Worst case scenario you have a relatively small, relatively high torque motor. That'll definitely find itself another use if it's not suitable for the door thing.

Discovered you can make a H Bridge using two relays. I happen to have a 2xRelay module which is now working as a H Bridge. Really really simple to use. If the relays are the same (high/low) the motor would be off. Set one relay high to turn the motor, swap which is high to change direction.

Eg
L/L & H/H - Off
L/H - Forward
H/L - Backwards

Super dull video

Arduino, 433 MHz receiver, relay module and hall effect sensor.

The idea is to have the motor running for x seconds, but if the hall effect sensor is triggered it stops. A bit of a fail safe to stop the motor in case it is already fully open.

Erm, I shouldn't have bought a rear wiper motor. Back to ebay (or hack this apart).

That's better. Ford Focus front wiper motor.

It's got quite a kick to it.

Your vid is private :(

Should work now.

Haha - they've got some real torque haven't they!

Bloody hell, it actually works.

Need to add the magnets/hall sensors - edit: added one for opening, works well.
Change the open/shut duration,
Support the upright better,
Possibly switch the side of the motor because it is slower in one direction compared to the other. I'd rather the closing direction be slower and more controlled.
Add some flyback diodes.

Used the an Arduino app on Android for the first time the other day "ArduinoDroid". Not the best app but still really useful. Saves disconnecting everything or bringing a laptop into the attic to tweak the sketch.

Current progress. Not finished, still waiting for magnets to arrive so I can finish off and paint, but working nicely.

That's very cool, not sure about the big cutouts that are still visible in the hatch though. Take it you couldn't do it any other way?

Yeah, that's the worst bit. I'm planning some sort of flap to cover them. Probably on a hinge with a magnet. They'll definitely be covered somehow. Got loads of MDF left to play with.

It's because of the way the ladders are mounted along with the door opening into the attic. If it opened downwards that would cover everything, but it's a massive door that I wanted opening upwards. The size and shape of the holes are due the opening angle.

First time I've played with this for ages. Forgotten how to connect up my USBASP to program the board.

My temp sensor has stopped working a while ago and I hadn't bothered getting it going again. Tonight I've added a diagnostic mode to it. Got a button on it which, if pressed when turning it on, sets the sensor to diagnostic mode. Then some LEDs flash to let me know if it's reading a correct temperature and if the data is being sent.

Before I had nothing to let me know it was even switching on.

Want to make a proper soldered board at some point. Got enough bits to make a few of them at least.

Grr. It stopped working again. Worked last night for only an hour, reset it this morning and it's stored after an hour again.

Did you remove the line of code that tells it not to stop after an hour?
 

Haha. I'll comment that line out later and try again :D

Loose connection I'm thinking. I had it running for about 5 hours last night, the lights had stopped flashing when I got back from the comedy club. Have it a tap and it came back on.

The new Pi Zero looks interesting.

Looks like I'll be buying some of those!

I'm sure I'll get some too, no idea what for yet.