430man Evolution has a pretty simply underlying idea: A chain of LEDs that can be triggered at multiple points.
Floating pins capture touch events and a light pulse propagate through the sculpture. Thanks to the ultra low power feature of the MSP430 the system of 8 MCUs only consumes about 50uA in standby and should last a while on a single CR2032 battery.
The chain is divided into independent subsections, consisting of:
- 2 input pins detect touch events and receive pulses from its neighbor
- 2 output pins to propagate pulses to its neighbor
- 6 SMD 1206 LEDs
- 100nF decoupling cap (important if you want to avoid brownouts.)
- 100mil / 2,54mm pitch headers
- Coated repair wire for the connections
- R and C for the reset circuit
Programming is straight forward too. The chain can be triggered from the “left” and “right”. So two independent shift registers are used to keep track of the pulses. To output the both registers are XORed and displayed.
Tip: Saving resistors and energy is easy. Use the build-in timer with the PWM feature to control brightness of the LED without actually wasting energy. 5 more lines of code and the world is a greener place.
Tip: TI’s IDE CodeComposer Studio has two handy tools build in. First is Grace, a graphical configuration engine that allows you to set up I/O’s, Timer, PWM in no time. And at compile time there is the ULP Advisor that checks your code against ULP coding rules to help you minimize energy consumption.
Disclaimer: No perfectly good MCU’s got hurt in this project. All devices used in this project have been damaged or are outdated revisions that would have otherwise been scrapped.