I'm using a 120 Ohm strain gauge to read a change in resistance on a simple beam with an axial load. I used the code from this:
https://learn.sparkfun.com/tutorials/force-sensitive-resistor-hookup-guide
As a starting point and ignored the force it gave me but I used the same setup except with 1k ohm resistor. Is there a simple code someone can help me with to measure a simple change in resistance but make it more accurate like to .001 ohms?
I have like zero experience with arduino.
The strain gauges look like this https://wholesaler.alibaba.com/product-detail/metal-foil-strain-gauge-120-ohm_60408351858.html
coogle - wheatstone bridge ic
Post a link to the actual strain gauge you have.
These are normally used in a bridge configuration to balance out temperature and power supply effects, and an amplifier is required to read out the tiny voltage differences. The HX711 module is cheap and easy to use for that purpose.
Google "arduino strain gauge hx711" for lots of tutorials.
A couple of thoughts you might consider:
A strain gauge output is very very low. Typically an instrument amplifier is needed before going into the Arduino A/D.
The strain gauge signal is usually so low that ambient noise becomes an issue. Look in ebay for a HX711 based strain gauge measurement board. Better than the instrument amplifier mentioned in the previous statement.
Bonding of a strain gauge is critical. Look at Omega engineering for some guidance.
Strain gauges change resistance with temperature. Need a plan to deal with this.
Google Strain Gauge tutorial for additional information. I found several with a simple "strain gauge tutorial" search.
Good luck.
Some HX711 info and link to datasheet HERE
Yes, strain guages require high quality amplification to be usable, using a chip designed for the purpose
(most standard opamps are not going to work well due to the CMRR and PSRR requirements of microvolt
DC signals).
I used the LT1215 and the schematic on page-1 with very good results. The gain I measured was actually greater than the 20 shown in the graph. It's been quite a while since I breadboarded that circuit but I seem to recall the gain was close to 50. But then , my age being what it is , I could be mistaken. In any case, this is an excellent op amp and that amplifier circuit works very well.
It sounds like you could use a tutorial on the Wheatstone Bridge
The simplest solution, change R2 to 4.7k, add 10 Meg resistor parallel to C1.
Very good circuit , can detect shorted PCB trace - drop voltage between two (A.B)points of the trace , A B =1"