18650 powered sensors

Hardware
1

I have literally hundreds of 18650 batteries left from my powerwall project

I need some door and pir sensors does anyone know any that take 19650s ? Can be ZigBee 433 or WiFi

Failing that will make some using mysensors framework but short on time at the moment

2

I’m using the mysensors framework and am happy with it for pir, temp, hum, lux.
18650’s are 3.7v , most arduino’s are 3v or 5v so you’ll need to contend with that depending on what boards you use.