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### Topic: problem with the gaugue (Read 975 times)previous topic - next topic

##### Jun 29, 2013, 04:20 pm
Hii to all A few months ago I started doing a car simulator with real gauges but i have problems with the fuel and oil gauge , how i conect this gauges to the arduino?? http://subefotos.com/ver/?b595c5e2c23fde07245e019ded626cf9o.jpg

#### groundFungus

#1
##### Jun 29, 2013, 04:52 pm
I would think that you connect Arduino analog input to the S (sender) terminal through a voltage divider to bring the 0-12V sender output down to the 0-5V for the Arduino ADC.

#### jackrae

#2
##### Jun 29, 2013, 08:30 pmLast Edit: Jun 29, 2013, 08:32 pm by jackrae Reason: 1
The gauges are monitoring the voltage applied to the S terminal.  Before you connect to the arduino you need to establish what voltage needs applying to the S terminal you get the gauge to span correctly (0% 50% and 100%) and you also need to measure how much current the S terminal demands at each of these points.   Once you have these two tables of information, publish them here and you will then be advised on the next step.

I suspect the voltage linearity will be very non-linear and the current demand will be greater than the arduino can deliver without using a buffer transistor.

#### groundFungus

#3
##### Jun 29, 2013, 08:46 pm
Sorry, I misunderstood the intent.

#### jackrae

#4
##### Jun 29, 2013, 09:19 pm
Come to think of it, the gauges might actually be monitoring the current flowing OUT of the S terminal.  Basic fuel level sensors used to be  1-terminal devices using the chassis as a return circuit.  The sense device was a simple variable resistor.  If these gauges are for that design then it is indeed current OUT of the sense terminal that determines gauge reading.

I'd suggest you get an actual sensor, preferably the fuel level sensor, connect it to the gauge and see what actual measurement conditions are.   Note that the sensor chassis body will need connecting to the -ve terminal on the gauge to complete a current loop circuit.

Supply battery connects to + and - terminals on the gauge.