Fuel Gauge

by jonathan harrocks

A fuel gauge for a 240 x 240 round panel, fed from the diagnostic socket over CAN. The arc fills with the level and carries a pointer round with it. The pointer is a picture named as the arc's Follower: the arc moves it whenever the value moves and turns it so its tip keeps pointing in at the arc, which is the part a plain knob cannot do. The graduations inside are a Scale's own ticks, with the reserve marked as a section of it. The arc is not clickable, because a gauge is not a control: a finger on the glass must not move it. Below fifteen per cent a LOW banner comes up. It reads PID 2F. Not every car reports fuel level over OBD-II; one that does not leaves this at empty, and the device takes a signal of your own for the frame your car puts it in instead.

About this design

Fuel Gauge is an LVGL interface for the ESP32-S3 + GC9A01 1.28" round (GC9A01 / GC9A01A 240 x 240, CST816S touch), with 1 screen and 9 widgets, made for Arduino (C++) on LVGL 9.

Screens

Fuel

Hardware and build

Board: ESP32-S3 + GC9A01 1.28" round
MCU: ESP32-S3
Display: GC9A01 / GC9A01A
Resolution: 240 x 240
Touch: CST816S
Graphics library: GFX Library for Arduino
LVGL: v9
Exports to: Arduino (C++)
Peripherals: CAN bus / OBD-II (car diagnostics)
Libraries: lvgl, GFX Library for Arduino, TWAI driver (bundled with the core)

Notes from the author

Fuel level on a round panel, read from the car over CAN: an arc that fills and a pointer that rides it.

Using it

Open a copy in the designer and it is yours to edit: restyle the screens, move it to another board, and export the Arduino (C++) project. Designing is free, and a copy needs no account. Open the designer.

Every pin of the ESP32-S3 + GC9A01 1.28" round, and the preset this design starts from: ESP32-S3 + GC9A01 1.28" round pinout and LVGL designer.