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iHeater Link — quick guide

iHeater Link is a connectivity module for the iHeater controller with firmware iheater_revХ_Х_pulse. It is an ESP32-C3 / ESP32-S3 board that:

  • Connects to Wi-Fi and links iHeater to portal.idryer.org.
  • Receives chamber target temperature from the printer through Moonraker (Klipper), Bambu Lab (LAN), or Home Assistant integrations.
  • Converts the target into a pulse signal and forwards it to the iHeater controller over a single GPIO.

iHeater is controlled "over the wire": one signal pin on the ESP feeds the iHeater signal input. Wi-Fi and integrations are Link's job; heating and safety are iHeater's job.

The single-wire link does not constrain where Link is placed. The ESP board can be installed outside the heat chamber. This avoids:

  • chip and peripheral overheating when the chamber runs at 60+ °C;
  • thermal lock-ups of the radio section and Wi-Fi session drops during long heating cycles;
  • accelerated component degradation.

Only the iHeater controller — designed for high-temperature operation — stays inside the chamber. Signal-wire length to the ESP is limited only by reasonable line load (tens of centimetres — no concerns).

Supported boards

Board
ESP32-C3 Super Mini ✅
ESP32-C3 DevKitM-1 ✅
Seeed XIAO ESP32-S3 ✅
Waveshare ESP32-S3-Zero ✅

Any other ESP32-C3 or ESP32-S3 board can be used as long as a free GPIO is available for the signal output. Check the manufacturer's pinout.

Wiring

Never connect or disconnect wires while power is applied.

Power goes to the ESP through USB-C. The ESP, in turn, powers the iHeater controller over the 5 V line. This is the simplest setup. If needed, iHeater power can be sourced separately — Link does not depend on the power scheme.

ESP32-C3 Super Mini to iHeater wiring

Connections (same for all supported boards):

ESP iHeater Purpose
5V 5V controller power
GND GND common ground
GPIO3 signal input pulse setpoint

Board pinouts

ESP32-C3 Super Mini:

ESP32-C3 Super Mini pinout

Waveshare ESP32-S3-Zero:

Waveshare ESP32-S3-Zero pinout

Flashing via the web flasher

The web flasher is hosted at install.idryer.org.

  1. Connect Link to a USB port on the computer.
  2. Open install.idryer.org and select the iHeater Link device.
  3. Select the board variant.
  4. Click Connect and pick the serial port (typically USB JTAG/serial or CH340). If the device is not detected, hold BOOT on the board and briefly press RST.
  5. Click Install. The flasher writes the firmware.
  6. When flashing completes, the Wi-Fi setup wizard opens.

Wi-Fi setup

After flashing, the Improv wizard opens automatically over the serial port.

  1. Enter the SSID and password of your 2.4 GHz network.
  2. Wait for the Connected status. The Link status LED switches to a slow blue "breathing" pattern.

If the wizard does not open, unplug USB and reconnect via Connect without re-flashing.

ESP32 supports 2.4 GHz only. 5 GHz networks will not work.

Pairing with the portal

  1. On the flasher page click Connect and Claim.
  2. The device receives the START_CLAIM command. After a few seconds a PIN is shown on the page. The PIN is valid for ~5 minutes.
  3. Open portal.idryer.org → Add device → enter the PIN.
  4. Once paired, the device appears online in the list.

If the response is CLAIM_ALREADY:DEVICE_…, the device is already paired to this or another account. Remove the device from the portal, then repeat the pairing.

Connecting to iHeater

  1. Power the controller off.
  2. Wire ESP to iHeater per the diagram above: 5V, GND, GPIO3 → iHeater signal input.
  3. Apply power to the ESP via USB. The controller is powered through the 5 V line.

On boot, Link connects to the portal, activates the selected integration, and starts forwarding the chamber target to iHeater.

What you should see

  • LED 1 stays on, LED 3 blinks once per second — Link-to-iHeater communication is established.
  • When the link is lost, all LEDs blink at 1 Hz.
  • All other errors are unrelated to Link and follow the standalone firmware indication.

Diagnostics

The device menu has a DIAGNOSTICS → DIAG LOG entry. When enabled, the serial port outputs a detailed report once per second: Wi-Fi status, MQTT status, active integration, current target, connector errors.

Full diagnostics reference is available in the idryer-core library documentation in the project repository on GitHub.