Measuring temprerature sensor resistance

Other Hardware Sensors
1

Hi guys!
I'm working on a project, a dashboard for an old tractor that I'm restoring.
I want to create its dashboard with fuel, coolant temp, oil pressure, etc

My problem is the following:
The temperature sensor port on the engine block only accepts a sensor that has a 22mm thread.
The sensor works, but it has only one wire, "the second" wire is essentially the body of the tractor.
I was not able to find a temp sensor that has the same thread and two wires at the same time

I have a second case of this type of sensor, the fuel level sensor, it also only has one wire.

My question is: How can I measure these two sensors at the same time, without them disturbing each other? (Arduino is going to send 5V across the body and read the resistance)
Considering that the body of the tractor is directly connected to the minus of the battery, is there any interference or potential for trouble?
Can this work without risking damage to the Arduino?

Worst case scenario, I'll search for a skilled guy who could make me some thread adapters for the proven sensors that work with Arduino

Thank you in advance!

2

Implement signal filtering techniques to reduce any noise or interference.

3

No

Can this work without risking damage to the Arduino?

Yes

How can I measure these two sensors at the same time, without them disturbing each other?

The more important question is how do you actually read these sensors at all and convert it to a voltage that the Arduino can use

5

I can measure the sensor when I use the Arduino as an ohm meter.
The resistance at 10 degrees Celsius is about 2K and drops as the temperature increases up to about 500ohm or less when it reaches working temperature (90 degrees).
I yet have to make some more measurements to match up the resistance values to actual temp (I'm using a second temperature sensor for calibration purposes).

Essentially I will send 5V to the body of the tractor (I'll try to attach a wire to the body of the sensor) from the Arduino and read it back from the output of the sensor, I see no other way.

Hence my question, would this work if the thing I'm sending 5V to is also the minus of the big tractor battery?

I have only measured the sensor take off the tractor because I was afraid of burning the arduino

6

No, you connect the arduino GND to the body of the tractor not the 5V.
The 5V goes to the voltage divider you use in your ohmmeter set-up

7

Any more questions?

8

Consider that a win, you only have to run a single wire to your Arduino.

Connect it through a resistor of suitable value (depending on the value of your thermistor - which this temperature sensor most likely is), and read the mid point of the divider with your analog input.

Likewise for the fuel sensor.

Some input protection and noise filtering may be in order indeed, as suggested above.

9

Perhaps something like this adapter?

10

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