I am trying to make a low power device (based of RSL10 bluetooth SoC) that would sample a strain gauge @1kHz and transmit the measurements. The current drawn by the running SoC is about 1.5mA, while the current for the gauge excitation is about 3mA (1kOhm @ 3VDC) assembled in a 4-gauge Wheatstone bridge.
I wish to keep the gauge current in sub-mA current range, but they seem to not make stain gauges of higher resistance. I think the ones I have are 350Ohm each with some additional resistors to make it to a 1kOhm.
- I could add more series resistors outside the bridge, but I think this will make the assemble less sensitive to changes.
- Another option is using a buck converter to step up the excitation voltage, but this procedure would not help decreasing the power consumption.
Does anyone have an idea on how to implement the stain gauge assembly that would not require such (relatively) high current?