garage-display

The time, the date, the outdoor weather and the garage temperature on an Elecrow 2.8" ESP32 display, updated over WiFi.

┌────────────────────────────────┐
│        12:45 PM                │
│   Saturday 27 September 2026   │
├───────────────┬────────────────┤
│   OUTSIDE     │    GARAGE      │
│    58.2       │     64.7       │
│   71% RH      │    48% RH      │
└────────────────────────────────┘

• Outside: Open-Meteo, every 15 minutes. Also supplies sunrise and sunset.
• Garage: an AHT10/AHT20 on the I2C connector (SDA 22, SCL 21), every 10 s, also published to MQTT. With no sensor fitted, the display reads the same MQTT topics instead.
• Time: SNTP, Pacific time. The board has no RTC, so it shows --:-- until the network has answered.
• A reading that has stopped updating is dimmed.
• White text by day, red at night. The backlight is 80% by day and 5% at night.
• Hold a finger on the screen for a second to switch between °F and °C.

Hardware

Elecrow "2.8inch ESP32 Solo Miner LCD Display": ESP32-WROOM-32-N4 (4 MB flash, no PSRAM), ILI9341 320x240 on SPI, XPT2046 resistive touch, CH340C USB serial. Every pin is in src/board_pins.h; the reasoning is in docs/superpowers/specs/2026-09-27-garage-display-design.md. The full hardware reference, with vendor-documentation errors, is docs/HARDWARE.md.

Build and flash

1. cp secrets.ini.example secrets.ini and fill it in.
2. The build fetches esp32-ota-kit v1.0.0 from GitHub; no account is needed.
3. First time, over USB: pio run -e garage_display -t upload
4. Serial log: pio device monitor, or ~/.platformio/penv/bin/python tools/capture_serial.py 30.
5. Host tests: pio test -e native.

Updating over WiFi

1. Bump custom_fw_version in platformio.ini.
2. pio run -e garage_display_ota -t upload

The display shows the progress and reboots into the new version. If the new version crashes before it has been up for a while, the bootloader goes back to the previous one by itself. This was verified on this board at 1.0.1.

• Push hangs at "Waiting for device": the Mac firewall is blocking PlatformIO's Python. The device connects back to the computer, so allow incoming connections for it.
• The name does not resolve: check ping garage-display.local.
• Security: espota pushes over UDP+TCP on the LAN, and the OTA password is checked by a challenge-response, not sent. But the firmware image itself crosses the network unencrypted, and it contains the WiFi password, the OTA password and the broker address in plain text - anyone sniffing a push can read them. Keep the display on a trusted network.
• Power-cycling mid-update: cutting power within about 40 s of a push (before the new image is confirmed) reverts to the previous version.
• "esp_core_dump_flash: Core dump data check failed" at boot: harmless - the core-dump partition is just empty.

Factory firmware

The board's factory image was saved to backup/factory-miner.bin (not in git) before the first flash; despite the product's "miner" name, that image is Elecrow's lv_micropython v1.19.1 build with their DHT20/LED MicroPython demo (see docs/HARDWARE.md). To restore it:

~/.platformio/penv/bin/esptool --port /dev/cu.wchusbserial2120 write-flash 0 backup/factory-miner.bin

Layout

Path	Contents
src/main.cpp	Startup order and the loop
src/ui.*	The text view
src/board_pins.h, display_driver.*, touch.*, backlight.*	This board
src/source_aht10.*, source_mqtt.*, source_weather.*	Where readings come from
src/net.*, wallclock.*, brightness.*, update_overlay.*	WiFi, time, backlight policy, OTA progress
src/fonts/	Generated digit fonts, with the recipe
lib/	Pure, host-tested logic
test/	Unity tests for lib/
tools/capture_serial.py	Resets the board and prints its log

Much of src/ and lib/ comes from the CrowPanel 7" temperature display (Crowpanel-Advance-7.0-HMI-Display, commit feee6c1).

Authorship

Author: Mark Castelluccio markacastelluccio@gmail.com

Written with assistance from Claude Code (Anthropic).

MIT licence; see LICENSE.