Simple Magnet Lock





Introduction: Simple Magnet Lock

Yes, it's another simple project you can do. I actually got this idea from this site while looking for things for my new nephew:

I figured out how to duplicate the lock idea that they had, but was unable to make one as small as they had. So after some time went by, I figured out how to make a magnet lock out of some materials that were lying around the house. Below you'll see the two different designs, but I'm only showing you how to make the one with the "Latch's Path". Unfortunately, you need a strong magnet to use this even for a thin door. I, of course, lack the strong magnet needed to operate this lock right now. You can see in the video that I was able to get the lock to respond, but the magnet was too weak to attract the latch all the way.

The thicker the material you use this latch on, the stronger the magnet you will need.
Movie is attached below...

1. Soda bottle cap
2. Plastic Shim (small piece of plastic/metal. Metal would probably work better to attract the magnet)
3. Drill and drill bits
4. Spring/Washers
5. Screw
6. Screw Driver
7. Metal pieces like small screws (not needed if you used ferrous metal for the latch)
8. Strong Magnet
9. Scissors
10. Solder Iron

Warning: Soldering Irons get extremely hot. Use with caution. Use in well vented area. Do not breathe in fumes from melting plastic.

These are ideal for locking the household chemicals away from kids while not having ugly locks in view on the outside of the cabinets.

Step 1: The Shim and the Cap

1. Cut a piece off of the shim so that it is longer then the cap.
2. Drill a hole in one side that is slightly larger then the screw you are using.
3. Don't do this step if you used a ferrous metal latch. Drill small holes at the other end of the shim and screw in the small screws.

1. Find the center of the cap.
2. Drill a hole through the cap that is smaller then the screw you are using.
3. Screw the screw all the way into the cap.
4. Melt or cut around the cap about halfway. This will give you a ridge or pathway for the latch.
5. Put the spring/washers on the screw and place the latch onto the screw.

Now all you have to do is install your latch into place using the existing screw. If you want to make sure it doesn't turn (the cap), melt a gap on the other side of the cap and install a screw down through it. Make sure you have a strong enough magnet to get the job done (or combine several strong magnets to use it on thicker materials).

Movie is attached to intro.
Told you it was simple.... Now all I need is a stronger magnet.

Two improvements:
1. Trim away the melted plastic with scissors.
2. Use a large flat piece of ferrous metal instead of the plastic shim or "melt" a metal washer into the plastic shim instead of the small screws to help attract the magnet.

Improvements are welcomed....



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    17 Discussions

    i have a suggestion regarding the magnet, why not use the magnet inside a hard disk?'s a very strong magnet . just find a broken hdd and get it from there

    I actually have the commercial ones that you linked to on all my kitchen cabs and will likely add them to the drawers that have sharp things in them soon. I can attest to the fact that the typical refridgerator magnet won't open them, of course how many geeks out there don't already have a couple strong magnets arround.

    1 reply

    I meant to respond to this before.... I'm one "geek" that doesn't have a couple of strong magnets lying around as you can tell from my instructables ;)

    I don't have anything with bluetooth. I thought of trying to do something wireless for the safe idea (so there would be no outside holes) but couldn't come up with anything (besides R/C circuits, but then there'd be a chance of interference from other devices). Your idea may work though. But I have no way to test it.

    I was suggesting the second of your descriptions, and you are right about it kind of being overkill for your requirements.I meant that when you held down the buttons one at a time, it would turn on each electromagnet.

    1 reply

    Still it would be a good idea for something like perhaps a shed door. This may also work on larger safes (not sure about smaller ones since the latch uses gravity to stay in the locked position).

    What if you used a series of electromagnets that "pulled" the latch around? Then you could rig those to a keypad, so that as you pushed each number, it would move the latch.

    2 replies

    Well I guess you could, but I wanted to keep this simple. You would also (If you're saying to use a electromagnetic key hooked up to a small keypad) have to have a power supply and make sure you position the key correctly (most likely, you'll have to put something on the outside of the cabinet door to align the key to the inside). Or are you suggesting to place the electromagnets in an oval around the lock and placing a keypad on the outside of the door? This too would be complicated, but pehaps I'll modifiy the lock to work this way for another project. This may work well for a safe door, but wouldn't work well just to keep stuff temporarily locked away from small children due to it's complexity and amount of space it would take up. Good idea though, I'll get to work on a design and post it here in paint...Be right back :)

    I ran into a dead end, so it make take a while to post a good design (not one of these crazy complex ones I keep coming up with).

    Heyyyyyy, That's Nifty! That's quite a cool lil lock, though it can be opened up by anyone with a magnet. lol. but it's still cool.

    1 reply

    Not really, you have to have an extra strong magnet (depending on the thickness of the door's material). Which is why the people in the link I provided said you can't use standard magnets that are usually found in households. They can't penetrate the material enough to make the lock move. You would need one extremely strong magnet or several together to make the lock work. This is the reason I showed the "workings" of the lock on a non-ferrous thin metal case with one of the magnetic darts (I tried with my 6x8 speaker magnet, but it was too large to move around inside the case) I'm going to update this in a minute though. I just tried the lock with one of the stronger magnetic darts and trimmed away some of the melted plastic with scissors. I now have video of the lock working.