Hi,
I am thinking about starting to play with the Arduino, but yesterday when thinking about possible applications, one thing immediately came to my mind where I could use some automation - I would like to open/close the sliding closet doors.
Now the electronics and programming I'd say are no problem, but about the mechanical part and general usability... I am not sure, looking a little bit on the net I found solutions with threaded rods, cogs and chains, pneumatic sliding door etc. What is the preferable way to move objects like a door? Are there any existing projects that I could look on for start? Any advice would be appreciated
To put a little more info - there are 3 doors, rolling in 2 lines, each door opens one segment of the closet, so there are 3 possible open states and 1 closed. E.g. here is diagram of closed doors
+++++---------+++++
---------+++++---------
Each door is 50cm wide, and i'd say the time to open should be 2-3secs max.
The biggest benefit would be that sometimes after shuffling the doors a few time I end up with this kind of setup
++-
+--
and if I want to get into the left-most segment, I end up moving 3 doors... which sucks. Anyway it doesn't have to be ideal solution but more like a playground I know it might very well be a failure in the end
DC motors run pretty fast, so you'd probably need to get a gearmotor, or use an extra set of belts & pulleys to slow it down.
Stepper motors are more controllable, so they can run slowly but they are a bit trickier to run and they tend to be noisy. (Although you might like that "high-tech" whine of a stepper motor!)
Servo motors won't work because they don't rotate 360 degrees.
I think the tricky part would be installing, fitting, and hiding the mechanism so that it looks good.
I'd mount motors and bump sensors on the inside of doors; the two doors on the single track would then know when they "bumped" together, or on the ends - and the other door would know when it was at the end.
Then, use a stepper motor on each door, and a long piece of cogbelt (not a loop - just a long single length - either bought bulk, like for a 3D printer, or take a standard belt and cut it) as a "track" (with idlers and such to keep the cog on the steppers in contact with the belt). You should only need one belt for each door track (so two belts) - two of the doors would run on the same belt.
Provided that the doors are on smooth running bearings and tracks, you shouldn't need very powerful steppers - 100 oz/in steppers should be more than enough.
This would likely be the lowest cost and easiest to implement solutions; most of the parts could be bought off Ebay - look for "3D Printer Stepper Motors" and "3D Printer Cog Belt".
thanks for the tips... the stepper approach with the track seems like a plan or at least a try. I think the 100ozin should be enough,
EDIT: so I measured and the force to move the doors is only cca 25N max... so even a weaker motor should work
last few days I looked up some infos about the stepper motors and drivers, I was mostly confused about the speed/torque, couldn't find the speed info on the motors I found on ebay. Only later found out I should look on the torque/speed curve but that is also missing on most motors on ebay... So Im not sure what to buy, something like this motor could work?
second thing was the driver, now I understand the most important is the current that the driver can supply, and there are problems with overheating...
would this small driver or do I need something stronger?
I am planning on ordering one motor+driver, plus some cog and belt to start playing with, so any suggestions are welcome.
I know it might very well be a failure in the end