What's the simplest way to check vibration with Arduino? Use a vibration sensor from DFRobot. You can directly plug it on our IO Expesion Shield V7. Just vibrate this sensor, Arduino can receive a digital signal. It's easy to acount and program in Arduino.

Despite it's simple, you can make full use of it with creative thinking, like step counting, Crash warning light and so on.

Inprovement

• Wide voltage range from 3.3V to 5V
• Standard assembling structure (Times-of-5mm Center distance between two 3mm mounting holes)
• Easily recognitive interfaces of sensors ("A" for analog and "D" for digital)
• Icons to simplely illustrate sensor function 
• High quality connector
• Immersion gold surface

a simple Pedometer device that can count your step

• IO Type: Digital
• Switch life: up to 10 million seconds
• Open circuit resistance: 10Mohm
• Supply Voltage: 3.3V to 5V
• Interface: Digital
• Size:22x30mm (0.87 x 1.18 in)

• Wiki (DFRobot Digital Vibration Sensor)
• Schematic

• Sensor x1
• Digital Sensor Cable (SKU:FIT0011)  x1