Hello
Any thoughts to interface with torque sensor which output is highspeed differential signal (few millivolts aprox 20khz)?
Or atleast that is the way I figured out how to use this kind of sensor, inside electric bicycle?
There was samekind thread
https://www.eevblog.com/forum/metrology/reading-a-magneto-elastic-torque-sensor-with-high-resolution/ in few years ago - but the post seem dead, so I started new one.
But like in the old thead the sensor has two identical coils, each with 15ohm resistance - and one end connected together.
Inside the coils is foil which has cut outs, mirrored to eachother. My gues is that when the foil is twisted by torque the cut out somehow move to increase one coil impedance and decrease the other.
The problem is that even I apply quite a lot torque, I can only measure few % variation in my test circuit.
Example without torque I have 300mV difference, with all what I can twist with couple of big wrenches I get 294mV
The frequency has to be high so that the skin effect causes the foil only to affect the measurements.
Can I just put instrumenal amplier? with 1000X gain to get few volts output?
And another question, can I supply the coil with sinusoidal DC - or do I have to use AC. DC just would make easier for power supply setup