Air pump circuit modifications

Friday, January 7th, 2022

The team assembled the air pump control circuit, as described in the electrical design. However, the transistor used as a switch stopped working! To confirm the GPIO pin on the Jetson Nano was working correctly, the voltages were measured using a DMM. In the on state, the collector voltage appeared to be greater than the base voltage (strange).

After some more measurements, the team discovered that the air pump was drawing more current than initially thought, exceeding the maximum specification of the transistor. A second configuration, using a Darlington pair was tested, and seemed to work!

Later, a current spike killed a second transistor. The team decided it would be more reliable to use a relay switch.