Arduino Forum

Using Arduino => Motors, Mechanics, and Power => Topic started by: bobmcinnis on Oct 09, 2012, 03:58 pm

Title: Possible to lift a trap door automatically with an Arduino and winch-type motor?
Post by: bobmcinnis on Oct 09, 2012, 03:58 pm
Between my second floor and attic there are stairs but at the top there's just a trap door in the ceiling. It's heavy enough that it's hard to open if I'm carrying a couple of things with one arm. I'd like to have some sensor on the stairs that triggers a motor to pull up the door. I'm assuming I'd use a stronger motor/winch like device which will wrap up a cable or rope connected to the door.

Is there an existing project out there that might get me started? It looks like the hardest part for me at this point would be knowing how to connect to an Arduino a winch-like device that would probably have to get it's main energy from a power outlet. Any step-by-step tutorials out there for doing something like that or any general recommendations on which materials I'd need, even?

Me and my son are new to the Arduino and don't have a great understanding of electricity, I'm afraid. Any guidance would be appreciated.

Thanks,

Bob
Title: Re: Possible to lift a trap door automatically with an Arduino and winch-type motor?
Post by: solipsia on Oct 09, 2012, 04:59 pm
Hi Bob,

My immediate reaction would be to question whether you need an Arduino for this. You could just wire the power switch of the winch to a button on the stairs and press the button when you want the door to open.

If you want to use the Arduino, you might want to look at this product: http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCYQFjAA&url=http%3A%2F%2Fwww.pololu.com%2Fcatalog%2Fproduct%2F522&ei=9Tp0UNCtEeiq0QWMkoAI&usg=AFQjCNE3ngXsrSjZ5-eNyYgNYb8OXdMjoQ (http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCYQFjAA&url=http%3A%2F%2Fwww.pololu.com%2Fcatalog%2Fproduct%2F522&ei=9Tp0UNCtEeiq0QWMkoAI&usg=AFQjCNE3ngXsrSjZ5-eNyYgNYb8OXdMjoQ)

Alternatively, you could use the Arduino to power a relay (through a transistor), which could switch on and off a load plugged into the mains.

s.
Title: Re: Possible to lift a trap door automatically with an Arduino and winch-type motor?
Post by: CrossRoads on Oct 09, 2012, 05:05 pm
How about something like this
http://www.harborfreight.com/winch-with-automatic-load-holding-brake-2000-lb-electric-atvutv-68146.html
With 12V battery, and a battery charger.

Total overkill, but it does provide all the right pieces as one package for you.
Rework the switch into something you can step on turn on until released, and manually flip back to close.

Or this one -$20 more. but no messing with battery & charger & stuff.
http://www.harborfreight.com/110-volt-440-lb-capacity-electric-hoist-with-remote-control-40765.html
Title: Re: Possible to lift a trap door automatically with an Arduino and winch-type motor?
Post by: bobmcinnis on Oct 09, 2012, 05:15 pm
Thanks guys. CrossRoads, they are wicked awesome but you're right, a little overkill. I just tried to figure out the weight the winch would need to be pulling and it looks like under 20 lbs at it's heaviest point. I'm going to look for a lighter-weight winch but it looks like I'm on the right track now.
Title: Re: Possible to lift a trap door automatically with an Arduino and winch-type motor?
Post by: MarkT on Oct 10, 2012, 01:09 am
Using an Arduino does mean you can add limit switches, make it automatically close after a delay, add a warning beeper if its about to close, add a light sensor to stop it closing if someone's up in the attic, etc etc...
Title: Re: Possible to lift a trap door automatically with an Arduino and winch-type motor?
Post by: zoomkat on Oct 10, 2012, 02:55 am
You could get a linear actuator to raise and lower the hatch. All sourts of manual operating aids from gas struts like on hatchback cars, springs, counter weights and pullies, etc.