LCD Gauges
10-08-2012, 06:45 PM
This thread started on the "other" board, but for those that don't venture over there, here's a solution to adapt the FFR supplied gauges (Autometer) to different voltage senders.
One other member had luck with just a resistor in series with the oil sender signal wire. He used a 120 Ohm resistor (at R1), as opposed to a 150 Ohm in my test setup.
I recommend using a variable potentiometer instead of a dedicated value so that each system can be calibrated for tiny variances. At 2.0 volts, the gauge should read 64 PSI
when connected to the LS3, 5 Volt sending unit.
http://www.youtube.com/watch?v=s3Eqm-Ick08&sns=em
12255
0.700 VDC = 0 PSI
2.000 VDC = 60 PSI
2.500 VDC = 95 PSI
Current limiting resistor = 150 Ohm
Diode in series with input signal from oil sender (drops 0.600 VDC) to eliminate the offset.
Total current (at max deflection) = 11.6 mAmps
Total power = 58 mWatts
Approximate cost to convert = $2.00
One other member had luck with just a resistor in series with the oil sender signal wire. He used a 120 Ohm resistor (at R1), as opposed to a 150 Ohm in my test setup.
I recommend using a variable potentiometer instead of a dedicated value so that each system can be calibrated for tiny variances. At 2.0 volts, the gauge should read 64 PSI
when connected to the LS3, 5 Volt sending unit.
http://www.youtube.com/watch?v=s3Eqm-Ick08&sns=em
12255
0.700 VDC = 0 PSI
2.000 VDC = 60 PSI
2.500 VDC = 95 PSI
Current limiting resistor = 150 Ohm
Diode in series with input signal from oil sender (drops 0.600 VDC) to eliminate the offset.
Total current (at max deflection) = 11.6 mAmps
Total power = 58 mWatts
Approximate cost to convert = $2.00