Automotive Isolation Box
2012-09-03 01:47 by IanThis is a brief construction log of the barrier that sits between the computer and the hostile electrical environment found in a car.
- Needs to supply a regulated 5v to the computer, with a minimum of ripple.
- Needs to be able to actuate at least 4 relays for activating various things in the vehicle.
- Needs to be able to sense for the presense of voltage at four separate points.
Inside of completed box. The top perf board contains a digital audio switch, 4 optocouplers, and a voltage monitor circuit to ensure the PSU comes up in the correct state. Since this board also has the header for the external connectors, the relay header (with inline resistors) connects here as well.
Completed box with computer interface cable attached. The three audio jacks will run to the radio (input), a non-committed input, and the stereo (as the common output). There is a third possible input, but it is connected internally via the DB15HD cable.