Hi there, I’m building an indoor golf simulator, and as part of that, I have an impact screen (think large projector screen) that I need to raise / lower. I’ve got the screen mounted on a 2" diameter mild steel tube sitting in pillow block bearings - so it rotates freely. On the end of the tube, I have a sprocket mounted (30 Tooth 08B Simplex Taper Sprocket to suit 1/2 Inch Pitch Chain)
I’ll be raising and lowering a screen made of approx 750g/m2 fabric from the pipe down 2.7m to the ground. So when fully extended, the first rotations need to lift ~6kg of weight. So 58N, if I’m thinking about it the right way. And the radius (let’s assume 3” - 1” for the pipe and then 2” more for the fabric wound around it). So 0.076M x 58N = 4.48 Nm
I’m planning to us a chain around the current sprocket and run down to a [x] tooth sprocket that I can mount to the shaft of a worm gear stepper motor with grub screws to the shaft. (am I going to have a connection issues with grub screws? do I need to key the shaft?)
I want to be able to control speed and direction and start/stop as needed. I’m happy to hold button as it goes, I don’t need it to ‘know’ when to stop/start.
I want it to hold position without requiring power (so worm gear, right?)
Thinking something like this:
- Nema23 work gear motor - https://www.robotdigg.com/product/567
- But I’m trying to figure out the right size / power setup
- call it 2.5” radius on average, 15.7 inch circumference. Need to lower 2.7m of fabric (106 inches) - so 6.75 rotations if I got a matching gear for the other side of the chain. More/less if I got a different gear to attach to the motor.
- I’d say target 30 seconds or less to raise/lower = so 3-4 RPM. Or if I go with an 8 tooth gear on the motor, I’d get 4rpm at the 30t gear with 15rpm at the motor.
Parts list, as I see it:
- Worm gear stepper motor - I’m struggling to find a site / way to search for something with the right combination of RPMs and torque - suggestions on motors or places to look?
- I need some sort of button/dial setup for controlling it (guessing those can be had pre-fab without having to buy the individual elements?)
- I need some sort of controller (raspberry pi/otherwise) - I’d guess this is a common enough application that I don’t need to actually code my own setup and can buy this prefab? I’ve done DIY coding with particle photos and built my own iOS and web apps, so I can if needed, but feel like that could be avoided?
- I need some sort of power supply that I can connect to the mains (UK) power - what do I need for this sort of setup?
Overall, I’m a pretty capable DIYer but haven’t done anything with gears and motors, so am lacking a bit of context and examples. I’ve done a fair bit of research and reading on my own, which has gotten me to this point, but could use some experienced advice. Thanks!