Quantity   Component name
1 × ESP-32 "Lolin-32" board with built in battery connector / charging circuit. Any web-connected board will do.
1 × Reed Switch
1 × Magnet Inductors, Chokes, Coils and Magnetics / Fixed Inductors, Chokes and Coils
1 × Lipo Battery I used the 400mah "Ideal for Feather" battery from Adafruit. Fit nicely.