Bench Supply Meter

by jonathan harrocks

A bench supply with no display, given one that reads better than most. An INA219 sits across the output and reports voltage, current and power over I2C. It is drawn as the front of a bench instrument: windows in a panel, and digits over their own unlit segments. The second screen sets the current you want warning about, with + and - keys - a variable the spinbox writes and an automation reads. Both screens are laid out in the same windows of one picture, which is half the flash of a picture each. Nothing is switched: an INA219 measures, it does not interrupt. The banner tells you, and what you do about it is yours. Exports as ESPHome, so there is no compiler to install - one command flashes it.

About this design

Bench Supply Meter is an LVGL interface for the ESP32 + ILI9341 2.8" SPI (ILI9341 240 x 320, XPT2046 touch), with 2 screens and 34 widgets, made for ESPHome on LVGL 9.

Screens

Live
Limits

Hardware and build

Board: ESP32 + ILI9341 2.8" SPI
MCU: ESP32 (WROOM / WROVER)
Display: ILI9341
Resolution: 240 x 320
Touch: XPT2046
Graphics library: TFT_eSPI
LVGL: v9
Exports to: ESPHome
Peripherals: INA219 (current)
Libraries: lvgl, TFT_eSPI, Adafruit INA219

Notes from the author

Volts, amps and watts from an INA219, with a current limit you set on the panel.

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 ESPHome project. Designing is free, and a copy needs no account. Open the designer.