PIR Cat Exhaust System (Name Pending)

A cat litter ventilation system utilizing an Arduino Uno and a HC-SR501 Passive Infrared (PIR) motion sensor.

System Parameters

1. Cat litter volume: 6ft³
2. Typical bathroom exhaust: 8 air changes per hour
   • 48ft³/hr to be cycled through
   • Will run 47 CFM fan for 10 mins

Circuit Diagram

System Diagram

Sequence of Operations (SOO)

1. Initial power up of the HC-SR501 PIR sensor requires 1 minute for acclimatization to the infrared energy in the room.
   • LED Red Indicator on 60S
   • Motion detected = 0
2. PIR Ready
   • LED Green Indicator on
     • If push button pressed during ready period, Fan will run for 5 mins
     • Push button is inactive during all Red LED times
3. PIR Detected
   • LED Green Indicator off
   • LED Blue Indicator on, delay 5min, motion detected = 1
   • 12VDC Fan powered on for 10min
4. PIR Reset
   • LED Red on 6S reset, motion dected = 0
   • LED Blue off
   • Fan off
   • Refer back to SOO #2.

Components:

1. Arduino Uno
2. HC-SR501 PIR Motion Detector
3. Coolerguys 120x120x25mm 3 Pin Fan 840556091929 Low
   • 12VDC
   • Running Amp Draw .1A
   • 47 CFM