Design help with light gate

Hi all.

I'm afraid I'm a woodworker by trade and I'm getting in over my head but I have a project and would love to solve it using a light gate.

I have 4 doors each 1500mm wide. I have trolleys going in and out of these doors all day long, when the trolleys go through the door they cannot return for a minimum of 10 minutes. Here's what I think I need programming wise

  1. When light gate interrupted, start timer
  2. If LG is broken before 10 mins, alarm sounds
  3. When LG is broken after 10 mins, timer resets, waits for next run
  4. Time to be displayed throughout
  5. Keyed reset switch in case of accidental trigger

Does that sound feasible and what gear would I need?
Thanks in advance

Welcome to the forum

How many trolleys are involved and does the 10 minute restriction apply to each of them individually or overall for any trolley ?

What is the size of the trolleys ?

Hi there!

The trolleys (20 or so) are all the same size, roughly 1200mm(w) x 600mm(d) and all trolleys must be parked for 10mins. It's a strict curing time. Will only ever be 1 trolley at a time in any given door

What's your budget?

No idea what something like this would cost to be honest. Would need to be reliable so not looking for a cheap solution

Just to be clear

One of 20 or so trolleys will pass through a door and a 10 minute timing period will start. Should the trolley attempt to pass back through the door within the 10 minute timing period then an alarm will sound

You can guarantee that no other trolley will pass through the door in either direction unless/until the first trolley has returned through it either during the timing period or after it

Are the 4 doors independent of one another or does the 10 minute rule apply to all of them once started by a trolley passing through one of them ?

Will the trolley return through the same door as it used on entry ?

Can anything, or anyone, other than the trolleys pass through the doors in either direction ?

Are the doors open all the time or does it need to open to allow the trolley to pass ?

The doors lead into ovens (around 50c) the foam on top of the ovens will then cure over 10 mins and be taken out, ready for the next to go in. the 4 ovens are separate and will need to work independently of one another. The alarm will let me know if the trolleys are coming out early (the problem we're trying to solve) Nothing else will go into the ovens.

*Foam on top of the trolleys

Would you be able to mount something like this on either side of the tracks and run some cables?

It sounds as though the doors open and close. If so it may be easier to detect this rather than detecting the passing of a trolley

Get some egg timers from walmart.

This sounds like somewhat of a harsh operating environment.
A hobby type Arduino may not provide a reliable solution.

The doors don't actually close during this time, hence the want for this system

Any suggestions on what may be suitable?

Ovens with doors that don't close ?

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It's a thing. Long story

If you want to stick with Arduino for some reason, there is the Arduino OPTA, a kind of industrial PLC.
Otherwise a plain old PLC (programmable logic controller) or PCA (programmable automation controllers) will do.

Do you have ANY experience with programming ANY type of PLC or microcontroller?

Zero!

Think I would detect if the trolley was IN the oven rather than just passing through the door, 2 break beam sensors in each oven looking crosswise, one near front, other near back.
What material are the trolleys made of?

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Well you have two choices, pay someone to do it for you, or start here:

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