Compacting Load Cell Electronics

After being pleasantly surprised by the performance of a low cost strain gauge load cell built from a kit sold on Amazon, I decided it was worth the effort of making a more compact version of the circuit. Small enough so it can be installed on the Y-axis carriage of a Geeetech A10 chassis alongside the strain gauges being read.

First of all, the prototyping breadboard had to go. It is far too large and bulky and serves no purpose once the wiring scheme has been confirmed and would actually be a source of failure if jump wires fall out. I don’t need the Arduino Nano mounted on that breadboard, either. It has two full rows of pins which I won’t need. I could spend the time to desolder those pins, but it is much easier to pull a new unit out of its box as they come without the pins. I can solder wires directly to the vias matching what I need for power, ground, data, and clock.

I did, however, need to desolder the four pins on the HX711 interface board, they are no longer necessary. Once they were removed, I could put the Arduino Nano and the HX711 board side by side and the four short wires between them.

Finally, a small 3D-printed bracket whose only purpose was to hold the two PCBs together, removing any strain from the four wires connecting the two PCBs. The idea is that I may want to explore different ways to mount this assembly, but I always need to have the two boards next to each other. Thus the motivation for a separate bracket for actual mounting to Y-axis carriage.

The Y-axis carriage clip didn’t work as well as I had hoped, but for the moment I’m not going to worry about redoing it. A little tape is enough for me to move on to the next step: feeding its data output to a computer system.

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