The crucial difference is in the use of laptop keyboard key cap, which are already low profile and have a flat base. Broken laptops should be dime a dozen now days - I have 2 broken thinkpads under my bed right now, waiting for the arrival of the next batch of rare earth magnets.
Step 1: Required Material and Tools
- Keycaps from a laptop keyboard, or other similar low profile keyboard. I used the keyboard from the Dell Inspiron 7800 (I think). Just pry them off with your fingers, should be no problem at all. Make sure not to lose any though!
- 8mm circular rare earth magnets, like these. You are going to need around a hundred or so, depending on the keyboard.
- A tube of super glue, you won't use much of this.
Step 2: (Optional) Wash Keycaps
Warm soapy water in a bucket should do the trick. Just rinse and scrub each key. Avoid using solvents.
Step 3: Attach Magnets
- flip keycap over
- add a drop of super glue in the centre. You don't need much super glue, a drop 1/3rd the size of the magnet should do fine.
- drop the magnet in
- rinse and repeat for the other 100 or so keycaps. Should take around 15-30 minutes depending on how quick you are and the number of keycaps. Siblings or friends or family accelerates this process considerably :D
A few tips: try to keep the roll of rare earth magnets as far away as possible. These things are darn strong, and a single magnet will fly 20cm or so to reattach itself to the roll and in the processing flinging fine droplets of super glue everywhere.
The way I do it is as follows:
- hold the roll of magnets in my left hand, near my left hip, so it is about 30cm from the surface of the desk
- flip a keycap with my right hand
- pick up super glue with right hand, add a drop to centre of keycap
- slide off a magnet using my left thumb
- pick up magnet using right hand and drop it in the keycap
You will notice that once you have a keycaps with magnets lying around, any new magnets you drop in will be attract to them, and go off centre. This pretty much can't be avoided unless you have a big desk, or periodically pick up all the keycaps and put them elsewhere.
One final thing: it probably helps to have all the magnets oriented the same way. This lets you stack the keycaps by taking one and using it to suck up all the keycaps on your desk forming a stack. This is a load of fun, but if you have some magnets reversed, they won't all stack in the same direction. No biggie, but it's nice being consistent :)
Step 4: Attach to Fridge, Arrange in Pleasing Forms
I recreated the keyboard layout as a way to check for missing keys. You will need a few more keyboards to get a good selection of keycaps to make decent length sentences :)