ESP32 + HX711 + 4x 50kg half-bridge load cells - readings barely change under load

[IoTMaker16]

Hi everyone,

I'm building a weighing platform for a shopping cart and I'm using:

* ESP32 Dev Module
* HX711 amplifier
* 4 × 50 kg 3-wire half-bridge load cells (200 kg total)
* Arduino IDE 2.x
* HX711 library

The four load cells are mounted on the four corners of a wooden platform using 3D printed mounts.

Each load cell has three wires: **red, white and black**.

My wiring between the load cells is:

* White from sensor 1 soldered to white from sensor 2
* Black from sensor 2 soldered to black from sensor 3
* White from sensor 3 soldered to white from sensor 4
* Black from sensor 4 soldered to black from sensor 1

The remaining wires go to the HX711:

* Sensor 1 red → E+
* Sensor 2 red → A-
* Sensor 3 red → A+
* Sensor 4 red → E-

HX711 connections:

* VCC → ESP32 3.3V
* GND → ESP32 GND
* DT → GPIO16
* SCK → GPIO17

At first, my readings stayed at zero all the time. After rewiring according to several tutorials, the HX711 now produces values.

For example, with no load I get values around:

-11450 ±100

So the HX711 is definitely reading something.

However, the real problem is that **the readings barely change when I apply weight**.

For example:

* Empty platform: around -11450
* Pressing very hard with my hand: values change only by about 100–200 counts
* Even placing a known weight produces almost no significant change.

The strange part is that the readings are stable, but they simply don't react enough to the applied force.

To isolate the problem, I disconnected everything and tested **only one load cell**.

I connected it like this:

* Red → E+
* Black → E-
* White → A+
* A- left unconnected

When I manually bend or press the load cell, I still only see changes of about 100–200 counts before the value returns close to zero, even while I continue applying force.

At this point I'm wondering whether:

1. My Wheatstone bridge wiring for the four half-bridge sensors is incorrect.
2. The sensors themselves are faulty.
3. I'm mechanically loading the load cells incorrectly.
4. A single 3-wire half-bridge load cell cannot be tested this way with one HX711 input.

Has anyone successfully built a scale using these exact 3-wire half-bridge load cells and an HX711?

Could someone check whether my wiring is correct, or suggest what I should measure next with a multimeter?

Thank you very much for your help.