2.0 KiB
2.0 KiB
Ultra-low-power ESP32 outdoor porch security light controller with LoRa communication, PIR motion waking, ambient light sensing, and battery voltage protection.
Status: in progress
What it does
- Wakes from ESP32 deep sleep on PIR motion (GPIO 13) or scheduled RTC wakeups
- Measures ambient lux via I2C VEML7700 sensor to prevent activating porch lights during daylight
- Drives high-voltage porch security light relay (GPIO 12) upon valid night-time motion
- Transmits motion alerts, battery voltage (GPIO 34), and status via SX127x SPI LoRa radio
Bill of Materials
| Part | Quantity | Purpose |
|---|---|---|
| ESP32 Development Board | 1 | Main MCU utilizing RTC memory and deep sleep wake pins |
| SX127x LoRa Module | 1 | Long-range 915MHz SPI radio transceiver (CS GPIO 5, RST GPIO 14, DIO0 GPIO 26) |
| PIR Motion Sensor | 1 | Infrared motion detection connected to RTC_GPIO14 / GPIO 13 |
| VEML7700 Lux Sensor | 1 | High-accuracy I2C ambient light sensor for daylight lockout |
| Relay Module | 1 | Solid-state or mechanical relay on GPIO 12 switching 12V/240V porch light |
| Voltage Divider Sensor | 1 | Resistor divider on GPIO 34 for monitoring battery pack voltage |
How it works
The system remains in deep sleep drawing microamps until the PIR sensor triggers RTC_GPIO14 or the RTC timer expires. Upon waking, it reads ambient light from the VEML7700 sensor; if lux is below MAX_LUX_THRESHOLD (50 lux) and battery voltage is above minimumPower (11.0V), it energizes relay GPIO 12 for lightOnDuration (30s) and broadcasts a LoRa packet.
What broke
- False wakeups caused by floating inputs on the PIR signal line during deep sleep were resolved by enabling internal RTC pull-down resistors on GPIO 13 before calling
esp_deep_sleep_start().
Links
- Gitea Repository: sam/Porch_Security_Light