https://www.instructables.com/id/LoRa-Tooth-Small-Wireless-Sensors/
**Parts!**
* SPDT reed switches: https://uk.farnell.com/hamlin/59140-030/magnetic-sensor/dp/1383368?st=magnetic%20switch
* SPDT magnets: https://uk.farnell.com/littelfuse/57140-000/magnetic-sensor/dp/1526531?MER=sy-me-pd-mi-acce&st=magnetic%20switch
* Battery holder: https://uk.farnell.com/renata/smtu-2032-lf/holder-smd-battery-for-cr-2032/dp/1216354?st=cr2032%20holder
* Battery: https://uk.farnell.com/varta/6032101501/cell-lithium-cr2032-230mah-3v/dp/300445?st=cr2032
* Boxes? https://uk.farnell.com/hammond/1551v1wh/enclosure-small-abs-white/dp/2985866
**Locations!**
(Doors - 7 total)
* Front door
* Snug door (2)
* Conservatory (2)
* Kitchen
* Garage
(Downstairs windows - 9 total)
* WC
* Conservatory (4)
* Kitchen
* Front room (3)
(Upstairs windows - 6 total)
* Stairs
* Bedroom
* Ensuite
* Bathroom
* Server room
* Office
22 needed. Consider 25?
| Item | Price 1+ | Price 10+ | Price 25+ |
|--|--|--|--|
| Reed sw| 3.84 | 3.60 | 2.88 |
| Magnet | 2.13 | 1.83 | 1.35 |
| Battery holder | 0.75 | 0.75 | 0.75 |
| Battery | 0.75 | 0.75 | 0.75 |
| Box | 2.15 | 2.15 | 2.08 |
| BLE module | 2.86 | 2.86 | 2.86 |
| Total
|----|---|---|---|
| Each | 12.48 | 11.94 | 10.67 |
Plus cost of ESP gateway to consider