Note that all yellow parts in this image are to be printed with 95-98A Shore hardness TPU, all others PLA at no less than 80% rectilinear infill, and no less than 5 walls and 5 top and bottom layers
Note that nuts are not mentioned, but should be included as 1:1 with each respective bolt
A search yielding load cell kits, get 1 HX711 per load cell, or an additional 6 pack of HX711 breakout boards note that most kits only give you a single HX711 per 4 load cell modules.
Now before you begin, please refer to this guide on which traces to cut and resolder to enable 80hz update rate on the HX711
A much simpler version of the above can be seen in this image (lift pin 15 and connect it to pin 16)
| HX711 board | HX711 pin | ESP32 pin | Notes |
|---|---|---|---|
| All modules | VCC | 3 V3 | 3.3 V supply (do not use 5 V) |
| GND | GND | Common ground with ESP32 & load cells | |
| SCK | GPIO 4 | Shared clock line for all four HX711s | |
| Load-cell 0 | DOUT | GPIO 32 | Independent data line |
| Load-cell 1 | DOUT | GPIO 12 | Independent data line |
| Load-cell 2 | DOUT | GPIO 13 | Independent data line |
| Load-cell 3 | DOUT | GPIO 15 | Independent data line |
Load-cell wiring reminder (typical 3-wire): • White (Excitation +) → HX711 E+ • Black (Excitation –) → HX711 E- • Red (Signal) → HX711 A+ (A pair of 1k resistors are tied to E+ and E1, and their shared connection is used as a reference signal against A-) • Verify signal wire by checking resistance between all wire pairs • Signal will be 1kOhm between each exitation wire, and exitation +- will be 2kOhm
All four HX711 breakout boards share the same clock (SCK ↔ GPIO 4) while each has its own DOUT pin, allowing polling independently at full speed.
interface.py frontend, click on pads to toggle index selection, and apply -100 pressure for 2 seconds to assign
