Voltage measurement with strain gauge and arduino uno

Other Hardware General Electronics
1

Hello! I'm kind of new to the electrical side of things and I am working on a task to measure changes in voltage from a strain gauge attached to a pressure vessel.

the configuration I will use is half-bridge wheatstone, as in the picture

Resistor_120_Ohm_20240603_171549_0000
Resistor_120_Ohm_20240603_171549_00001414×2000 437 KB

my question is:

  1. Is the circuit picture I provided correct?
  2. How do I connect the output to the Arduino because there are 2 cables there?
  3. How to amplify the change in resistance of the strain gauge because the change in the surface of the pressure vessel will be very small?

sorry if there something wrong in my project, please give me suggestions thankyou:)

2

Your schematic looks correct, as far as it goes.

Strain gauges are generally used in conjunction with an Instrumentation Amplifier.

You can make your own from a quad op-amp, but there are dedicated Instrumentation Amplifier ICs.

An Instrumentation Amplifier solves your problem in point 2 above. The two outputs of the bridge get combined, and there is a single output to connect to an analogue input on the Arduino.

1 Like
3

My answers:

  1. Somewhat okay, hard to read. Better provide a circuit diagram.
  2. Arduinos can have differential ADC - see the data sheets.
  3. Use some opamp, better some bridge IC with integrated ADC.

Also see the Related Topics below.

1 Like
4

What you want is one of these

1 Like
5

I was also going to mention the HX711, but jim-p beat me to it.
There is a tutorial about using it at:
https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide#hardware-hookup-

1 Like
6

Thanks, I will try HX711 as @jim-p and @JohnLincoln mentioned

1 Like
7

Thanks Guys I did it, I did an eksperimental using 1 straingauge on a metal ruler and the data show at 50 mV, when I bend the ruler down it change to 60 mV and 40 mV when bended up. Is there any way I can reduce the noise? because sometimes the data jumping to 55 mV at idle position.

8

Use read_average(times) with times = 50

9

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.