You will need:
1) Reed switch is a glass tube with contacts. When holding a magnet to the reed switch, it closes the contacts. You can get it by disassembling the reed relay, there are also reed switches in the door closing sensors for alarms, etc.
2) vibration motor from a broken mobile phone.
3) Battery of small diameter. In order not to reinvent the wheel with a crown, I suggest just buying a "mezinchik" battery.
4) A little magnet.
6) and so on. . .