any information on connect uC with straingauge

[tobb]

www.linear.com/pdf/an43.pdf

I want to built weight measurment control with Micro controller which have 10bit ADC on it. But my problem is i have no idea how to connect straingauge or loadcell to ADC off micro controller port. the straingauge that i have it give very small value different. ie output A give 3.05 volt and Output B give 3.052 V when 15 Kg load. How could i measure this different voltage between A & B with uC.... Thank for your help

 

[jzo777n]

You connect an instrumentation amplifier between output A and B that measure the difference in the bridge and amplify it.
A suitably is for ex. AD622 from Analog Devices.
Other manufactures of Inst. Amp are Texas instrument, Linear technology, Maxim, ST and more...
Linear technology has a good app note, see https://www.linear.com/pdf/an43.pdf

and more about straingauge https://www.vishay.com/company/brands/measurements-group/guide/index.htm

 

[techie]

Since you are using a 10-bit convertor, I dont suppose you need too much of a resolution. A simple low drift opamp like OP07 can do the job. (Dont use general OPamps like 741, they have a large drift). For better performance, you might have to use 2 or 3 stage amplification.