So I'm trying to make a science invention but I don't know how to make it work. I plan on having someone sit on a toilet seat causing pressure. When the pressure is released a sound goes off that doesn't stop until the toilet is flushed. But how do I do this? Please Help!

Is the sound supposed to alert the person to flush before he leaves the bathroom?

Yes exactly

Seems like you would have to hook up something inside the tank (to the trip lever) and connect it to the seat (pressure). Are you okay with a wire/cord going from beneath the seat to inside the tank?

If possible it would need to be visible

The seat would have to be "soft" or flexible. A wooden or plastic seat would be too rigid and wouldn't "notice" the pressure. (I'm thinking the pressure-recording device would have to be UNDER the seat.) And you don't want any alerts while the person is using the toilet (and scare him) .

Would just a noise be enough of an alert? The person wouldn't understand a noise and might think something is wrong with the toilet. Too bad it couldn't be a recording, "Please flush, please flush, please flush" that would continue until flushing happens.

I understand what your saying but I'm desperate and have a short amount of time to finish this project

When is it due? How long have you been working on this?

I PMed two of our Plumbing guys to look at this thread and tell you if this is even possible. This is YOUR project, so I warned them only to give you hints, not tell you how to do this. I don't know when they will be online (they come on several times a day), so check back now and then.

One of the Plumbing guys PMed me with this:

"this would be more of a electronic question whether than a plumbing question. But if I had to improvise. I would put a context switch in the seat that connects to a normally open relay. This will activate a sound,(could be a quiet Bell or buzzer) that only quits when you push the flush lever."