Torque Sensor: Reading Negative Voltages

Hey guys ! I’m having trouble getting readings from my torque sensor. I have never used a device that has both (+) and (-) signals. I was thinking of putting both signals into the analog pins on the arduino, but I was hesitant because I was afraid I would fry it. Has anyone here used a sensor that has a (+) and (-) output signal ? I have also done some research on op-amps in order to amplify the signal as well because the sensor has a Rated Output of 2mV/V nom. I have attached a spec sheet for the part that I am using.

If anyone has any experience with reading (+) and (-) signals on arduino and using op-amps I would greatly appreciate the help.

Thank you !

Torque Sensor (tff350).pdf (234 KB)

You need an instrumentation amplifier to interface with the Arduino.

The INA12x series might be suitable, or you could consider the HX711 load cell amplifier (it is slow).

It says it uses strain guage technology, so it's going to be a Wheatstone bridge. This creates a differential output voltage and cannot just be hooked up to the Arduino ADC input.

The strain guages in the device form a voltage divider, so the output voltage it proportional to the excitation voltage. That's how to interpret the 2 mV / V rated output spec. If you excite it with 10V, the output at the maximum rated torque will be 20 mV. If you excite it with 5V, the full scale output will be 10 mV.

The load cell amplifier will work perfectly. A torque sensor is basically just a rotational load cell after all. The only thing you must be wary of is that the excitation voltage must be as low noise as possible. You should have a separate regulator that only powers the torque sensor and is the reference for the ADC. Do not power it off of the Arduino's regulators.

Thank you JRemington and Jiggy-Ninja ! This was the missing puzzle piece :D