More testing to be done.
- characterize a single point load cell
- characterize a 5 kg kitchen scale with those four strain gauges on its feet
- acquire correlated measurements with the precision multimeter and HX711 via SPI
- characterize drift over temperature (fridge vs. room temperature)
load cycles: 24h loaded to 100% nominal load, then 24h recovery
temperature cycles: RT (as part of the 24h no-load phase), fridge, RT (~12h each)
seems like now is the time to hook up SPI.
No precision voltage sources will be used this time because HX711 supplies the reference voltage and the measurement scaled to AVDD.
ps. single point cell - temperature drift
The single point cell sense voltage drift looks pretty much the same as that of the 5 kg scale elements one.