Low-Power Motion-Activated Light

Overview

This is used to light a small room whenever movement is detected, using a PIR sensor (QB041/QB066 PIR), an esp32h2, fairy led lights and a bc337 to turn the lights on/off

Everything is battery operated (3xAA)

It is implemented as a finite state machine with 3 states and utilizes deep sleep to minimize power consumption

This is an alternative to https://github.com/mrnul/light

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States

STATE1 - Idle (Light OFF)

• PIR: PIR is LOW (no motion)
• Action: Light OFF
• Transition:
  • → STATE2 when PIR becomes HIGH (motion detected)

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STATE2 - Motion Active (Light ON)

• PIR: PIR is HIGH (motion detected)
• Action: Light ON
• Transition:
  • → STATE3 when PIR becomes LOW (no motion)

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STATE3 - Grace Period (Light ON)

• PIR: PIR is LOW (no motion)
• Action: Light remains ON
• Transition:
  • → STATE2 if PIR becomes HIGH (motion resumes)
  • → STATE1 if timeout expires

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Diagram

stateDiagram-v2
    STATE1: STATE1 - Light OFF
    STATE2: STATE2 - Motion - Light ON
    STATE3: STATE3 - No Motion - Grace Period - Light ON

    STATE1 --> STATE2: PIR HIGH
    STATE2 --> STATE3: PIR LOW
    STATE3 --> STATE2: PIR HIGH
    STATE3 --> STATE1: Timeout

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