the LED's go out, and stay out, until Gate touches +12v again. We need to connect a 10k ohm resistor between Gate and Ground, so that the LED's are off unless power is applied to the gate, which will be +5v from Arduino pin 13 in the next example.

Schematic generated in SchemeIt, a free online schematic tool.

A platform for microcontrolled electro-mechanical, hydraulics, and pneumatics

2011-12-17T11:27:00.000-05:00

We've talked about Grid Beam as a inventors and experimenters dream before, but the more we dig into it, the more we get excited about it. If you missed our last article on the subject, Grid Beam is a system of easy to bolt together modular components made of metal, wood, or plastic. This system has been developed over the past 60+ years, starting with the original inventor, Ken Isaacs. He called the system "Living Structures".

Ideal for rapid prototyping, ease of disassembly, moving and reassembly. Fun for kids and adults. Solar mounts, wind turbines, hydroelectric, electric vehicles (cars, trains, submarines and more) are just some of the ways to use this system. We develop solutions using microcontrollers in a variety of electro-mechanical, hydraulic, and pneumatic applications and have many uses for grid beam as a platform for these solutions. Check it out!

How to build with Grid Beam

Isaacs, Ken - How To Build Your Own Living Structures (Free Download)

Open publication - Free publishing - More architecture

Arduino Robotics

2011-12-10T09:43:00.001-05:00

This book by John - David Warren and friends is one of my favorites. A good beginning in electronics and Arduino basics (easily ignored if you are experienced, but I suggest a overview anyway), then jumps into well documented meat and potatoes robotics, including wireless control, motor control, and sensors such as ultrasonic, IR, and tactile. Arduino Robotics by John-David Warren (Author), Josh Adams (Author), Harald Molle (Author)

New Arduino IDE 1.0

2011-12-10T09:41:00.001-05:00

A new programming interface, with some pretty major changes to available
routines, functions, and behavior in old functions. This one is important, check
it out at
http://tronixstuff.wordpress.com/2011/12/10/initial-review-arduino-v1-0-ide/

Join the Arduino discussions at http://tech.groups.yahoo.com/group/arduinohome/ .

Build your own Proto Shield for the Arduino

2011-11-19T06:53:00.001-05:00

The biggest issue with protoshields, is the Arduino funky pin spacing. Mike Cook has a way to make larger protoshields with plenty of prototyping space. Handier than breadboards, as the project is more "permanent". Mike has been helping us with our Arduino / Mitutoyo Micrometer project, and has a bunch of great Arduino tutorials on his website. Check them out, though you will need to do a bit of digging, as he has all kinds of fascinating stuff posted.

http://www.thebox.myzen.co.uk/Hardware/Arduino_Shield.html

http://www.thebox.myzen.co.uk/Tutorial/Introduction.html

http://www.thebox.myzen.co.uk/Workshop/Introduction.html

Digimatic SPC to Arduino

2011-10-13T21:01:00.003-04:00

12/2/2011 Update! We are now reading data from the micrometer, and stuffing the data into variables for further decision processing.

The Digimatic SPC protocol is a communications protocol developed by Mitutoyu, the big guns in Calipers, Micrometers, Dial Indicators, Scales and more. These devices have a data port that allows you to communicate with a microprocessor or microcontroller, for data logging and other measuring applications. We are still working on getting this working, and I'm posting the info I have in the hope others are helped, and may be able to help us.

Mitutoyo 05CZA662, Digimatic Cable, 40", With Data Switch for Coolant Proof Micrometers

Code, diagrams, and specs. - http://www.green-trust.org/digimatic/

Comments welcome!

Dennis Ritchie, RIP

2011-10-13T20:16:00.000-04:00

Dennis Ritchie, best known as the creator of the C programming language and co-creator of the UNIX operating system, has died at the age of 70 after a long, unspecified, illness. News of his death came from past collaborator, Rob Pike, in a message on Google+ which read: "I trust there are people here who will appreciate the reach of his contributions and mourn his passing appropriately. He was a quiet and mostly private man, but he was also my friend, colleague, and collaborator, and the world has lost a truly great mind."

http://www.h-online.com/open/news/item/Dennis-Ritchie-creator-of-C-and-more-has-died-1360480.html

Arduino VGA Display

2011-10-12T19:13:00.003-04:00

Our Arduino Micrometer Project is off and running. We have the speech module up and running, and now the VGA output module. It's a simple serial interface and only uses two i/o ports. We are using the PICASO QVGA/VGA/WVGA Graphics Controller from Sparkfun - http://www.sparkfun.com/products/10329

The µVGA-II(SGC) is a compact & cost effective drop in embedded graphics engine that will deliver stand-alone functionality to your project. The simple to use embedded commands not only control background color but can produce text in a variety of sizes as well as draw shapes in 256 colors while freeing up the host processor from processor hungry screen control functions. This means a simple micro-controller with a standard serial interface can drive the module with ease.

