02 – Component list¶
| # | Function | Component | Manufacturer | Qty |
|---|---|---|---|---|
| 1 | Display | 10.1-DSI-TOUCH-A | Waveshare | 1 |
| 2 | Control board | ESP32-P4-WIFI6-POE-ETH | Waveshare | 1 |
| 3 | Signal converter | Load cell click (HX711) | MIKROE | 1 |
| 4 | Load cell | TU-K2C, part no. 2130X000X00, S/N 26390078 | Gefran | 1 |
1. Display – Waveshare 10.1-DSI-TOUCH-A¶
- 10.1" IPS panel with capacitive touch
- Interface: MIPI-DSI (video) and I²C (touch)
- Connects to the control board's DSI connector J1 (15-pin) for video and touch
- Power: separate 5 V, 0.8 A typ. (4.75–5.30 V) via its own 2-pin power cable (Waveshare wiki)
- Touch controller GT9271; backlight set over I²C (device 0x45, register 0x86)
2. Control board – Waveshare ESP32-P4-WIFI6-POE-ETH¶
- Main processor: Espressif ESP32-P4 (RISC-V, dual-core)
- Wireless: Wi-Fi 6 / Bluetooth via a separate ESP32-C6
- Ethernet with PoE power
- MIPI-DSI connector for the display
- GPIO header for connecting the Load cell click
- Reference:
ESP32-P4-WIFI6-POE-ETH-Schematic.pdf,esp32-p4_datasheet_en.pdf
3. Signal converter – MIKROE Load cell click¶
- ADC: Avia HX711, 24-bit, designed for weigh scales
- Two differential inputs: channel A (gain 128 or 64), channel B (gain 32)
- Input range channel A, gain 128: ±20 mV (at 5 V AVDD)
- Output data rate 10 or 80 SPS (selected with the RATE pin)
- Supply 2.6–5.5 V; on-chip regulator for bridge excitation
- Digital interface: two wires, PD_SCK (clock) and DOUT (data)
- mikroBUS pins used:
| mikroBUS | Signal | Function |
|---|---|---|
| PWM | CLK | HX711 PD_SCK (clock in) |
| INT | DO | HX711 DOUT (data out) |
| CS | RTE | Output data rate select (10/80 SPS) |
| 3V3 / 5V | – | Supply |
| GND | – | Ground |
- Reference:
HX711 datasheet.pdf,load-cell-click-schematic-v100.pdf, MIKROE product page (MIKROE-3168)
4. Load cell – Gefran TU-K2C¶
| Parameter | Value |
|---|---|
| Type | Compact tension/compression load cell |
| Measuring range (K2C) | 0–200 kg |
| Accuracy class | 0.2 % |
| Nominal output | 2 mV/V |
| Input / output resistance | 350 Ω / 350 Ω |
| Nominal supply | 10 V (max 15 V) |
| Compensated temperature range | −10…+50 °C |
| Permitted static load | 130 % of Ln |
| Rupture load | > 300 % of Ln |
| Protection | IP67, stainless steel |
| Mechanical connection | M12 thread, 4 × M5 holes |
| Cable | Screened, 4 × 0.25 mm², 5 m |
Wire colours:
| Colour | Function |
|---|---|
| White | Excitation |
| Green | Excitation |
| Red | Signal |
| Yellow or black | Signal |
| Yellow-green | Shield (isolated from the body, ground at the instrument end) |
Polarity (which excitation wire is + and which signal wire is +) must be verified against the cell's calibration certificate before connecting.
Reference: Gefran_TU_Datasheet.pdf
Compatibility HX711 ↔ load cell¶
The load cell is specified for 10 V excitation but works with the lower excitation of the Load cell click (approx. 4–5 V). The output scales linearly with the supply:
- At approx. 4.3 V excitation: 2 mV/V × 4.3 V ≈ 8.6 mV at 200 kg
- Fits well within the ±20 mV range of HX711 channel A (gain 128)
- Calibration is done against a known weight, so the exact excitation voltage does not need to be known