Kart firmware flasher

Plug the board into USB and flash it from the browser — no PlatformIO, no drivers.

Before you start

Use Chrome, Edge, or another Chromium browser on desktop. Safari and Firefox do not support Web Serial.
Connect the Heltec V4 with a data USB-C cable (some cables are charge-only).
The board uses the ESP32-S3 native USB port — pick the usbmodem / USB Serial device when prompted.

If flashing fails to start, hold BOOT, tap RESET, release BOOT, then click Install again.

Choose firmware

Heltec WiFi LoRa 32 V4 · ESP32-S3

Gateway

WiFi + MQTT + web dashboard. Bridges live timing to the displays over LoRa.

Web Serial unsupported — use Chrome or Edge.

Heltec WiFi LoRa 32 V4 · ESP32-S3

Display

Trackside panel. Receives LoRa, drives the OLED / TM1637, scans BLE zone beacons.

Web Serial unsupported — use Chrome or Edge.

ESP32-C3

BLE zone beacon

Advertise-only beacon marking a track zone (pit / garage / joker). One image for all beacons — set the zone over USB with ZONE:pit after flashing.

Web Serial unsupported — use Chrome or Edge.

After flashing

The board reboots into the new firmware automatically.
Gateway: if no WiFi is stored it opens a setup portal — join the kart-gateway-setup AP (pass kartsetup) and enter WiFi/MQTT.
Display: powers up trackside and hunts for the gateway's LoRa link on its own.
Beacon: set its zone once over the USB serial console (115200 baud) — send ZONE:pit, ZONE:garage, or ZONE:joker. It is stored in flash.

Firmware built from the PlatformIO project in this repo. Board pinout & radio notes: HELTEC_V4_PINOUT.md. This page needs HTTPS (or localhost) for Web Serial — served here behind the Coolify proxy.