A NEMA17 footprint, CAN(-FD) connected 'backpack' driver. Works with RRF, Klipper or custom firmware. Based on RP2350 and TMC2240.
Designed by Mettle & Byte in United Kingdom
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The Ultralight N17 is a RepRapFirmware and Klipper compatible expansion board, developed in collaboration with Millennium Machines. It uses CAN(-FD) to communicate with RepRapFirmware or Klipper (or …
Read More…The Ultralight N17 is a RepRapFirmware and Klipper compatible expansion board, developed in collaboration with Millennium Machines.
It uses CAN(-FD) to communicate with RepRapFirmware or Klipper (or anything else for that matter), allowing you to control a single bipolar stepper motor. It exposes one input port for an endstop (3 pin, PH 2.0) and one output port for any auxiliary device, e.g. a fan (2 pin, PH 2.0).
* 36V is the absolute max voltage the TMC2240 can tolerate.
Your INPUT voltage needs to be below this so there is enough headroom for back-EMF from the motor to be dissipated in the event of a sudden stop, without causing an overvoltage event. There is a 2 watt 'braking' resistor mounted on the board that is switched on during overvoltage events, and will dump power as heat until the voltage drops below 36V. Behaviour at these extremes is unpredictable so do NOT rely on it.
For each Ultralight N17, you will need:
As part of my work on the Millennium Machines team, I needed a solution to be able to control a turret-style toolchanger while using all 4 axes available on the control board we recommend, the BTT Scylla.
To keep the footprint and wiring complexity down, I decided that a "backpack" style, CAN-FD connected driver might work well - mounting on the back of the motor to avoid taking up any more space.
None of the options on the market seemed to live up to my expectations. Mainly, these prioritised IO density and/or footprint, or features for use on 3D printer extruders, did not support RepRapFirmware, or did not use a motor driver that could talk SPI, limiting their usefulness in the role I had envisioned.
There are not all that many options for "backpack style" motor drivers that also support RepRapFirmware, and this is my entry into the field.
The Ultralight N17 is designed to do a few things well, and nothing else.
There are also some other reasons why you might consider the Ultralight N17 over another available option.
The Ultralight N17 is, as far as I am aware, currently the only NEMA17 backpack driver based on the RP2350A and using a TMC2240 driver.
Why is that important? Well...
The RP2350A is reasonably quick and has a hardware floating-point unit.
The TMC2240 can communicate at high speed over SPI, like its bigger brothers the TMC2160 and TMC5160. Unlike the TMC2160 and 5160 however, it integrates the H-Bridge so there is no need for external hardware - making it incredibly space efficient.
With the expansion connector on the bottom of the Ultralight N17, this makes it perfectly positioned to tackle closed loop control on NEMA17 motors in an integrated fashion, allowing RepRapFirmware full control over phase stepping and closed loop monitoring.
I intend to release an expansion board containing an AS5047 encoder, which, along with software work, should bring a reasonably cost-effective, DIY-style closed-loop solution to RRF that will allow you to upgrade any NEMA17 motor and make it closed loop!
To be clear: These boards are NOT currently capable of closed-loop control and there is no guarantee that this will EVER be possible, although the hardware has been designed with this in mind. If you DO buy one of these boards, it is with the understanding that this is an open-loop only system as shipped and no guarantee of closed-loop support in future exists.
What if you don't use RRF? Well you can of course use it with Klipper, as the board defaults to UART mode, or you can write your own custom firmware using the pico-sdk and do anything you want!
You can flash the board using the RP2350s USB Mass Storage system for really simple and quick development.
I have always wanted an excuse to design and build hardware, and this was it! It turns out that designing a CAN-FD motor controller was a bigger job than I anticipated, but I have learned a ton, and turned out what I think is a pretty cool little device.
Mettle & Byte is my one-man endeavour, and the Ultralight N17 is what I hope will be the start of something special.
I have self-funded the prototype runs and the first production run, and at these sorts of scales, PCB production and assembly is NOT cheap. By buying from me you are directly supporting further development not only on Mettle & Byte hardware, but also Millennium Machines software (MillenniumOS, ArborCtl etc) and support, where we aim to bring open, cost-effective CNC milling to the masses.
I am not in this to make a bunch of money - I am in this to make things that I think are cool and that other people might like, while supporting myself enough to explore new hardware and software ideas and to be good to the people who trust me with their equipment.
A full manual is maintained on the Mettle & Byte Website, containing up-to-date pin-outs and configuration instructions.
As mentioned above, Mettle & Byte is just one person - me. I will provide best-effort support on the Millennium Machines Discord, and other members of the community may also be able to help out too. We run a pretty friendly ship over there!
You can also email help at mnb dot ltd if you are really stuck.
Buy with confidence.
Our Tindie Guarantee protects your purchase from fraud. Learn More
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