Making the Arduino talk, beep and sing

2011-09-24T08:05:00.001-04:00

A while back we built a Speakjet project for the Arduino. It allowed us to send sound effects, and program robotic speech to the speakers.

It wasn't terribly intuitive, programming it phonetically, so we added a text to speech ship, the TTS256. The Sparkfun shield we used wasn't designed for the TTS chip, so there weren't enough holes in the breadboard space to accommodate one end of the chip, and their traces are fragile where they suggest the modification.

We set out to design our own shield based on what we did and did not like about the Sparkfun unit. Well, we got scooped. The guys at Droidbuilder built a better mousetrap, er, TTS Speakjet Shield. It has almost all the features we wanted in our shield, but also includes a hefty price tag. It is, however, a worthy unit, and has excellent tutorials. Enjoy the show!

Speakjet Users Guide
TTS 256 Datasheet

Stepper Motor Project

2011-07-16T08:19:00.000-04:00

Since I'm waiting for some more parts to come in for my water level sensor I'm building for our aquaponics project, I thought I'd work on a stepper motor controller.

We use these controllers at work, and I wanted to get more experience with them. The ones at work are driven by a MS-Dos powered 486 computer, with a CIO-DIO24 interface card. These cards are obsolete, expensive ($159), and the PC's are old, bulky, and difficult to upgrade to newer hardware. The code was written in assembly and compiled basic, source code no longer available, and doesn't like newer, faster hardware.

The controller we are using is the SD200 Step Motor Drive Module. These are also obsolete, but still available. They retailed for about $135, but I've seen them online for less than $75.

There are 4 power connections. +5vdc and gnd for the controller, and +12-40vdc and gnd for the motor. Motor current may not exceed 2.5 amps. A low ESR, high ripple current 4700 μf capacitor is installed across the motor inputs, pins 13 & 18.

There are 3 inputs necessary, Enable, CW/CCW, and Pulse. Direction is controlled by applying high or low to the CW/CCW pin. Bring Enable high to activate the controller, and send a pwm signal to the Pulse pin.

There is a startup sequence necessary:

1. Bring Enable low
2. Apply 5vdc
3. Apply motor voltage
4. Bring Enable high

To shutdown the motor:

1. Bring Enable low
2. Drop motor voltage
3. Drop 5vdc

There is overcurrent protection. If there is a short, or the motor pulls more than 2.5 amps, pin 11 (enable) will need to be pulled low, or the shutdown/startup procedure will need to be run to reset. I've written two sub routines, called startup and shutdown, and a third called reset, that I can call from within my program. I've installed transistors on pin 12 & pin 18 so that I can enable/disable module and motor power from these subroutines.

The stepper motor I'm using is a Applied Motion HT17-073.

More details to come!

The Water Pressure Sensor

2011-07-05T07:46:00.000-04:00

This project uses a device called a differential pressure transducer to measure the water pressure at the bottom of the tank, and from that to calculate how full the tank is. Water pressure increases by about 9.8067kPa per meter of depth so a full tank 2m tall will have a pressure at the bottom of about 19.6134kPa above ambient atmospheric pressure. The "above ambient atmospheric pressure" part is important: it's not enough to simply measure the pressure at the bottom of the tank because varying climate conditions will alter the reading. That's why this project uses a "differential" pressure transducer that has two inlets. By leaving one inlet open to the atmosphere and connecting the other to the bottom of the tank the transducer will output the difference between the two, automatically compensating for varying air pressure and giving a constant reading for constant depth.

http://www.practicalarduino.com/projects/water-tank-depth-sensor

What is Gobetwino ?

2011-06-21T18:43:00.000-04:00

Gobetwino (go between o) is listening on the serial port, for "commands coming from Arduino, and in response it will do something for Arduino and possibly return something to Arduino.

Gobetwino defines a set of command types that can be used as templates to create actual commands. Arduino can ask Gobetwino to execute these commands, and return something to Arduino.

