motion sensor w/timer

[7echo]

Hi,
I posted this question on another site and was referred to you all. I tried searching, but the language you all speak is beyond me.

Short version- I want motion to start a timer that will run for maybe 5 minutes, then start a small exhaust fan to run for a couple of minutes.

Long version- As part of a remodel I want to set up an automatic exhaust for a cat litter box. The box will be under a counter. Kitty does his business and starts the timer(don't want the fan to come on and scare the critter, that could cause problems with the cats finding other areas to do their bidness) the fan comes on after the timer runs, and runs for a programmed amount of time to vent the area. I will run this off 110 v power. The fan will be a quiet one, probably less than 1 sone. Maybe a standard bath fan, or something from Greenheck. I can cipher out the cfm, flow, etc., just need help with figuring out the controls parts. I would prefer to buy standard components that will fit in gang boxes, but am open to options.


Thanks in advance!

 

[user_88]

The web page below has some circuits that might be useful:


However, there could be some effort involved in the interface between the different components or phases of your objective.

....Initial cat detection, set off by the electric eye circuit alarm ... turns on 1st time delay ... waiting for cat .... 5 minutes or so ... (this is one timer circuit)
followed by activation of Fan ... on for a few minutes ... (this might be a relay of some sort, activated by another timer circuit).
Finally, after the entire cycle is complete, you would want to reset the Electric eye detector....(maybe another timer circuit ...20 minutes or so).
so that it would be ready for the next event .....

Another possibility might be to consider using a microcontroller.
There is a product called a 'STAMP' controller, which is fairly simple to program, using a version of the BASIC language, and would allow the timing and sequencing of several input and output pins to accomplish your objective.

... not sure if you will find any ready-made or off-the-shelf solutions to this particular
problem.