This instructable will show you how to make an easy low-cost sentry gun.

Step 1: Parts

For this project you need:

- a breadboard

- 7 jumper cables (male to male)

- Arduino Uno

- HC-SR04 ultrasonic sensor

- sg90 Servo

- Elastic pistol

Step 2: Wiring / Building Your Project

I do not have any schematic so i will describe the way of wiring:

Servo:

Ground to ground

VCC to 5Volts

Signal to Digital pin 9

Ultrasonic sensor:

Ground to ground

VCC to 5 Volts

Echo to Digital pin 13

Trigger to Digital pin 12.

If you want the code for this project, you can leave your email in the comments and i will send you it.

A video of me making the sentry gun:

https://www.youtube.com/watch?v=z9CosAJdVw0&feature=youtu.be

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If there are any questions, you can leave it in the comments.