Help prototyping rotary bow for stringed instruments

Hi, I am looking for some guidance on a prototype I am working on. I’ve been using various types of robot wheels as a rotary bow for different stringed instruments. I’ll post an example video below.
So far I’ve been using a 12v 300 mm motor with this PWM Controller from Amazon

I want to make a similar motorized wheel bow attached to a dowel rod so that I can hit the strings with the wheel. (here’s a sketch: To do this I need to find a combination of right angle worm gear motor, a small controller and a small battery that could all be attached to a roughly 1/2" dowel about 12-15" long. Ideally it could have speed controller, either with a small thumb knob or Force Sensing Resistor. I know that FSRs can be very jumpy, so might not be the best thing for a wheel that has to have a pretty stable speed. Some kind of arduino approach might be feasible but I’m not super confident with that kind of coding.

For the motor I would prefer something small and quiet with a 3mm D-shaft. I have been putting the wheel directly on the d-shaft but if there is a better way to approach this with hubs and extensions, that would be great.

Any guidance or ideas for what parts might work here would be great. Browsing the site I get the sense that there are probably a bunch of ways to achieve this but I’m hoping not to overengineer as I focus on materials and playability.

Example of existing prototype, 3D printed pololu wheel design wrapped in synthetic horsehair
Scott Hampton on Instagram: "Workshopping a new track called “Light Inside the Body” with the new horsehair version of the Rotobow #rotobow #guitarviol #funk #viola #experimentalinstruments #hurdygurdy"


That sounds like a really fun project, and thanks for sharing the video!

Offering assistance with project design is typically beyond the scope of our technical support, so I moved your post to a discussion category in case other might feel more inclined to weigh in here.

Unfortunately, I do not have any specific part recommendations, but here are some links to some of our product categories that might be useful:

Once you get to the point in your design process where you have specific constraints and criteria for particular components, let us know and we might be able to offer more advice.

- Patrick

Ok thanks, I’ll put together a list of components and check in here to see if it makes sense.