I would love to connect with anyone that could help me with my floundering project. I’m trying to get an Arduino Uno to control 2 stepper motors independently so they turn a pair of wooden fans/blades (not fast). Thank you.
Welcome to the community! Dropping by electronics nights (open to the public on Thursday evenings) is a great way to connect with folks and get hands on assistance. Steppers are great for precise movement but lose torque as speed increases. Can you describe your project a bit more?
Thanks for your response!
I’m trying to make one of these:(https://youtu.be/MC0s2m80Gco)
but running off a couple of motors and an arduino uno. Started with dc motors & cogs - too fast, too noisy. Currently trying steppers and belt drive (not quite fast enough but quieter. Struggling with physics!). The “blades” would ideally accelerate to a speed of about 60rpm, but the current differential (not sure if that is the right word!) between driving wheel and receiving wheel is around 1:4, so maybe be fantastic!
In an ideal world the piece would be asleep until it hears a noise, which wakes it up and it performs for a while, then goes back to sleep if it’s gone quiet. The blades should rotate completely independently from each other so at any time the blades could be accelerating or decelerating, stopped and rotating in either direction.
I’m a total noob to Arduino and this sort of physics so any help would fantastic. Do you recon you could advise?!?
PS I will try and come this Thursday
That was a useful nugget of info you sent me earlier! I wasn’t aware that torque reduced in steppers as speed increased. It totally explains why, currently, the blades are happy enough to start moving but appear to fail at higher speeds. Atm I’m just using inexpensive 28BYJ steppers with their little driver boards. Maybe I need a slightly bigger stepper that has a bit more muscle and a higher top speed. Prices of steppers seems to jump massively and I’m confused about suitable drivers…. Would prefer not to be spending a lot on steppers which are probably designed for far superior accuracy (unnecessary in this case). Also don’t want the box behind the blades to be too large….
I would bounce some ideas off the folks at electronics night. Using an RC ESC (electronic speed controller) and dc motor could be a good route but not sure how it would fit with your noise requirements.
Hoping to get some opinions this Thursday!
Hi Julius, you might try taking a look at the book Making Things Move. If I recall it has some useful info about selecting motors and calculating torque requirements.
This may be useful for getting around the speed/torque issues: https://everythingsmarthome.co.uk/howto/converting-the-28byj-48-stepper-motor-for-more-torque/
Wow! Great find!
Have ordered some A4988 drivers.
Hope we could see results next Thursday.
This project uses stepper motors to create a clock (so they have the same challenge as you - driving two hands off a single axle). They have managed to get all the mechanism inside the box, which may help you to do the same for your project.
Actually his setup with the steppers turning one set of cogs in front of the faceplate, and one behind the face-plate is very similar to my setup - except I’m using belts.
It would be interesting to try with the larger cogs like he used, which i believe he laser printed specially.
So I blew up my arduino last night! Thanks to Ian for diagnostic skills - otherwise I’d probably be still tinkering with code and repeatedly plugging/ unplugging it in over and over again. Have ordered a nano so we’ll see if I can blow that up next week!
hoping to see Iain this Thursday as I have acquired an Arduino Nano board and would love to get the steppers twirling with his help!
Great working with you last night!
Here’s a good tutorial on an improved stepper library that might make it easier to get what you want with acceleration curves . The setAcceleration command looks useful. You can take a look yourself or we can give it a try next Thur.
I hope to try this later today.