Saturday, August 7, 2010

Arduino - The Documentary

Here is the Trailer for the upcoming documentary:

TRAILER Arduino: The Documentary (available on HD) from gnd on Vimeo.

Remote Control Lawnmower

This instructable will show you how to make your Arduino into an R/C interface that you can use for just about anything requiring remote control. I will also show you how I built an R/C lawnmower using my Arduino, a cheap R/C transmitter and receiver pair, and a couple of electric-wheelchair motors from Ebay. I have used this interface to control anything from basic LED's to Bipolar stepper motors, mini-robots, lifeless R/C cars from the thrift store, and even a 100lb lawnmower (all with appropriate motor controllers). It is very flexible and easy to change and very simple to set up.

Arduino R/C Lawnmower (painted) - More DIY How To Projects

Friday, August 6, 2010

Control your Christmas Lights

Want them to react in different patterns, to music, or even remotely controlled? There are ideas galore here:

Christmas Lights to Music Using Arduino - More DIY How To Projects

Stepper Motors - scavanged from old floppy drives


This page shows two examples on how to drive a unipolar stepper motor. These motors can be found in old floppy drives and are easy to control. The one we use has 6 connectors of which one is power (VCC) and the other four are used to drive the motor sending synchronous signals.

The first example is the basic code to make the motor spin in one direction. It is aiming those that have no knowledge in how to control stepper motors. The second example is coded in a more complex way, but allows to make the motor spin at different speeds, in both directions, and controlling both from a potentiometer.

The prototyping board has been populated with a 10K potentiomenter that we connect to an analog input, and a ULN2003A driver. This chip has a bunch of transistors embedded in a single housing. It allows the connection of devices and components that need much higher current than the ones that the ATMEGA8 from our Arduino board can offer.

See for more info.

Stepper motor source -

Thursday, August 5, 2010

Solar Power your Arduino with the Freeloader Pico

The ideal power source for your Arduino projects. It looks just like USB power to the Arduino, no special shield necessary. A bargain at $30.

Freeloader PICO is a compact and lightweight solar charger designed for people on the move!
Using advanced solar cell and lithium ion battery technologies, PICO will charge its internal battery in double quick time. It then takes only 30 minutes to deliver its power to give a mobile phone 35 hours, iPod 14 hours, GPS 1 ½ hours etc etc.

Freeloader PICO is supplied with four connection tips, a master cable and a comprehensive user manual. PICO can also directly connect to any device supplied with a USB charge / sync cable, giving virtually unlimited connectivity.

PICO can be powered from both its own solar cell or from connection to a PC or lap top (cable supplied).

PV tracking systems and photosensors

The Arduino, matched with a couple of photosensors, and a gear motor, makes a inexpensive solar tracking system:


Photocells are sensors that allow you to detect light. They are small, inexpensive, low-power, easy to use and don't wear out. For that reason they often appear in toys, gadgets and appliances. They are are often referred to as CdS cells (they are made of Cadmium-Sulfide), light-dependent resistors (LDR), and photoresistors.

Photocells are basically a resistor that changes its resistive value (in ohms Ω) depending on how much light is shining onto the squiggly face. They are very low cost, easy to get in many sizes and specifications, but are very inaccurate. Each photocell sensor will act a little differently than the other, even if they are from the same batch. The variations can be really large, 50% or higher! For this reason, they shouldn't be used to try to determine precise light levels in lux or millicandela. Instead, you can expect to only be able to determine basic light changes

For most light-sensitive applications like "is it light or dark out", "is there something in front of the sensor (that would block light)", "is there something interrupting a laser beam" (break-beam sensors), or "which of multiple sensors has the most light hitting it", photocells can be a good choice!

For details on photo sensors including schematics and code, see

For details on a cds pv tracking system, see

Wednesday, August 4, 2010

Home-Made Thermostat

By Avatar-X

If you've ever looked into automating the temperature control in your home, you will quickly have found out that it's not a cheap prospect. The cheapest network-connected thermostat I could find was $450 US, and that's just a start. So, I decided to build my own thermostat, using an Arduino and some other components.

My thermostat directly controls my HVAC unit, which has a standard four-wire interface. One wire is common, and there is one wire for each of Heat, Cool (A/C), and Fan. I'm using an LM35 to measure the temperature, three relays to connect the HVAC, a nice 20x2 LCD display for status, and some buttons and switches, all mounted into a project box. Since the Arduino has a built-in USB interface, I use that to provide status back to the computer, and allow the computer to issue commands.

