It gets warm and humid here in the summer and feels too dry in the winter. To measure this I built up two MySensors Sensebender Micro boards and designed a 3D printed a case to go with them:

Final unit assembled

The holes in the case are to save on print time and let the air flow. The battery is far oversized and probably self discharges faster than the board draws current.

I ended up using a Raspberry Pi Zero with a RFM69HW as the gateway. It’s connected as a Ethernet gadget to my home server which lets everything run over IP while using a single cable for power and data.