Parts

Parts#

Below is the list of parts used in the project. You will also need a solderless protoboard and wires.

Code samples are written for an ESP32. The particular model I’m using is a Huzzah32, but other versions will work, too.

For reference, here is the pinout:

I’m using a load cell similar to this one. Choose lower or higher weight rating, depending on your application.

For convenience I’m using a FeatherWing OLED that stacks directly on top of the Huzzah32, with no wiring required.

The board also has three buttons, connected to pins as follows: A=15, B=32, C=14.

The HX711 is an ADC specialized to reading load cells. It gives better accuracy than the ADC built into the ESP32

The picture below shows the assembled scale with the display mounted on top of the Huzzah32.

I used laser cut acrylic for the load cell.

The load cell is “sandwiched” between the base and the tray, with a spacer on either side to permit it to allow it to move.

Now we are ready to wire up the circuits. Open $IOT_PROJECTS/balance/02_circuit.ipynb.