This implements a mailbox sensor which sends emails to you when the door of your mailbox will be opened. It uses magnets to fix the sensor to the mailbox, so it will work only with metal mailboxes. The magnets are not too strong. The sensor will move, if somebody forces stuff into your mailbox. This is intended behaviour.

In addition to the 3D printed parts you will need:

• 1x Metal mailbox
• 2x Neodym magnets, 15x15x3mm
• 1x SmartHome Tür-/Fensterkontakt optisch
• 1x Fritzbox

The SmartHome Tür-/Fensterkontakt is mounted inside your mailbox and is registered as device in the Fritzbox. Any change the sensor detects will trigger an email sent by the Fritzbox to you,

Clean up the bore holes. Insert some white filament to fix the two parts together.

Use some dry adhesive to glue the magnets into the two holes.

Now slide the doors sensor into the holder. Then you can put the assembled sensor into your mailbox.

Here is an example how I registered the mailbox sensor in a Fritzbox.

If successfull the Fitzbox will send you emails with the following contents when the status of the sensor changes: