Audio Switch Matrix

Designed hardware for a switch matrix preamplifier system for distributing high quality audio signals from 16 independent sources (CDs, Tuners, etc) into a maximum of 128 rooms. Each source could be selected and controlled (play, pause, stop, etc) from any room. Subsequent rooms selecting the same source could only listen to the audio without controlling the source. Specified and implemented an ASCII control language, written in ‘C’ for the H8 processor, allowing the unit to be monitored and controlled via its RS232 port.

Learning Infra Red Handset

Specification, design and test of hardware and software for an infra-red remote control handset for controlling domestic HiFi and TV equipment. The handset was capable of receiving, storing and re-transmitting infra-red codes from other handsets, using an intelligent 3 stage "capture, decode and compress" learning algorithm to decipher the incoming data. Hardware was based on a Z8 processor with encoded data stored in EEPROM via an I2C serial bus interface. Software was optimised for minimum code footprint and was written mainly in 'C' with time critical interrupts routines written in assembler.

Central Heating Room Monitor

Designed electronics for a low cost room monitor unit for the high volume (30K/year) domestic Outside Temperature Compensated (OTC) central heating controller market. The low unit and installation cost targets inspired the development of an innovative 2-wire power/data multiplexed signal protocol. The design utilised low power CMOS analogue circuits to monitor the actual and desired room temperatures, the status of a 3 position day/night/auto selector switch, and a 'boost' pushbutton, and communicated the data via analogue voltage levels on the 2-wire bus at the request of the OTC controller.