Smart doorbell
A battery-powered ESP32-CAM doorbell that photographs visitors straight to Discord.
This is a smart doorbell built upon the ESP32-CAM module, which instantly captures a photo and sends it as a notification to a Discord server when the button is pressed. The device is optimized for maximum power efficiency using deep sleep mode while also providing immediate, hardware-level feedback through light and sound.
Backstory
A battery-powered smart doorbell built around an ESP32-CAM. Press the button and the hardware fires the LEDs and buzzer immediately, without waiting for the chip to wake, while the ESP32 boots, connects to Wi-Fi, snaps a photo of whoever's at the door, and pushes it to a Discord channel via webhook before dropping back into deep sleep. The interesting part was the electronics around it: a transistor acting as an electronic relay so the tiny touch signal can safely switch the high-current LEDs, a resistor divider that scales the 4.2V battery down to safe ADC levels so the firmware can estimate remaining charge, and a hinged battery compartment so swapping the 18650 cell doesn't mean tearing the whole thing apart. Deep sleep keeps it going for a long time between presses.
Highlights
Instant hardware feedback — LEDs & buzzer fire without waking the CPU
Deep-sleep power optimization
Photos pushed to Discord over Wi-Fi
Battery level monitoring via voltage divider
Tool-free 18650 swap (hinged compartment)