Light system for Bicycle

1. Outcome

2. Components

Left Arrow/Right Arrow by Potentiometer; Slow Down by Light Sensor

3. Circuit and Code

download the eagle file of mainboard
download the eagle file of LED charliePlexing
download the c code for Attiny44

CharliePlexing is a way to control more directional components with limit number of out out pins; n Pins can cantrol up to n*(n-1) components. LED is typical for this methord; by adding diode to each sensor/components, charliePlexing can be applied to non-directional sensor/components.
Neil's code and example is good to start with.

Board and Code from Class Achive

techniques this week deal with charlieplexing, H-bridge, OPAMP, etc. CharleiPlexing is creating matrix to control more output with limited pins from microcontroller; And there's a tutorial on motor control in tutorial session.
led charlieplexing
speaker
DC motor
Stepper Motor