Need sensor suggestion

I want to create a "buzz" noise when someone sits on a chair. Essentially, if such a sensor exists, I would like to embed it into the seat cover and when it detects weight then it would trigger.

I dont need to actually measure the weight, just know that there is weight.

Any suggestions on what I can use?

Thanks.

How about a pressure sensor?

music_connector:
How about a pressure sensor?

wiki:
A pressure sensor measures pressure, typically of gases or liquids.

I was thinking possibly a force sensitive resistor, (FSR).
They're very small, though, so if they do work, a few would be needed.
Adafruit FSR

"pressure mat switch" brought up a lot of possible items you could use.

Here's one from a surveillance equipment store.

Here's a 14" x 30" mat.

A smaller strip.

If you don't need the sensor to be very durable, it shouldn't be hard to make something like this using some conductive foam.

OldSteve:
I was thinking possibly a force sensitive resistor, (FSR).
They're very small, though, so if they do work, a few would be needed.

Yep, you're right. I was thinking along the lines of this: FlexiForce Pressure Sensor - 25lbs. - SEN-08712 - SparkFun Electronics -- flexiforce pressure sensor -- one or two would be enough, and very easy to implement.

music_connector:
Yep, you're right. I was thinking along the lines of this: https://www.sparkfun.com/products/8712 -- flexiforce pressure sensor -- one or two would be enough, and very easy to implement.

IMO, that wouldn't make a good sensor to embed in a seat cushion. That sensor would be better at detecting pressure over a small area not a large area like a seat cushion.

The datasheet shows how to use the sensor. The example circuit includes an op amp.

There are lots of DIY pressure sensor examples on the net. I think you could make a sensor for much less than $22.

Awesome guys.. thanks for the responses. Will do some research on the suggestions.

tyson22:
I dont need to actually measure the weight, just know that there is weight.

The cat will trigger it? A feather? A speck of dust? All 3D things have weight.

EDIT. Except for a 3D holograph.

Henry_Best:
EDIT. Except for a 3D holograph.

Ha ha. You beat me. :smiley:

Anyway, if the sensor is analogue, it's not hard to set a threshold level so the cat won't trigger it.

Henry_Best:
The cat will trigger it? A feather? A speck of dust? All 3D things have weight.

EDIT. Except for a 3D holograph.

"You have activated the Emergency Arduino Programmer Hologram. What is the nature of your emergency?"

I was thinking more Red Dwarf than Voyager. I don't think there are any cats on Voyager.

What about a simple button?

OldSteve:
Ha ha. You beat me. :smiley:

Anyway, if the sensor is analogue, it's not hard to set a threshold level so the cat won't trigger it.

Then he will have to measure the weight (to see if it's over the threshold and not the cat).
What he doesn't need to do is to record the weight.

We once had a cat that weighed 18lbs. You sure noticed if he jumped on your lap!

Henry_Best:
Then he will have to measure the weight (to see if it's over the threshold and not the cat).
What he doesn't need to do is to record the weight.

We once had a cat that weighed 18lbs. You sure noticed if he jumped on your lap!

Ha ha. Like my fat old dog. (Long gone now.)

And you're quite right, of course. You have to work out just what threshold to set.