Hi

I need some advice on what kind of sensor to use with my ardruino. I need a sensor that will detect if the slightest of weight was dropped onto it. It doesnt need to measure the weight or do anything special.

So for example if a piece of paper was dropped onto the weight sensor it will register this and light up a LED thats it. Ive found a ton of load sensor etc, but nothing that will detect this light weight and for a reasonable price.

Any suggestions on parts?

Thanks in advanced guys.

Go through these links-
http://www.instructables.com/id/DIY-Force-Sensitive-Resistor-FSR/
http://www.instructables.com/id/FSR-Tutorial/
https://learn.adafruit.com/force-sensitive-resistor-fsr/using-an-fsr

 

Perhaps make your own. e.g. from a springy wire spaced a small distance from a contact? Paper dropped on wire causes wire/contact closure and LED to light. You might want to add a monostable or latching circuit to keep the LED lit for a defined time.

 

Or use a lever to amplify the force, and spring calibrated for the lightest weight you want up measure.

What exactly are you trying to accomplish? Maybe there's a different and better approach.

 

What's the lightest weight you want to detect, and how will the "scale" thing be physically put together?