Hey there everybody I’m Cal and am super new to Arduino. I’ve been into programming for a long time, but only software stuff - I’d never hooked it up to some hardware. But, a friend of mine needed a fake CCTV camera to be hooked up to a stepper motor, so that it can be controlled with an RC transmitter. I’ve always wanted to learn about this stuff, so I said I’d give it a go
I’ve gotten quite far - everything seems to be working, the last step is hooking up the motor to the camera.
The reason I’m posting on here is to ask a question (and please let me know if I’ve posted this on the wrong board).
I have an 11.1V Lithium polymer battery (SiGP) and a NEMA 17 stepper motor. I only discovered after some testing how hot the stepper motor gets when it runs. Fortunately, it’s not hot enough to melt the plastic on the camera. Today I decided to put the components into the camera and get an idea of how it would all fit. It all looks good, but my problem is - there is no way to fit everything in without the stepper motor touching the battery.
As I say, I’m very new to this, and batteries freak me out . I definitely don’t want an explosion or fire hazard in this project. The camera will be used for around 45 minutes at a time, with long gaps in between uses.
So, long story short, is it safe to have a LiPo battery touching a stepper motor? It’s a very confined space and I will definitely need to drill some ventilation holes, but I thought I’d come to you guys for some advice.
Thank you in advance! Any advice is greatly appreciated
What voltage does the motor require and at what current, these need to be adjusted. They are probably OK and your voltage may be at the lower end. Touching is probably OK as long as it is not an electrical contact, my preference is not to touch.
Do you have a suggestion for an alternative? If the battery was much smaller, I could fit it elsewhere, but I liked the idea of the LiPo battery because - 1 its voltage was perfect for the Arduino and motor and 2, it could last a long time and be easily rechargeable. Would I get the same results with a regular 9V battery from a shop?
What stepper driver are You using? For what stepper current is it set?
If You dont need ay holding torque You can disable the driver outputs when there is no stepping. That reduces the heat a lot.
I think some insulation could fit in there . Would that be enough? I had a look at some fibreglass online and it does look very thin Is there a special type that I should look for or anything?
I'm using an A4988 driver . By "For what stepper current is it set?", do you mean with the potentiometer screw thing? It's set to 3.2 Amps.
As for disabling the driver inputs - I had thought about that, but it does need to be stable when not being moved (I don't know if that would work when the outputs are disabled?). As a side note, there are 3 pins on the driver that I wasn't sure which would be used for that. There is an ENABLE pin, an RST pin (Rest maybe?) and an SLP pin (Sleep maybe?). I would love to optimise the code to make it cooler though! Thanks for your input
From the steppers I've handled and used that is likely way to much current for both the driver and the stepper. Please post the datasheet for exactly Your stepper.
No surprise the stepper gets hot. The driver ought to be glowing too.
Could by pen and paper make a drawing of the driver - controller connections?
ENABLE is the driver output control. The other ones I've never tampered with.
This is my attempt at making a schematic in KiCad (I've never used it before, so it might make no sense . Note, I (in real life) connected the stepper motor wires using trial and error, so I have no idea if the schematic has it connected correctly.
I also didn't know how to add my RC receiver into the schematic, so it has been omitted, but it is powered with 5V and ground on the Arduino and controlled with Digital pin 2.
Oh, and there is a capacitor in parallel in there between the power and the stepper motor driver - I also didn't know how to add that
Thanks!
Bad news. You've got a hybrid stepper motor. It doesn't work well with a current controlled driver. A MOSFET H-bridge and 12 volt supply would be better. I never handled that kind of stepper so there might be holes in my arguments.
Lets wait for some other helper joining in.
Somehow the drawing refuses magnification here and the small characters makes trouble.
There are many thicknesses available, of course. I suppose I would figure the thickest piece you can find, practically. But then you did say that without there's contact between the two and you appreciate, correctly, there's something not right about that.
I don't want to be a Chicken Little or lull you into a false sense of security.
Oof, I have no idea what those things are - but I will look into it! Thanks so much for the suggestion . Hopefully some other helpers have experience with this type of motor.
Sorry about the schematic! I'll see if I can find a way to make it easier to read.
No, I appreciate it a lot! As I said, batteries freak me out, and I've always heard that making them too hot is a problem - I've just never known how hot is too hot . I'll have a look at some fibreglass and see what I could fit in.
I’m Cal and am super new to Arduino. I’ve been into programming for a long time, but only software stuff - I’d never hooked it up to some hardware. But, a friend of mine needed a fake CCTV camera to be hooked up to a stepper motor, so that it can be controlled with an RC transmitter. I’ve always wanted to learn about this stuff, so I said I’d give it a go 
