How do I hook up an external sensor?

[McRat]

If 0 PSI = 7 ohms and 120 PSI = 160 ohms, how do I read that in using EFILive?

[Redline Motorsports]

I think you need to somehow get this converted to a voltage reading. Can you find a Autometer pressure sender that works from 0-5 volts? That would be key as FS works in those voltage ranges.

Howard

[joecar]

As Howard said, can you translate those values to 0-5 volts...?

[McRat]

I know there is a way to turn ohms into volts, but electricity and I have a mutual non-aggression pact.

I agree that I will not screw with it, and it agrees not to send me to the Burn Ward of the hospital again! :D

Basically the circuit that inside an ohmmeter will do it, but I do not know how to look it up.

I went to Radio Shack and they said use a resistor. Nope. Even at 20,000 ohms, the voltage stayed at 12v regardless of what the pressure was.

I would like to use these $25 VDO pressure senders that go 0-150 PSI, but they are only Ohm based.

[McRat]

OK, I think I figured it out.

[Ira]

A 300 ohm resistor to 12V and one side of the sensor, the other side of the sensor to ground and connect the middle to EFIlive should do it.

Ira

[Redline Motorsports]

Post results. Good info.

Howard