Cat Be Gone

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The concept:

  1. Motion sensor controls 24VAC irrigation valve
  2. Drip irrigation line sprays cats
  3. Cats leave

Control system requirements

  1. motion sensor
  2. valve controller

It could be free standing, probably easiest, or it could be a Home Assistant thing.

I think it should be free standing and later on it can have a WiFi connection to upload activity data so I can make a dashboard replete with colorful statistical charts. Maybe it can trigger a camera too. Later.

The valve controller can be a dry contact relay with TVS protection against spikes.

It has to be in a water tight enclosure, because we're in Astoria.

24AC transformer at house -> low voltage zipcord -> full wave rectifier -> buck converter (MPJA 30148, up to 40V in, adjust for either 3.3 or 5V output)

TVS

I need one that is around 5.5VDC unidirectional to protect the controller. And a bidirectional one for the valve that's around 36VAC

SMD, more hip or thru hole, easier to wire up

Sources, OpenSprinkler

TVS

  • Littelfuse SMBJ43CA SMB suggested by OpenSprinkler, probably a little on the high side voltage wise
  • Littelfuse P6KE39CA leaded

I ordered some logic-level triacs from STM that are already overvoltage protected. I also ordered some thru hole TVS diodes in case I go for a dry contact relay set up at some point.