| Ö1 |
Load cell wire polarity. The Gefran TU datasheet only states which wires are excitation (white/green) and signal (red/yellow or black), not which is + and −. |
Open. In firmware the raw counts are assumed to rise with tension and LOAD_CELL_INVERT_SIGN in include/load_cell_config.h (default false) corrects the wire polarity. The screen shows compression positive and tension negative (LOAD_CELL_COMPRESSION_POSITIVE). |
Check against the cell's calibration certificate (S/N 26390078), then pull the cell in tension and see a negative reading (push it and see a positive one) |
| Ö4 |
Supply voltage to the Load cell click (3.3 V or 5 V) and the resulting DOUT logic level towards the ESP32-P4. |
Open. VSUP is always fed from +5V (5 V wire required); DVDD, and therefore the DOUT level, is selected by the SMD jumper printed "VCC SEL". Decision: bridge on the left pair ("3V3") → 3.3 V logic. MIKROE product page states left is the default. |
Check the jumper on the actual board and measure DOUT high level (≈ 3.3 V) |
| Ö5 |
ESP32-P4 board header P6 pin numbering: pins 1/3 = 5V, 2/18 = 3V3, unlike the Raspberry Pi convention (pin 1 = 3V3). |
Open. Waveshare schematic and Waveshare pinout diagram agree. The header is only marked "1", "2" and "GPIO" on the board. |
Measure 5 V / 3.3 V against GND on the actual board before connecting wires |
| Ö6 |
Connection of the 10.1-DSI-TOUCH-A display. |
Open. Waveshare wiki: the display needs 5 V (4.75–5.30 V), 0.8 A typ., via its own 2-pin power cable, not via the DSI cable. Decision: power cable red → P6.1 "5V" (P6.1 and P6.5 are not adjacent, so separate leads), black → P6.5 "GND". Still unknown: display-side DSI connector/cable type for the 15-pin J1, printed labels on the display power connector, and the board's own 5 V consumption (supply sizing). |
Fit the cables, measure display current at 5 V, display shows image and touch works |
| Ö7 |
Load cell cable screen termination. Gefran: earth at the instrument end only. The Load cell click has no dedicated screen terminal. |
Open. Proposal: screen (GNYE) in TB1.1 together with EXC− (GND). |
Decision by user, then check noise on the reading |
| Ö9 |
Reference designation class codes -BW1 (load cell), -TF1 (signal converter), -PH1 (display), -WG1…4 (cables) are a proposal; only -KE1 is given in 01-overview. |
Open |
Check against the tables in SS-EN IEC 81346-2:2019 |
| Ö10 |
Touch controller type and driver. Docs say GT9271, the firmware uses the GT911 driver from Flip-HMI (identical code). |
Open. Touch works on the board (confirmed by the user 2026-10-16); the controller type has not been recorded yet. The driver probes I²C 0x5D then 0x14 and prints TouchPad_ID:0x..,0x..,0x.. at start-up; the bytes are ASCII "911" for a GT911 and "927" for a GT9271. |
Read the line in the serial monitor and confirm that touch works on the buttons |
| Ö11 |
Backlight control. The firmware runs both the I²C bridge sequence on device 0x45 (registers 0x95/0x96) and PWM on GPIO26, as in Flip-HMI; the brightness setting writes the value to I²C 0x45 registers 0x86 (Waveshare wiki) and 0x96 and to the PWM, and the brightness then follows the slider (confirmed on the board 2026-10-14); it is not known which of them is needed. GPIO26 (backlight PWM) and GPIO27 (LCD reset) are listed as USB pins on the board in the electrical drawing, section 5.2; the numbers come from the Waveshare LCD-X example code. See 05 – Software, section 7.2. |
Open |
Brightness control works. To close: write only one of 0x86 / 0x96 at a time in src/backlight.cpp, and remove display_cfg_backlight(true) and the bridge writes in display_cfg_prepare() one at a time, and note what is really needed |
| Ö12 |
Scale of the reading. Until a calibration is stored, the force uses the ideal estimate 2^23 × 0.512 / 200 kg ≈ 21 475 counts/kg. |
Open. The CALIBRATE function on the screen sets the real value from a known weight. |
Calibrate with a known weight and compare with the estimate; check a second weight afterwards |