Rosmo robot - BLDC

Creating a small modular robot with pluggable daughter boards.

Public Chat
Similar projects worth following
Modular Open Hardware robot. #SimpleFOC

A fully open-hardware robot for ROS2/ MicroRos & SimpleFOC 

A ‘grown-up toy’ micro-robot that can be assembled without soldering, with components available worldwide. For serious hobbyists, universities, R&D. Aiming at RVR niche 

Capable of driving 2x BLDC motors per driver board ~5A @24v. Stackable for 4x4, 6x6 control.

Using Feather profile & expansion modules as optional daughter boards.

Portable Network Graphics (PNG) - 250.55 kB - 05/17/2022 at 11:25



OctoCore ESP32 dev board

JPEG Image - 3.63 MB - 04/29/2022 at 09:18



OctoCore ESP32 dev board

JPEG Image - 3.75 MB - 04/29/2022 at 09:18


JPEG Image - 45.27 kB - 01/11/2022 at 12:30


JPEG Image - 1.23 MB - 01/11/2022 at 12:30


View all 10 files

  • 1 × BOM: Passive Components / Misc. Passive Components

  • Putting it all together

    Samuk10/05/2022 at 17:08 0 comments

    Rosmo is a project to make small openhardware robots for educational and hobbyist use. We aim to design capable robots which can be assembled without soldering. It’s a modular set of open-hardware components that can be assembled into robots of different complexity and price. It’s all based on ESP32 so should support MicroROS work.

    We value modularity. The project started working with the M5stack system. The robot you see above is the culmination of that work. We built a chassis, ESP32dev board and ESC in this 5cmx5cm profile. We learnt a lot doing this. Unfortunately the parts crisis has meant that the ESC is not obtainable until at least 2023. We continue to test and develop using the small numnber of ESC boards we have produced.

    We also identified some issues with the M5stack system, in particular the header is hard to obtain at resonable prices. We’ve therefore pivoted our work to work with the Feather footprint to give a wider array of add-on boards. Whilst the Feather is great it is very small, so we’re also working with some slightly larger daughter boards using our own pinout in 6cm x ~5-10cm.

    We have some early drafts of this work underway with the Feather:bit board the intention is to use this board in two versions of a ~10cm x ~10cm robot.

    The first variation is Rosmo:Bot which uses cheaper brushed motors. Brushed

    The pinout at the rear is for daughter boards


    The second variation will be ‘Rosmo:BLDC’ using Brushless motors. We have a chassis and plan to use it initially with a very overpowered rp2040 ESC

    ROSmo BLDC

    The idea is the Rosmo:Bit PCB can be ‘upgraded’ by removing the wheels and attaching it to this chassis. It will provide mounting for the Microcontroller, sensors. In time we hope to use or develop smaller and cheaper SimpleFOC driver boards that are more suitable for this small robot.

    Software wise our intention is to run MicroROS/ROS2 on both the Rosmo:bot and Rosmo:BLDC. Initial work has started using Linorobot2. We’re waiting on a couple of upstream bugs to be fixed before this can progress.

    We’re also interested in supporting Smartcar_shield firmware on Rosmo:bot

  • Brushed motor board

    Samuk09/19/2022 at 20:19 0 comments

    This project is primarily about BLDC (brushless) motors.

    Since our ESC cannot be made at the moment (parts crisis) we've been playing around with a brushed version too

    Files are here:

    See how that fits together with our BLDC chassis here:

  • Parts are hard

    Samuk09/11/2022 at 20:27 0 comments

    So the parts for our ESC are unavailable

    Until we can get more we're going to play with an overpowered Pi2040 based board.

    Done a new chassis for it, waiting on some bits to arrive

  • More model tweaks

    Samuk06/28/2022 at 13:48 0 comments

    So I think we've finally got the body fitting correctly

    The encoders fit now too

  • More bodywork

    Samuk05/19/2022 at 23:30 0 comments

    More 3D work happening.

    Got a WebUI installed too, it doesn't yet do anything.

  • Time for some software

    Samuk05/17/2022 at 12:07 0 comments

    For the first time we got all the major components of Rosmo together and plugged them in.

    Various packages are in transit to Italy, Austria, Japan and Brazil so our early adopters can get their hands on them.

    We probably need to do some cases.. (and use shorter headers!)

    More photos on Twitter

  • Rosmo V2

    Samuk05/17/2022 at 11:32 0 comments

    So we decided to do a re-design of the body. This time we reached out to the FreeCAD community and built it in Freecad.


    It's almost there, just a few further tweaks.  The files are available in our Github repo

  • AS5048A Encoder Board available on Tindie $15.00

    Samuk05/04/2022 at 21:01 0 comments

    The encoders we needed for this project weren't available, so Richard made some:

    Ideal for small robots and motor control applications, this small sensor board measures the orientation of a nearby magnet (contactless measurement). It uses an SPI interface for communications, and can return angle values to 14bit precision – that’s 16384 counts per revolution, or 0.022° degrees.

    Its tiny 21mm x 17mm dimensions mean it will fit any project, and can be easily mounted even to tiny motors or actuators using the 2.2mm holes.

    They are now available on Tindie

  • Ottocore v2.1 getting made

    Samuk05/04/2022 at 20:55 0 comments

    So following on from the Opencore 1.0 board

    The Octocore boards have been made!

  • Motors move

    Samuk03/09/2022 at 13:21 0 comments

    Motors move for the first time

View all 17 project logs

Enjoy this project?



Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates