This project is an exposure timer for diy pcb making for a home made ultraviolet light exposure box.
Exposure time can be set in 10 second increments. The set time is saved in EEPROM and used as the next default value.
The timer is built on a picaxe 08M2. It uses an inexpensive 16x2 character LCD and connects to that using the I2C bus and an I2C I/O expander chip.
User input is via a rotary encoder and its push button.
A more detailed description with schematic and code are available on my website at http://justaddelectrons.com/blogi/pcb-exposure-timer-with-picaxe-microcontroller-and-lcd-display