RS-232 interface module, with 9 inputs and 9 outputs. Uses an AVR ATmega8 microcontroller.
Home power consumption measuring unit, with AVR

Measures the power consumption by counting LED pulses from the home fuse box. Measurements can be read via a serial interface, uses the AVR ATtiny2313 microcontroller.
Serial port I/O module with 11 inputs — AVR

RS-232 input module, with 11 inputs. Rebuild of previous RS-485 module. Uses an AVR ATtiny2313 microcontroller.