Pop open kitchen cupboard doors with solenoid

[kp278]

Hi, we're installing a kitchen and while considering door handles, soft-close, push to open, etc etc I had one of those ideas that is far more sophisticated then we need and will inevitably prolong the pain of fitting a kitchen; I wondered if I could use an electromagnetic solenoid or car-door type lock solenoid to pop open a kitchen cupboard door, with either a light sensor or capacitive touch to activate. The door would only need to open enough to make it accessible by hand, the theory being that a light sensor could be mounted under the edge of the worktop so as you reach to open the door it would pop open. My first problem is I don't know what strength solenoid I would need to open the door - a google on solenoids offers up all kinds or throws and strengths. A electromagnetic would be preferable to a car-type motorised solenoid as it seems I would need to reverse polarity to close the solenoid after each open, which adds an extra element not required with an electromagnet.

Thanks!

 

[Diver300]

Solenoids aren't very good where you want a force that is constant over a distance.

I suggest a motor. You can set the gearing of the motor so that a spring will return it if you remove the power. That is how most of the door-release motorised "solenoids" on cars are arranged.

You will need a timer with a solenoid or motor so that they are not left energised continually.

As you will need a timer, it's really not much more work to have a servo-motor operate when the person is sensed, and then return after a fixed time. A servo motor would let you adjust how much the door opens, and at what speed. A solenoid or motor could be a bit harsh and noisy.

The door handles on my car are flush and come out when the car is unlocked. They use simple dc motors to push the handle out. The mechanism is arranged so that when the motor returns to the retracted position, the handle can stay out with only a spring pushing it closed, so that trapping someone's hand isn't an issue.

You will need to measure the force to open the door.. You could use one of the scales designed to check your luggage is OK to go on an aircraft.

 

[augustinetez]

Dont forget, in a power failure, you won' be able to get in to your cupboard unless you have a back up power source - another level of complexity.

 

[Diver300]

Dont forget, in a power failure, you won' be able to get in to your cupboard unless you have a back up power source - another level of complexity.

I don't think that is a major problem. Cupboard doors are probably just held shut with a spring and it's easy enough to get something around the edge to pull the door, or use a suction cup.

 

[rjenkinsgb]

I had an idea for this in the middle of the night:-

If you got a small concentric-pole type solenoid magnet and a "cup" or "pot" style screw fixed magnet with exactly the same outer diameter, the solenoid would just act like a piece of iron when off and the magnet would pull to it.

Power the solenoid with the correct polarity (so the poles repel the magnet) and it would pop the door open.

No moving parts!

You could add a brass shim or rubber pad to space the two apart if the holding pull was too strong.


Examples of the styles of items, though these are much larger than I'd think to be practical - probably 12 to possibly 20mm would be nearer appropriate?

DC 12V 10KG Lifting Holding Round Magnet Electromagnet Solenoid 30mm Diameters 609876050722 | eBay

Description: Lifts steel/iron that has a smooth, flat surface. 100% brand new and . Used widely in home appliances,vending machines, game machine,matic control system, etc.

www.ebay.co.uk

10 Neodymium Cup Magnets 95 lbs Pull Capacity Each, 1.26 inch w/Matching Screws | eBay

Find many great new & used options and get the best deals for 10 Neodymium Cup Magnets 95 lbs Pull Capacity Each, 1.26 inch w/Matching Screws at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

 

[augustinetez]

Here's a commercial option https://www.blum.com/au/en/products/motion-technologies/servo-drive/overview/