Detect Vibration.

Projects General Guidance
1

Hi,

I have been banging my head and waiting for numerous sensors for months, so I thought I would ask for a little bit of guidance from the experts.

Sounds very simple so here it goes. I want to detect if a car is running. I am using vibration to do this, but getting useless results.

I have tried the following vibration sensors

Piezo Disk Vibration Sensor
Piezo Vibration Sensor - Large with Mass
Grove - Piezo Vibration sensor

I am using the code
http://www.seeedstudio.com/wiki/Grove-_Piezo_Vibration_Sensor
And do get the same result 14 - 1023

But there can be no vibration and I get 1023
I can blow it sensor and get no result however I wipe my finger across it and get a 14 and more 1023 then usual.

any ideas, even not using vibration.

Thanks
Nathum

2

How have you wired it up?

3

How is the piezo element mounted and what is it mounted on? My understanding is that the piezo element has to change shape (flex, deform) to generate an output so touching it will do this but sticking it on a solid surface where the whole surface moves won't necessarily cause it to deform.

4

you'd be better off with an IMU. they come ready for serial connection to arduino.

they are used for the same thing in multi-copters.

5

Nathum:
I want to detect if a car is running.

Are you permitted to make any electrical connections to the vehicle? That would enable far easier approaches.

Otherwise, in order to detect vibration you would need a force sensor with some mass attached. (The sensor alone is unlikely to do much.) You could also try sound detection.

6

PeterH:
Are you permitted to make any electrical connections to the vehicle? That would enable far easier approaches.

Could try a hall effect type sensor placed in close proximity to the alternators output.
This way no direct electrical connection required.