I’m a high school technology / engineering teacher looking for help on a classroom project. I’m hoping people with more electronics knowledge can help guide me in the correct direction.
I’m looking to use an S-style load cell for a homemade material strength tester. I would like to graph the output using Vernier’s Graphical Analysis Pro software. The software requires a 0-5V or 0-10V input signal.
My plan was to use an Arduino minima with a sparkfun load cell amplifier board. I would use the DAC on the minima to output the desired voltage to the vernier software. We do not need highly accurate measurements.
Does this sound reasonable? I have seen some load cell amplifier circuits online that output the desired voltage range but I have had back luck with imported boards in the past. I would like this system to be reliable or classroom use.
Most S-type load cells output a very small signal in the millivolt range.
You need a very precise amplifier. The DAC of the Arduino Minima only outputs 0-3.3V, not 0-5V. So, you have to scale it to 0-5V or 0-10V using an OP-AMP. I think it will be simpler if you use a Load cell, an HX711/ADS1232, an Arduino+External DAC and then connect the DAC output to the Vernier. Here are some more suggestion related to interfacing S-type load cells with the Arduino. S Type Load Cell with Arduino and HX711 - Sensors - Arduino Forum
Do you want a project or a solution? In the instrumentation biz, that’s called a transmitter. An industrial controller will do this effortlessly. They’re often in a DIN rail mount package for use in automation cabinets. Below are some reputable ones but I’m sure some cheaper ones are out there for the finding.
Edit: They’re also called conditioners or just amplifiers.
Some load cells have an amplifier built in using a device like this:
