Rosmo robot

The robot can be configured to use 1x 2x or 3x 18650 batteries https://rosmo-robot.github.io/

So thanks to Microblocks I have a remote control bot that can pick stuff up now. Still having problems with the ROS2 build, but nice to have some progress.

More info https://rosmo-robot.github.io/zio/

Some photos of the latest iteration. More detail, BOM etc on https://rosmo-robot.github.io/zio/

Still obsessing over a modular stackable system.

M10cube or Ruslan's building set both start from first principles, if we design everything from scratch how does it look.

I'm interested in a more pragmatic approach; How can we make what already exists work better together?

I've played with the M5stack format and kicked around using the Beagleboard pinout

Arguably the Pi Pico format is becoming a 'default' footprint for microcontroller work. It at least has the benefit of having plenty of pins.  It's a very narrow board though, not much room to play with.

So how does it look if we stick with the pico pinout (and maybe get a bit opinionated about how it's used, but break out the width to 28mm spacing?

The 'pico' one

Would be used as the compatibility layer between the narrow and wide spacing.

They could use short pins

They would be compatible with existing open hardware pico bits

Did a bit more playing around with https://rosmo-robot.github.io/learn-robotics/

I like the new XRP robot board from Sparkfun.

It's developed for https://experientialrobotics.org/

They have a nice curriculum for it https://introtoroboticsv2.readthedocs.io/en/latest/index.html

There's a bom and a basic PCB linked from https://rosmo-robot.github.io/learn-robotics/ for the 4wd version

Once we have the main 'Rosmo' chassis working, We may revisit smaller cheap(er) robots

- 9v > 3v3 conversion,

- £3 TB6612FNG motor driver 

- Pins at front are SPI & I2C in Breakout garden format

- Not much else

The Escornabot code based on five buttons seems good for young kids. We could adapt their button board to the 60pin stack

The MCU stack could be based on the Micromod:

Did some playing around with some 3D models

Opened some GitHub issuesto track the changes we need to make to the existing Smartcar lib. 

Playing around with the stacking concept in a slightly larger footprint.

Mo

Doing a brushed version first, then swapping out the motors board for a BLDC version later

Documentation

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.

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

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