Automatic Chicken Coop Door - Auto Closes Coop - Beta Version 1.0 - Page 20

Your first drill is 18V... if you're going to go with a battery/solar charger setup you might want to stick with 12v drills - especially since the solar panel trickle charger you point out is for 12v systems.  (I have already bought that exact trickle charger btw).

Also, if you're planning on disassembling the drill to just use the motor, I've learned a few things there as well.  There are two different components in these drills, the motor, and a planetary gear box.   You'll want both.  But a lot of the cheaper drills have the planetary gears just set in the drill housing - which means you have to keep the drill housing.  Whereas more expensive drills often have a separate gear box which makes it easier to ditch the drill housing and have a much slimmer "power plant".

So if you want to ditch the drill housing, I'd look at some of the originally more expensive drill brands - Ryobi, DeWalt, etc. on Ebay that are cheap cause the battery packs are shot, etc.

Something else learned the hard way... when I disassembled my drill, I clipped out the trigger thinking that I would be controlling the drill speed via pulse-width modulation.  However, upon reflection, it might have been better to have kept the trigger and just used a zip-tie to adjust the trigger to the speed I want the drill to run at.... duh....   That would be easier, and easily adjusted to the final speed you desire for your design.

That's a good idea.  I don't think excessive speed is going to be a problem with the screw drive.  At 500 rpm and 24 TPI on the rod, you get about 1/3rd inch per second travel - so  a 12 inch high door should take about 35 secs to open/close.

But if you're thinking about a cord wrapping around a spool being driven by the drill it's a whole different ball game.  With a 1" spool and 250 rpm you're still closing the door in about 1.2 secs.   I think that's probably too fast to make sure the birds get out of the way etc.

I think the screw drive is a good solution for the guillotine type door, but I've got an "A" frame tractor with a draw-bridge type door on the bottom.  Using a screw drive on it is more difficult because the door actually moves in a arc when it opens and closes so a screw-drive with a fixed nut will probably jam as the alignment changes.  So I'll probably use a cord/spool arrangement, but then I've got to slow the drill way down.

I like the car antenna retractor too, but I need to know how much throw it requires and how much resistance it would provide to the door being pulled back open (since a draw-bridge doesn't ride in tracks).  Does anybody know these answers?  When everything is considered, I think the guillotine door is easier to automate.

check this out.www.hometech.com/hts/products/drapery/aa-aam80.html

sorry try this. It shows how to use a drapery moter to open and close the door with a timer.www.buildeazy.com/photo-chicken-coop-beatarticle.html

Nice design, great idea - I love it!

Is This cool or what!   Looks simple too. The moter is a little pricey, about 80 bucks. I was thinking of going to a shade place to see if maybe they had a used moter for cheap $$  You never know untill you ask.

Just my $0.02, consider using an acme threaded rod and nut if you're going with a DIY drill-based drive. This almost-square thread is designed for converting rotary to linear motion, where as hardware store v-threaded rod is meant only for fastening. You're less likely to have the mechanism bind due to poor threads, thread damage, dirt, corrosion, etc.. if you use acme rod.

Thanks for the interesting input - would you happen to know of any sources for this material?