“In this Instructable I show you how I made a battery powered sensor to monitor the door and lock status of my remote bike shed. I have nog mains power, therefor I have it battery powered. The battery is charged by a small solar panel.
The module is designed for low power operation and runs on an ESP-07S in deep sleep which wakes up and checks the door and lock position every minute. However, when the door is opened, the module is woken by a simple hardware circuit to immediately send the ‘door open’ information. The module communicates via ESP-Now, in which the transmission time is very short, requiring only a small amount of energy.
My home automation running on Openhab and Mosquitto handles the messages and sends my an alarming message via Telegram if the alarm is switched on.
All components are bought from Aliexpress.
ESP-07S module is chosen for the easy connection of an external antenna to increase the ESP-Now range.
TP4056 charger board with battery protection
18650 LiPo battery
Reed switch (NO to monitor door position)
Contact switch (monitor lock position)
Solar panel (6V, 0.6W)
Transistors, resistors, diode, connectors (see schematic)”