Mellow Fly - vvuk/eddy-ng GitHub Wiki

Mellow toolboards such as the SHT36 are supported by eddy-ng. These "Pro" versions have a built-in LDC1612 sensor and connect via USB or CAN.

Preface

This guide assumes that you already have your CANBus network working and your toolboard connected via CAN.

If you do not yet have CANBus set up, please refer to the CANBus setup guide:
👉 Esoterical CANBus Getting Started Guide

This documentation only covers eddy-ng specific setup and configuration for the Mellow Fly SHT36 board.

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Hardware Setup

• Mount the Mellow Fly sensor board approximately 5–6mm above the nozzle.
• Ensure proper cable routing to minimize electrical noise on signal and sensor lines.

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Software Setup

Once your toolboard is connected via CAN and flashed with appropriate firmware, configure the following components in your printer.cfg:

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MCU Definition

Define your Mellow Fly board as a CAN-connected MCU:

[mcu SHT36]
canbus_uuid: <your_fly_board_can_uuid>

Replace <your_fly_board_can_uuid> with the UUID you retrieved using canbus_query.py.

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Temperature Sensor Setup

Set up the LDC1612 onboard thermistor like this:

[temperature_sensor fly_eddy]
sensor_type: Generic 3950
sensor_pin: SHT36:gpio28

• Pin GPIO28 is for the thermistor that is located on the LDC itself.
• Adjust thermistor settings if a different sensor is connected.

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Eddy Current Probe Setup

Configure the eddy current sensor:

[probe_eddy_ng fly_eddy]
sensor_type: mellow_fly
i2c_address: 43
i2c_mcu: SHT36
i2c_bus: i2c1e
x_offset: 0
y_offset: 27.8
i2c_speed: 4000000
tap_target_z: -0.350

Explanation:

• sensor_type: mellow_fly — Use the preset for the Fly SHT36 board.
• i2c_address: 43 — Typical address for the onboard LDC1612.
• i2c_mcu: SHT36 — Reference the MCU section defined above.
• i2c_bus: i2c1e — The specific I2C bus used by the sensor.
• i2c_speed: 4000000 — Set to 4MHz I2C bus speed for best performance.
• tap_target_z: -0.350 — Target Z offset used for TAP emulation (fine-tuning probing).

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Notes

• The Mellow Fly sensor usually works reliably with a Drive Current setting of 15, covering a probe range of approximately 0–15mm.
• If your minimum valid probe height is unusually high, double-check the sensor mounting distance. The sensor should be positioned around 5–6mm above the nozzle.
• Ensure your CANBus network is properly terminated with 120Ω resistors at both ends for reliable operation. You should measure 60Ω across H&L when the printer is off and everything is connected.

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