31 lines
2.0 KiB
Markdown
31 lines
2.0 KiB
Markdown
Ultra-low-power ESP32 outdoor porch security light controller with LoRa communication, PIR motion waking, ambient light sensing, and battery voltage protection.
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**Status: in progress**
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### What it does
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* Wakes from ESP32 deep sleep on PIR motion (GPIO 13) or scheduled RTC wakeups
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* Measures ambient lux via I2C VEML7700 sensor to prevent activating porch lights during daylight
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* Drives high-voltage porch security light relay (GPIO 12) upon valid night-time motion
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* Transmits motion alerts, battery voltage (GPIO 34), and status via SX127x SPI LoRa radio
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### Bill of Materials
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| Part | Quantity | Purpose |
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| :--- | :---: | :--- |
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| ESP32 Development Board | 1 | Main MCU utilizing RTC memory and deep sleep wake pins |
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| SX127x LoRa Module | 1 | Long-range 915MHz SPI radio transceiver (CS GPIO 5, RST GPIO 14, DIO0 GPIO 26) |
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| PIR Motion Sensor | 1 | Infrared motion detection connected to RTC_GPIO14 / GPIO 13 |
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| VEML7700 Lux Sensor | 1 | High-accuracy I2C ambient light sensor for daylight lockout |
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| Relay Module | 1 | Solid-state or mechanical relay on GPIO 12 switching 12V/240V porch light |
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| Voltage Divider Sensor | 1 | Resistor divider on GPIO 34 for monitoring battery pack voltage |
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### How it works
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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.
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### What broke
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* 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()`.
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### Links
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* Gitea Repository: [sam/Porch_Security_Light](https://gitea.lab.audasmedia.com.au/sam/Porch_Security_Light)
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