New toys - Arduino Catalyst Pack

I received my clickbank deposit today, so I paid the rent and car insurance, and decided to pamper myself a little bit. I ordered a add-on pack of components for my Arduino. A nice selection of resistors, capacitors, transistors, motors, LED's, diodes, piezo buzzers, switches breadboards, and more, for only $30 (included S&H). What a deal, and will be lots of fun. See the whole package at Arduino catalyst pack.

Power Over Ethernet for Arduino

When connecting an Arduino to an Ethernet network it can be really annoying that you need to run two cables to it: one for the LAN, one for power. It's particularly annoying if you're going to be putting the Arduino in some strange location with no easy access to power. Wouldn't it be nice if the Arduino could just draw power from the network connection?

Tuesday, August 3, 2010

The Solar Powered Arduino

One of the things I wanted to play with was powering my Arduino with solar. I found a solar charger shield for about $10 that only requires a Li-ion (NiMH would also work) battery and a 5v PV cell. It also allows USB charging.

Solar Thermal Differential Controller

A thermal differential controller is what is used to control the pump between the solar panel and hot water tank. It senses when the solar panel is hotter than the tank and starts up the pump so that the water can get warmed up. When the panel cools off, the controller turns the pump off so it doesn’t cool down the tank.

This is a 2 part series explaining the concept and process, but the implementation with a Arduino seems unfinished.

Part 1 -

Part 2 -

Discussion Thread -

Monday, August 2, 2010

My First Program - Fade LED

The first thing I did when I got my Arduino Duemilanove from Hacktronics was of course open the box. Inside was the Arduino, a solderless breadboard, five 270 ohm resistors, six LED's in assorted colors, a micro pushbutton switch, an assortment of colored jumpers, a USB cable, and a bubblegum flavored dum-dum ($50 delivered).

I downloaded the Linux version of the Arduino software.

I plugged in the USB cable. The board comes preloaded with the blink sketch, and sure enough, it started winking at me. Ok, big deal, that's boring. So I connected Gnd and Digital pin 9 to the breadboard. Pin 9 goes to the + on the LED (anode), the - of the LED (cathode) connected to the 270 ohm resistor, and the other end of the resistor to Gnd. Then I loaded the Fade sketch as follows:
int ledPin = 9;
// LED connected to digital pin 9

void setup() {
// nothing happens in setup

void loop() {

// fade in from min to max in increments of 5 points:
for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5) {
// sets the value (range from 0 to 255):
AnalogWrite(ledPin, fadeValue);
// wait for 30 milliseconds to see the dimming effect
delay(30); }

// fade out from max to min in increments of 5 points:
for(int fadeValue = 255 ; fadeValue >= 0; fadeValue -=5) {
// sets the value (range from 0 to 255):
analogWrite(ledPin, fadeValue);
// wait for 30 milliseconds to see the dimming effect

Now I have a LED that fades in and out :-)
Now on to bigger and better things.

Automotive OBDII Monitor and Control

Interfacing a Arduino to your car or truck computer allows you to monitor the performance of your vehicle and watch for and explain trouble codes. You could build your own custom gauge display, monitor fuel consumption, turbo boost pressures and more. There's a bit of interfacing to do, but there is a chip that talks most of the different protocols in use by the various manufacturers. A good start on the process is explained at, and details on the interface chip can be found at For more details on OBD-II, see

Pneumatic Controls

Need to control a pneumatic cylinder? We use low voltage compressed air cylinders at work, and that gave me the idea for some cool steampunk style pneumatic controls. The Arduino can use a relay to activate the solenoid on the compressed air cylinder, extending the cylinder and retracting it. This could be used to open and close doors, robotic arms, and many other uses. A source of compressed air, and 12v (or 24v) for the solenoid would be needed.

Sunday, August 1, 2010

The Arduino Web Server

One of my goals for the weather station and energy monitor is to be able to access it remotely. The best way I figure is the universal front end, a web browser. this requires me to interface a ethernet interface, web server software, and logging cabaility to my microprocessor applications. Well, the hardware already exists, and a few folks have worked hard on the software, so implementing this solution is close to plug and play. See

VW Diesel Governor Control

Although this project is for a firewood processor, it would work similarly for a diesel generator. A Arduino processor controls a servo connected to the throttle linkage. Run the VW (or Mercedes, Kubota, etc.) Diesel engine on used filtered vegetable oil, and you have almost free electricity. Belt drive a 1800 rpm alternator off the engine, or if you are really handy, direct drive off the transmission bell housing.

Closed loop PID control of a VW diesel engine with an Arduino microprocessor. Throttle actuation accomplished with a stock RC servo motor. See for Arduino source code and schematics