So what can Gobetwino do? Using the defined command types you can create commands in Gobetwino that Arduino can ask Gobetwino to execute. These commands can:

Start a program on the PC.
Start a program, and wait until it finishes, and tell Arduino it finished.
Send data to any windows program from Arduino, like it was typed on the keyboard.
Send email, optionally with an attached file.
Download a file from the internet.
Read a file and return data to Arduino.
Log data from Arduino to a file, with an optional timestamp.
Periodically check a POP3 mailbox for incoming mails and send commands from the mail to Arduino.
Get the time from the PC.
Get the date from the PC.
Ping a host or IP address.
Copy a file on the PC.

With combinations of these commands you can do things like:

Start any program on your PC, either directly or via an associated file type.
Start Excel, send data from Arduino directly into the Excel sheet, save the sheet and email it, without touching your PC.
Send e-mails to a POP3 mailbox and have Arduino react to the contents of the emails.
Log data directly to a CSV file on the PC, so the data can be used in spreadsheets or databases.
Download a file from the internet and have Arduino ask for a specific line of data from the file.

http://mikmo.dk/gobetwino.html

Hardware Random Number Generator

2011-05-28T22:31:00.000-04:00

I've been playing with various ciphers and encryption schemes, and needed a true random number generator to ensure secrecy. A Pseudo Random Number Generator uses a algorithm to produce a pseudo random number. If the algorithm can be determined, so can the outcome. A Hardware Random Number Generator uses a external event (sound, light, atmospheric noise, etc.) to seed the random number generator. For a neat project, and more info, see

http://robseward.com/misc/RNG2/

http://en.wikipedia.org/wiki/Hardware_random_number_generator

Dissolved Oxygen Sensor

2011-05-24T22:57:00.001-04:00

Looking for a way to detect dissolved oxygen levels? If you raise fish, this and a ph sensor are two important things to monitor (and of course, temperature), and an Arduino is the ideal platform to build upon. The Sensorex DO1200 ($139) outputs a <1mv - 54 mv signal indicating DO levels. Use
analogReference(INTERNAL1V1) to set the top of the input range to 1.1v.

Connect it to one of your analog pins. Very simple to read, just like a potentiometer.

Magnetic Core Memory Project - Retro Memory for your Arduino

2011-05-15T15:05:00.000-04:00

Magnetic core memory was the most widely used form of digital computer memory from its birth in the early 1950s until the era of integrated-circuit memory began in the early 1970s. Aside from being extremely reliable, magnetic core memory is an appealing technology because it is based on a very simple idea.

A core, a ring of magnetic material, stores one bit by the direction of its magnetization.

A magnetic core is a ring of ferrite material. It can be permanently magnetized either clockwise or anti-clockwise about its axis just as a vertical bar magnet can be magnetized up or down. We can then turn a magnetic core into a bit of digital memory by letting these two magnetization states correspond to 0 and 1.

It provides non-volatile storage.

The core needs no power to retain its data. In other words, core memory is a form of non-volatile storage like modern hard disk drives, although in its day it fulfilled the ‘high-speed’ role of modern RAM.

http://www.corememoryshield.com/

Dual water tank heater thermostat

2011-05-04T20:20:00.010-04:00

I am just finishing up a project at work, which requires two water tanks to be maintained at 180F. Each tank has twin 1500 watt, 240vac heating elements, each controlled by a SSR (Solid State Relay). My Arduino Mega 2560 reads two DS18B20 temp sensors (one in each tank), and maintains the temperature with a 5 degree window. I display both tank temperatures on a LCD, and control the color of two RGB LED's, blue for under temp, green for correct temp, red for over temp. The photo's are here. The following is the working code for the project.

#include <OneWire.h>
#include <DallasTemperature.h>
#include <LiquidCrystal.h>

// Connections:
// rs (LCD pin 4) to Arduino pin 12
// rw (LCD pin 5) to Arduino pin 11
// enable (LCD pin 6) to Arduino pin 10
// LCD pin 15 to Arduino pin 13
// LCD pins d4, d5, d6, d7 to Arduino pins 5, 4, 3, 2
LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2);

int tank1BLED = 37;
int tank1GLED = 39;
int tank1RLED = 41;
int tank2BLED = 43;
int tank2GLED = 45;
int tank2RLED = 47;

// Data wire is plugged into pin 8 on the Arduino
#define ONE_WIRE_BUS 8

// Setup a oneWire instance to 
//communicate with any OneWire devices
OneWire oneWire(ONE_WIRE_BUS);

// Pass our oneWire reference to Dallas Temperature. 
DallasTemperature sensors(&oneWire);

// Assign the addresses of your 1-Wire temp sensors.

