General information regarding the Fly-SHT36 Max V3 Toolboard


This page covers any general information for the Fly-SHT36 Max V3 toolboard.
It is currently available through AliExpress.
This toolboard is only supported from firmware version 3.5.1 and above.
The Fly-SHT36 Max V3 is compatible with both Duet 3 boards and STM32H723, STM32H743 and STM32F4 boards with spican modules running 3.5.1 and above.

There are 3 versions of the Fly-SHT36 Max V3. Only the Max supports RRF.

Fly-SHT36 Max V3 Versions
Fly-SHT36 Max V3 Versions

Hardware Overview

Processor Raspberry Pi RP2040
Processor Features Dual ARM Cortex-M0+ @ 133MHz, 264kB on-chip SRAM
Networking/Comms CAN-FD, USB Serial Port (and CAN and RS232 for klipper)
On-board stepper driver 1 x TMC-2209
Stepper driver features Up to 1.6A peak current, microstep interpolation from any setting to x256, stall detection, stealthChop2
High current outputs 1 x 10A, VIN voltage only
Thermistor/PT1000 inputs 1 x input, optimised for 100k thermistors and PT1000 sensors, 1 x onboard NTC3950
PT100 Support for 2-wire, 3-wire and 4-wire PT100 temperature sensors
Medium current outputs 2 x 2-pin fan outputs, voltage selectable between VIN, 12V and 5V. 1A max per output
Inputs/Outputs 3 x on-board I/O connectors for endstop, switches, filament monitor, Z probe. 1 x servo output.
Accelerometer Integrated LIS3DH accelerometer
Scanning Probe LDC1612 with scanning probe support

Fan Mosfets

The Fly-SHT36 Max V3 has a unique feature in that the fan mosfet is replaceable. Each mosfet (VS3622e) controls two of the fan outputs. The orientation that the fan mostfet is plugged into the board doesn’t matter.

Fly-SHT36 Max V3 Fan Mosfet
Fly-SHT36 Max V3 Fan Mosfet

Fan Voltage

The fan voltage can be set using jumpers to either 5v, 12v and Vin.

Fly-SHT36 Max V3 Fan Voltage Jumpers
Fly-SHT36 Max V3 Fan Voltage Jumpers Diode

If using with a simple switch, install a jumper to bypass the diode (marked diode BP on the pinout). Don’t install the jumper if using any electronic probes such as an inductive or optical sensor.

CAN Termination

If using a single toolboard, make sure the CAN jumper is installed, as indicated on the pinout.
If using multiple toolboards, only the last toolboard should have a CAN jumper installed.

PT1000 Support

The hotend temperature sensor input support PT1000. When using one, make sure the PT1000 jumper is installed. Make sure it is removed when using a standard thermistor.

Also make sure you define the resistor value as R1000 in your M308 command.

You can also use the MAX31865 to connect a PT1000.

Initial Firmware Installation

The board that you will receive does come with firmware installed. It is suggested that you reflash the latest firmware anyway as the board you receive may have an older version of the firmware installed.

Download the file called Duet3Firmware_SHT36MAX3.uf2.uf2 from here.
To install the firmware, whilst holding the reset button, plug the Fly-SHT36 Max V3 into your PC and drag and drop the .uf2 file onto the rpi drive that appears. Follow the CAN Connection instructions to continue.

Updating the Toolboard Firmware from 3.5.1 Onwards

Using DWC, upload the latest firmware file to the system tab. Once uploaded, send M997 B124 and it will update (This assumes your board is the default CAN address 124, change the address in the command if necessary). The updating time (around a minute or two) is longer on RP2040 based toolboards so be patient.