TL;DR: Get code here: https://github.com/marcmerlin/aiko_pebble_v2
Note, you will need the LiquidCrystal_SR_LCD3 driver from the NewLiquidCrytal Library.
You will also need the Aiko Library: https://github.com/geekscape/aiko_arduino .
Pebble v2 requires at least the IDE 0.23 (untested) but 1.0 or better is recommended. The code is of course arduino 1.0 compatible.
At the LCA 2012 Arduino Miniconf, we got to build a new toy, a Freetronics Pebble v2 (schematics here). This was a refresh of the Pebble V1 (schematics here) which was the target of the very first arduino miniconf I missed in 2010.
This new Pebble had even more hardware to program against and was a much more compact design due to the use of a bunch of SMT parts (actually there are 2 arduinos on the board, one is dedicated to usb/serial communications, removing the need for an ftdi chip).
Like good hacking projects and conferences, the design and software were improved until the last minute, and Andy worked all night before the conf to get us his demo code (along with bits from Luke and others).
Andy wrote the very cool aiko event handler for arduino. You give it a list of callback functions and it'll do its best to call them on the interval you gave it (interval in milliseconds). For arduino folks, with Aiko, code looks like this:
void setup(void) {
Serial.begin(DEFAULT_BAUD_RATE);
// Call LCD init early so that others can write to it.
lcdInitialize();
Events.addHandler(clockHandler, 1000);
Events.addHandler(lightHandler, 1000); // Aim for 250 ms
Events.addHandler(rotaryEncoderHandler, 100);
Events.addHandler(serialHandler, 30); // Sufficient for 38,400 baud
Events.addHandler(temperatureHandler, 1000); // Aim for 250 ms
Events.addHandler(touchPanelHandler, 250); // Aim for 50 ms
Events.addHandler(rgbLedFadeHandler, 10); // Can run slower.
// Call LCD last so that it can display variables that just changed.
Events.addHandler(lcdHandler, 1000); // Aim for 100 ms
}
void loop(void) {
Events.loop();
}
So Andy got us working code to test our hardware, but of course it wasn't fully optimized (hell, code never is). So, that gave me a chance to do some arduino programming to see what could be improved. It was a good learning experience.
After a bunch of work, here is what I was able to do:
I happened to have RGB LED demo code I had taken a while to write over Xmas (nice transitions that I went through the trouble of writing so they would work with an Aiko event handler), so I did a bit more hacking to refine the code and plugged it in.
The rotary button was being polled every millisecond to catch which was it was turning. First I figured that every 5ms was probably enough, but thanks to sample code from Brett Downing, I was able to write a handler using hardware interrupts on input pin state changes (something I knew nothing about, so it was a good learning experience).
Then this brings us to the LCD handler. I had some grand view of writing a popup menu that would let you configure the code at runtime, but that meant a lot of LCD code. I knew arduino had a nice LiquidCrystal library, but it did not work with the shift register setup in the Pebbles. Long story short, I wrote a plugin for the Pebble/LCD3Wires shift register setup in the Pebble. This demo requires this new library (LiquidCrystal_SR_LCD3) to do its work.
The 4th line shows the color that the RGB LED is changing towards
LED 6 means that the color change delay factor is 6 (lower means faster color changing)
3 in LED 6/3 is by how much the color brightness is reduced (clips the color values so that they arne't too bright, mostly useful in dark rooms or when taking pictures).
LCD 80 is the analog PWM value for the LCD backlight (higher is brighter).
A few custom characters are displayed to show use of the custom character support brought by LiquidCrystal_SR_LCD3
