We took a $20 digital scale from Target and hooked it up to an amplifier and a microcontroller. This video outlines taking apart the scale, wiring it to the amplifier, and the code, as well as an overview of the concepts behind strain gauges and Wheatstone bridges. There’s a demo of two live scale apps written in Python near the end of the video.
For the source code or more information about our microcontroller kits, go to https://www.nerdkits.com/videos/weighscale/