What´s the best Arduino for my project?

Hey there, I have a little problem.. I am a furniture designer and want to make a bench that, once every seat is taken, starts to play music. But unfortunately, I have no idea about the electronic part of the project. I was wondering if one of you people coule please help me out and give me advice about which arduino would be the best suitable for my project and which other parts I need, like speakers and yeah, I don´t know..

I think the best kind of sensor for the "contact" in the seat would be one that feels weight so you can´t activate the bench by putting a bag on a seat (so no light sensor or something like that)

I´d really really appreciate your guys help. Eva

If you are new to Arduino the Uno is the best board to start with because most add-ons and most code works with it and it will be easisest to get advice here. Later, with more knowledge, you might decide to use a smaller board for your final project and keep the Uno for another project. That’s the simple part of the answer.

Checking if people are sitting on a bench may not be as simple as it sounds. What short of a bench are you talking about?

Is it effectively a flat timber plank with no soft covering and no backrest
Or ditto, but with soft covering?

Is it all timber with a backrest?
What style of backrest?
Is there softcovering on the seat? On the backrest?

You get the picture and I think a sketch of what you have in mind would help.

Are the people guaranteed to sit in predetermined positions or could a large person straddle 2 positions.
Is it full with 5 small people and also with 4 large people. (And by the way how many people can sit on it?)

I don’t think there is any obvious weight or pressure sensor that would be easy to fit - but I am certainly not an expert in that area.
Conceivably you could put load sensors under the legs of the bench and measure the total weight - but the weight of people is very variable so I can’t see that being a solution.

My inclination would be to use optical sensors even in spite of your concern about hats or coats triggering the mechanism. If you have a backrest the sensors could be high up so that small objects would be ignored. Light Dependent Resistors are very cheap, small and easy to use.

…R

The simplest design would be to design the furniture so that sitting on it caused a switch to close. For example you could design the furniture with an unglued loadbearing joint and include a membrane switch inside the joint so that it operated when the weight on the seat exceeded some threshold. Then use the switch to power up a recording/playback device. I don't know what sort of volume/duration you're aiming for, but cheap recordable greetings cards only cost a few quid. This approach doesn't need any form of microcontroller, just a few off-the-shelf components.

Must say I haven't tested this technique yet, maybe Capacative sensing could be a solution to check whether the bench is occupied or not.

Using just 1 resistor and a piece of metal plate/foil/wire mesh you can detect the presence of a person with it from a small distance. You can connect several of these sensors to one arduino to check each seat.

You'll probably do need to experiment with the value of the resistors and size of the metal plate.