Restroom occupancy logic,,, easy stuff

OK, I am pretty sure this is an easy project and I am kinda just adding it as an idea.

So a client of mine (Same one I will be putting the intercom into) has two public single occupancy washrooms with electric door strikes, which are controlled by one of many possible cashiers.

sooooo, I ran wires for a ceiling mount Motion detector, a recessed door contact and an indicator LED above each door to each washroom.

the logic being

IF door contact open followed by motion detected followed by door closed and more motion, someone is in the washroom.

IF on the other hand, there is motion followed by door open followed by door close and no more motion after 3 seconds, then the washroom is not occupied.

The purpose of this is to ensure the person pressing the button knows which washroom is available and cannot unlock an occupied washroom accidentally. Oh ya, the door strike unlock button will be bypassed if the washroom is in occupied status.

as a safety feature, I think I will make the light flash, or maybe trigger an indicator in the managers office is the washroom is in occupied status for too long. maybe someone passed out or maybe there is a fault in the system.

what product would you recommend for this? it really only needs 2 or 3 inputs and 2 outputs per unit. I could use one unit to cover both washrooms, but I am thinking of making this as a one room per board application. I haven't decided if I will have the Arduino control the door strike.... probably would simplify things.

An ordinary Uno, Nano or ProMicro could handle a hundred restrooms, if you added chips to handle all the inputs & outputs that would be needed. Just 2 restrooms? Too easy!

What's a "door strike"? A lock or bolt?

a door strike is an electronic latch released (or locked) by applying power to a solenoid. Alarm industry term. these are often called "door buzzers" because of the noise the AC powered ones make when the solenoid pulls in and out 60 times a second.

I know, 2 doors is easy, but that is all this project calls for. I could do it with the alarm panel, but I want to try something different :slight_smile:

Ok, I already recommended some types of Arduino. For the door strikes, a relay module sounds like the easy option. One Arduino could do both restrooms, but if you want to go with one per restroom, that's fine too. What else do you need help with? I would suggest your next step might be to draw up a schematic. Hand drawn is fine. If you don't know how to draw a schematic, just start with a system block diagram. Include part numbers and post links to the various components you have found that you think may suit the project. Read the "read this" post to find out how to post links properly on the forum. Don't spend money until we have checked components for you.