Sonoff Zigbee Temperature Sensor SNZB-02 battery hack to replace the CR2450 battery with 2xAA batteries.

You also need the CR2450 battery eliminator and a 2xAA battery holder. You can use Flexing Battery Holders with Integrated Spring by Pixelle with the sonoff_temp_battery_hack_..._printed_holder.stls or a (commercial battery holder like this one on AliExpress) with the sonoff_temp_battery_hack_..._commercial_holder.stls - or you can edit the openscad file and adapt the battery holder dimensions, e.g. if you want to use 2xAAA instead.

The box can be printed without supports, I used 10% infill.
The lid needs supports, I used 15% infill.

To assemble:

• If you printed your battery holder: insert wires as shown at Flexing Battery Holders with Integrated Spring by Pixelle
• Solder battery holder to CR2450 battery eliminator. You should probably insulate the solder connections with tape or heat shrink tube.
• Put the eliminator through the hole of the lid (the side with the rivets is the outside and should be facing away from the 2xAA battery holder).
• Insert the eliminator into the sensor so that the wires touch the contacts in the SNZB-02.
• Put the rivets on the lid into the holes of the sensor. The button of the sensor should end up at the short edge of the lid closer to the hole. The distances between the rivets aren't equal so you can't rotate the sensor by 90 degrees.
• Put the battery holder into the box.
• Snap the lid on the box.

Updated lid 2024-02-19: Slightly increased rivet diameter for better fit with sensor.

Updated everything 2024-04-16: Changed the rivets because they broke off in some of my older prints. There's now two sets: one box and lid for commercial battery holders (like this one on AliExpress) and one for the printed holder from Flexing Battery Holders with Integrated Spring by Pixelle.