Hi,
I recently picked up a loadcell from SparkFun; it has a 50kg capacity. (specifications here: https://www.sparkfun.com/datasheets/Sensors/loadsensor.pdf). When it arrived, I noticed that it only had 3 wires: red, white, and black. I believe it might be in a half whetstone bridge configuration. Not what I expected, but I'll have to make due for now.
In any case, I connected the White wire to a 6.54VDC power source, the Black wire to GND, and the Red wire is what I was intending to connect to the V+ and V- of my LM358N instrumentation amplifier (a diagram of which can be seen here).
I noticed that if I connect the + of my voltmeter to the Red wire, I get a reading of 3.269VDC. Applying pressure to the load cell with a pair of pliers will result in a 2mV drop, so 3.267VDC. Upon releasing the pressure, it will return to the b3.269VDC baseline.
A few questions:
Should I not just be seeing a value of between 0mv and 2mV coming out of the load cell?
(related to #1) If the 3.269VDC output is not correct, how do I correct this behavior to attain the expected result range?
How should I connect this half-whetstone bridge load cell to my LM358N? (a diagram or a detailed explanation would be very helpful!)
Thanks all, I am new to the whole circuitry thing, but I am a quick learner.
I recently picked up a loadcell from SparkFun; it has a 50kg capacity. (specifications here: https://www.sparkfun.com/datasheets/Sensors/loadsensor.pdf). When it arrived, I noticed that it only had 3 wires: red, white, and black. I believe it might be in a half whetstone bridge configuration. Not what I expected, but I'll have to make due for now.
In any case, I connected the White wire to a 6.54VDC power source, the Black wire to GND, and the Red wire is what I was intending to connect to the V+ and V- of my LM358N instrumentation amplifier (a diagram of which can be seen here).
I noticed that if I connect the + of my voltmeter to the Red wire, I get a reading of 3.269VDC. Applying pressure to the load cell with a pair of pliers will result in a 2mV drop, so 3.267VDC. Upon releasing the pressure, it will return to the b3.269VDC baseline.
A few questions:
Should I not just be seeing a value of between 0mv and 2mV coming out of the load cell?
(related to #1) If the 3.269VDC output is not correct, how do I correct this behavior to attain the expected result range?
How should I connect this half-whetstone bridge load cell to my LM358N? (a diagram or a detailed explanation would be very helpful!)
Thanks all, I am new to the whole circuitry thing, but I am a quick learner.