Arduino Pazzia

I'm going to start posting my microcontroller adventures here, since these is an appropriate place to do it.

So about a month ago, I bought an Arduino from the Maker Shed, since it was on sale.



The Arduino is a broadly open-source project. The circuit board is open source, and available in just about any format, in several different types. The software is open source, and even includes a friendly and easy to learn development environment.



The core chip in the Arduino family of boards is the Atmel ATmega. The ATmega is an 8-bit microcontroller family. It's both low-power and high-performance. It's available in several versions with different amounts of flash and RAM on-board. The board I have uses the ATmega 328P, which has 32KB of flash and 2KB of SRAM.

Almost all of the pins on the chip are multipurpose IO pins. Some of them can be analog inputs, digital inputs, digital outputs, or PWM outputs with 8 bits of PWM control.

I've been playing around with the analog and digital output side with some LEDs. I did the usual Arduino "hello world" program, which is just to connect a single LED to an output and ground, and make it blink. (Most of the Arduinos actually have an LED and resistor on one output for this sort of thing)

I bought a dozen high-brightness green LEDs, and connected 6 of them up to outputs on the Arduino.

• I got them doing the Cylon/Knight Rider LED sweep.
  
• I got them doing a sine wave (at several frequencies and phases)
  
• I got them doing a cool analog sweep back and forth
  
• I made them into a 60-second binary timer. Tick tick tick tick...

I bought a couple RGB LEDs, which I already posted about. After a great deal of experimenting, I found a mix of resistors that got the colors balanced and workable. I've got one of them running a constant color changer, slowly sweeping each of the colors through a 100-step sine wave, with three different frequencies (all relatively prime) so that it eventually sweeps through all 24 million color combinations. Some of the stuff it does is really pretty.

I'm going to hook up the second LED, and have two! I also ordered some tiny LED modules that have on-board power control and their own tiny processor to run scripted light shows. They're controlled by the Arduino via I2C, which the Arduino environment supports natively.

I also ordered some real common-cathode RGB LEDs to play with. Much easier to deal with then these cheap-ass Radio Shack common-anode LEDs.

I've also found a 4-channel I2C controlled DAC with current controlled outputs, etc. It'd be great for an even cheaper Arduino-controlled LED light show sort of thing. I need to get some samples and see how cheap and small I can build such a thing.