Now that you’ve built the project, it’s time to try it out!
Point and shoot. That’s pretty much it, as A.C.I.D. will startup and begin emitting combinations of the three tones depending on the light it receives.
Light sources, like screens and even street lights, work particularly well but with enough light and an appropriate lens, ACID can discriminate between medium sized objects at a good distance.
To calibrate the device, point it at something white and hold the calibration switch closed. After a few moments you’ll hear a few notes played to let you know the calibration is complete. ACID has two calibration settings, for high- and low-light conditions, which is useful when using “headlight” LEDs that may have a slightly biased hue. You may want to recalibrate whenever lighting changes. The process only takes a few seconds and the results are stored in the on-board EEPROM (non-volatile memory).
The source code contains plenty to play with, and is commented throughout–though I’ll admit that some parts have a bit of voodoo determined (let’s say) empirically. The SPI header allows you to use the results of colour sampling in other projects, as it will output data reflecting current levels whenever they change.
Hook it up to a servo motor, create a smarties-sorting machine, use it to send tweets about the weather… however you use A.C.I.D., I’d really love to hear about it.