DeviceAddress tank2Thermometer = { 0x28, 0x46, 0x3C, 0x16, 0x03, 0x00, 0x00, 0xA9 };
DeviceAddress tank1Thermometer = { 0x28, 0xDF, 0x21, 0x16, 0x03, 0x00, 0x00, 0x1E };

int tank1 = 31; // heater control pins
int tank2 = 33; // heater control pins

float tank1temp = 0;
float tank2temp = 0;

void setup(void)
{
  // Start up the library
  sensors.begin();
  // set the resolution to 10 bit (good enough?)
  sensors.setResolution(tank1Thermometer, 10);
  sensors.setResolution(tank2Thermometer, 10);
  
  
  
  pinMode(tank1BLED, OUTPUT); // Tank LED's
  pinMode(tank1GLED, OUTPUT);
  pinMode(tank1RLED, OUTPUT);
  pinMode(tank2BLED, OUTPUT);
  pinMode(tank2GLED, OUTPUT);
  pinMode(tank2RLED, OUTPUT);
  
  digitalWrite(tank1BLED, HIGH); // set Tank LED's off
  digitalWrite(tank1GLED, HIGH);
  digitalWrite(tank1RLED, HIGH);
  digitalWrite(tank2BLED, HIGH);
  digitalWrite(tank2GLED, HIGH);
  digitalWrite(tank2RLED, HIGH);
  

lcd.begin(20,4); 
// columns, rows. use 16,2 for a 16x2 LCD, etc.
lcd.clear(); 
// start with a blank screen

pinMode(tank1, OUTPUT); // Tank heaters
pinMode(tank2, OUTPUT);

}

void printTemperature(DeviceAddress deviceAddress)
{
  float tempC = sensors.getTempC(deviceAddress);
  float t1tempC = sensors.getTempC(tank1Thermometer);
  float t2tempC = sensors.getTempC(tank2Thermometer);
  if (tempC == -127.00) {
lcd.print("Error");
} else {
// lcd.print(tempC);
// lcd.print("/");
tank1temp = (DallasTemperature::toFahrenheit(t1tempC));
tank2temp = (DallasTemperature::toFahrenheit(t2tempC));
lcd.print(DallasTemperature::toFahrenheit(tempC));
  }
}

void loop(void)
{ 
  delay(2000);

  sensors.requestTemperatures();
  
lcd.setCursor(0,0);
lcd.print("Tank 1: ");

printTemperature(tank1Thermometer);

lcd.setCursor(0,1);
lcd.print("Tank 2: ");

printTemperature(tank2Thermometer);



if (tank1temp <=178.9)
{
  digitalWrite(tank1, HIGH);
  digitalWrite(tank1BLED, LOW);
  digitalWrite(tank1GLED, HIGH);
  digitalWrite(tank1RLED, HIGH);
}

if (tank1temp >= 179 && tank1temp <= 181.9)

{
  digitalWrite(tank1GLED, LOW);
  digitalWrite(tank1RLED, HIGH);
  digitalWrite(tank1BLED, HIGH);
}

if (tank1temp >= 182)
{
  digitalWrite(tank1, LOW);
  digitalWrite(tank1RLED, LOW);
  digitalWrite(tank1GLED, HIGH);
  digitalWrite(tank1BLED, HIGH);
}




if (tank2temp <=178.9)
{
  digitalWrite(tank2, HIGH);
  digitalWrite(tank2BLED, LOW);
  digitalWrite(tank2GLED, HIGH);
  digitalWrite(tank2RLED, HIGH);
}

if (tank2temp >= 179 && tank2temp <= 181.9)

{
  digitalWrite(tank2GLED, LOW);
  digitalWrite(tank2RLED, HIGH);
  digitalWrite(tank2BLED, HIGH);
}

if (tank2temp >= 182)
{
  digitalWrite(tank2, LOW);
  digitalWrite(tank2RLED, LOW);
  digitalWrite(tank2GLED, HIGH);
  digitalWrite(tank2BLED, HIGH);
}




}

Sine, cosine, and tangent (the dreaded T word)

2011-05-01T15:14:00.000-04:00

Why does trigonometry sound so scary? Often in the world of physics, and when the real world comes crashing into the lab, we need to use sine, cosine, and tangent in our calculations for having a way of relating the angles in a triangle to the lengths of the sides. Here is a simple tutorial that will act as a refresher if you have forgotten, or a brand new look at a useful set of equations if you never took trig.

http://www.physics.uoguelph.ca/tutorials/trig/trigonom.html

What is a Sprout Board?

