Controlling OLD car cluster gauges with arduino.

Projects General Guidance
1

Hi, I just got an Arduino and started working on a project, my goal is to replace the sensors on my car and display a more precise value on the gauges (Analog), I got the reading part, I used the stock temperature sensor (ECU SIgnal), then Maple to get the equation from the tables on the service manual.

The oil pressure sensor that I got outputs a 5V signal and its linear, I'm using a Nokia 5110 LCD and everything works great but I have no Idea on how to move/control the gauges, I was hoping to drive these as an Ammeter, using PWM outputs and a generic transistor, upon inspection these are not like that, the Oil pressure is some sort of filament with a coil, the manuals says its a Bi-Metal Type, it has 2 inputs, B+ and a grounded sensor that is not a resistor type, it just switches on/off according to the pressure, the Temperature gauge is a Coil Type, it has 3 inputs B+, Ground and a thermistor.

Specs (Ohms):
Coolant temp gauge resistance: Between A - B = 51, A-C = 139, B - C = 190.

Oil pressure gauge resistance: 42.

I know that arduino can do 0-5V or PWM, looking at the gauges, oil pressure expects an on/off signal from a 12V, the Temperature gauge a variable resistance, any recommendations?

Thanks.

meterdiag.png
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2

Use transistors, I.e either normal NPN bipolar or FETs to drive your dials,

Look at tread called arduino basic connections there is a example called Light a lamp. Which shows how to do this using a small transistor, a 2n2222 your dials may need higher current do you may need to use a larger transistor, but the concept is the same

3

Before opening the cluster I was thinking of something like this:

http://www.w1xbs.com/?p=430