Ultra-low-power ESP32 outdoor porch security light controller with LoRa communication, PIR motion waking, ambient light sensing, and battery voltage protection.

![ESP32 porch light controller with SX127x LoRa module, PIR motion sensor, and VEML7700 lux meter](docs/images/hero.png)

**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](https://gitea.lab.audasmedia.com.au/sam/Porch_Security_Light)