2011-04-24T08:50:00.001-04:00

A sprout board in a basic description would be a motherboard or breakout board. It allows a micro controller to dock with it as well as a accessory shield. It also offers a host of onboard components as well as external connectivity options. The sprout board is designed to allow for flexibility and stability in a single package. Designed for actual use in everyday gadgets we have placed the most important and desired components onboard ready for easy use.

But the sprout board is more than just a circuit board. It is a complete package offering flexibility and applicability in what we are producing. We offer chassis for varied application as well as complete software ready for use. This allows mixing and matching of components and accessories to create a broad verity of real use projects with minimal effort.

http://www.sproutboard.com/

Erector Sets for Big Kids

2011-04-09T18:09:00.001-04:00

We have come across two companies that make structural modular pieces for mechanical, electrical, hydraulic and pneumatic controls and more. Ideal for making Arduino powered equipment and mechanisms. These are the industrial versions of Erector Sets and Lego's. Let's go build something cool!

http://8020.net/

http://www.itemamerica.com/

Arduino Mega with LCD Raffle

2011-04-06T20:34:00.002-04:00

We are raffling off a Arduino Mega 2560 with a 4 line x 20 character White on Blue LCD. Tickets are $5 each, and the raffle ends April 30th. Ticket sales benefit Water Purification units for developing nations and disaster relief.

Arduino Mega 2560

20 x 4 White on Blue LCD

Monitoring current and voltage with the TI INA210

2011-03-27T11:17:00.001-04:00

This week we received a INA210 from Texas Instruments. Officially it's a "Voltage Output, High/Low-Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor". It allows us to monitor the amps flowing through the shunt, and to display the "right now" amp consumption (or production), volts, watts, and watt hours (with some simple arduino programming).

Combine this with one of our calibrated shunts (100a, 500a, and 1000a), and you have a powerful method of monitoring the power produced by a solar panel, consumed by an inverter or other dc load. Build your own watt or watt hour meter.

We will be working with this chip in a number of future projects.

Monitoring voltage of a dc battery supply

2011-03-20T15:25:00.001-04:00

Since we are involved in off grid solar power systems, we have a need to monitor battery voltage. The Arduino can do this easily with a simple voltage divider. With some simple mods, we can control loads, generators, or notifications based on battery voltage.

To read a maximum of 20vdc, R1 should be 3k ohm, R2 should be 1k ohm, and the code would be as follows:

/*
DisplayMoreThan5V sketch
prints the voltage on analog pin to the serial port
Do not connect more than 5 volts directly to an Arduino pin.
*/

const int referenceVolts = 5; // the default reference on a 5-volt board
//const float referenceVolts = 3.3; // use this for a 3.3-volt board

const int R1 = 3000; // value for a maximum voltage of 20 volts
const int R2 = 1000;
// determine by voltage divider resistors, see text
const int resistorFactor = 255 / (R2/(R1 + R2));
const int batteryPin = 0; // +V from battery is connected to analog pin 0

void setup()
{
Serial.begin(9600);
}

void loop()
{
int val = analogRead(batteryPin); // read the value from the sensor
float volts = (val / resistorFactor) * referenceVolts ; // calculate the ratio
Serial.println(volts); // print the value in volts
}

This example was based on info in Arduino Cookbook (Oreilly Cookbooks)

Simple Voltage Dividers

2011-02-12T10:45:00.007-05:00

A Voltage Divider is a simple circuit for dividing a higher voltage into a lower voltage without cumbersome transformers, etc. The example shows the proper values of two resistors (in ohms) for obtaining 12v from 120v. Using the formula and calculator below, you can adjust the voltage in, and resistance values, to get the output you desire.

If Vin = 120v, R1 = 9000 Ohms, and R2 = 1000 Ohms:

Vout = (R2 /(R1 + R2))* Vin

Vout = (1000 / 9000 + 1000)) * 120v

Vout = 12v

http://www.green-trust.org/voltage_divider/ (Calculator)