Turn an RC Toy into a Robot

Stratos Botsaris shows us how to turn an old RC toy into a Spy Rover robot. This Raspberry Pi powered robot can be remote controlled from a smartphone, while you look through the on-board video camera.

TOY CONTROL

This Spy Rover project turns an old remote control toy into a surveillance robot with the Raspberry Pi providing the brains. It’s a great way to get to grips with robotics and network communication.

STEP 1

We start with a Big Bargain King Force Excavator toy, although you can use any similar remote control device for the project. Our digger with tracks is ideal for robotics as it has simple controls and a track mechanism.

STEP 2

Stratos removed the top half of the robot so he just had the tracks to work with. The flat surface on the top of the robot provides a base for the rest of the components. The heart of the operation is a Raspberry Pi 1 Model B.

STEP 3

The Raspberry Pi is placed inside a plastic case and an electronics breadboard is fitted on top. This is wired to the GPIO Pins using a breakout cable (using a device such as a Adafruit Pi T-Cobbler). This enables you to attach the rest of the electronics easily to the device.

STEP 4

Our Spy Rover wouldn’t be very effective without a camera. USB webcam is connected directly to the USB connection on the Raspberry Pi. An official Raspberry Pi Camera Module (raspberrypi.org/help/camera-module-setup) can be used instead, although it may not be as easy to position effectively.

STEP 5

A generic L293D Stepper Motor Driver chip is placed into the breadboard. This is used to control two DC motors independently, which is handy because that is the right and left tracks of our remote control device. Learn more about using the L293D with this Adafruit tutorial: bit.ly/1n7p5IV.

STEP 6

The whole unit is powered using a Universal Battery Eliminator Circuit (UBEC). This provides 5V from an input of 5.5V-20V and is capable of supplying up to 3A. Then a battery box of 6 AA batteries provides enough voltage of 9V to the UBEC.

CONTROLLING THE SPY ROVER

The Spy Rover’s motors are controlled using the Raspberry Pi (via the L293D Stepper Motor Driver). You can set it up to act independently, but it makes a lot of sense to act as a remote control robot.

STEP 1

It makes sense to use a controller with a screen so that you can see through the webcam. Rather than trying to attach a screen to a regular controller, it’s easier to add controls to a screen. Stratos built a controller app for Android.

STEP 2

The app enables Stratos to control the Spy Rover directly over a local network. The buttons on the bottom half send signals to the Raspberry Pi, which move the unit. The top half of the app streams the video from the webcam.

STEP 3

To move the Spy Rover forward the app sends a signal to the Raspberry Pi. To move forward, the motors turn clockwise and to move in reverse they turn anti-clockwise. In case the rover needs to turn right, Stratos stops the right motor and make the left motor turn clockwise.

STEP 4

Streaming the video and building the Android app will be the biggest challenges. Stratos Botsaris has a YouTube channel where he explains how the Spy Rover works in more detail (bit.ly/1n7qKOO). The final result is a seriously detailed spy tool that allows you to remotely monitor any location where you have a network connection.

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