Introduction: Digital Vibration Sensor Using LM358
Working with sensors makes electronics better and easy to work with, there are thousands of sensors to choose from and designing sensors would make for cool DIY projects.
This instructable will be a part of a series of instructables in which I show you how to build sensors compatible with most microcontroller you can find. In the last two instructables I showed you how to how to make a tilt sensor and how to make a Touch sensor.
In this instructable I will show you how to build a vibration sensor, which could be used as a part of a security system.
Step 1: Tools and Components
Here is a list of what you need to get started with this instructable.
Step 2: Circuit
The circuit is quite simple, this circuit uses an LM358 IC which is an OP-AMP with an operating voltage range of 3v to 32v which is suitable to work with most micro-controllers. The circuit produces a digital output which gives a high pules each time a vibration has been detected.
Step 3: Vibration Switch
The vibration switch is built using uninsulated wire, you need to wind the wire on to a pen or any cylindrical surface. A resistor is placed in between the axis of the wire and when any vibration is detected the spring comes in contact of the wire and the circuit detects the contact and generates a signal turning on the LED.
Step 4: Senstivity
The sensitivity of the circuit can be changed by varying the 10K pot, if the LED remains on even when no vibration is detected, you should change the pot with a screw driver (plastic one recommends), until the LED turns off.
Step 5: Going Further
After you have tried it out on a breadboard you could build it on a PCB or as an arduino shield, for the spring you should use single strand wire. If you would like me to write a code for your microcontroller feel free to PM me.
In the next instructable I will show you how to build a photosensitive sensor.