Magnet ring phone mount

This requires that you have a metal plate on the back of your phone. You can buy adhesive metal plates on amazon for pretty cheap.

This is a ring that holds 10 8mm x 2mm magnets, which was enough to hold my phone securely. You can use this to turn any metal surface into a phone mount. I like to use it to hold my phone to the fridge, so that I can have a recipe open at eye level. If every other magnet in the ring is flipped, then it will be significantly stronger.

I printed this in PLA; there is zero tolerance in the magnet holes, which I found to be perfect or a slightly soft plastic. It's hit or miss whether or not the magnets stay in the holes, I had to glue in 0-3 of the magnets per ring, and sometimes that wasn't enough with the forces involved. Covering the ring with tape can help the magnets stay in, and helps the ring stich to the surface instead of the phone. I will likely release an updated version of this in the future.

UPDATE 1: I found that it works really well to cover one side with an even layer of electrical tape and trim the sides. This makes it look better, keeps the magnets in place, and the rubbery surface of electrical tape grips the phone better than masking tape or scotch tape. Double sided scotch tape works to stick it to a surface, but might not be necessary for magnetic surfaces. See the photos for how this looks.