The Color Meter

John Peterson
contact102 [at] saccade.com
June 2010

Honorable Mention
DesignStellaris 2010

The Color Sensor is a simple to use, low cost tool for getting color readings from both reflected and emitted light.  It gives readings in multiple intuitive formats, both on a built-in LCD display, and also on a larger web page available over a local network.  The Color Sensor is lightweight and portable, making it easy to use in a variety of environments.

The Color Sensor uses the TI/Stellaris LM3S9B96 MCU to control all operations.  This was a 32-bit ARM chip, with a unique ROM containing a multi-tasking OS and device drivers. This MCU has since been phased out by TI. The MCU communicates with the color sensor over using the built-in I2C interface, the LCD display using a modified SPI protocol, the Ethernet using the built-in Ethernet controller, serial IO for system debugging and number of switches and indicators via parallel I/O.

A detailed write-up [PDF, 281K] with schematics is available. The project didn't quite pan out as I'd hoped. There are some lessons learned in the process of completing the project.