Electronics Burn-in Fixture

First Wave Technologies, Inc was designing a second generation medical device, and wanted the initial quality to be perfect.  Looking at the data from the launch of the first generation product, most of the initial quality problems were due to electronics failures and connectors.  I designed and built a electronics burn-in fixture to exercise each board continuously for 24 hours.  Electronic failures occur due to premature component failures and thermal cycling, with the most stressful times being startup and shutdown of power.  Boards were put through a functional tester, and then put into this burn-in tester.  The fixture was Arduino based, and would turn on the power to the board, run through initialization, charge the battery, shutdown, and then repeat.  In order to not overcharge the battery, we put in a voltage monitoring circuit based on a voltage divider monitored by the Arduino analog input, and turned on a relay to put a power resistor across the battery when the voltage exceeded a set amount.  When the battery voltage dropped below a lower voltage threshold, the Arduino would open the relay and take the power resistor out of the circuit.  A thermistor monitored battery temperature as well.  The fixture was designed to be scalable and low cost.  We ended up scaling the board burn-in fixture to equal 1 day’s worth of production.  This fixture was a key component of a successful product launch.