Building an Android Basic Programmable Tank for Less Than $50.00

The Smartphone based robot tank is s great project to build with your kids.  The project can be completed within an hour and requires no soldering or special tools.  When complete, simply download and install the EMGRobotics Audio Robot application on your phone.  The application will use the camera in your phone and various computer vision algorithms to roam around looking for a face or a specific color.  The robot can also follow a line or chase other robots around the room.  Currently only an Android application is available but an iPhone application is in the works.

Step 1: The RC Tank for This Project Can Be Purchased From Radio Shack

For this project we are going to modify this RC tank from Radio Shack into smartphone controlled robot.

Step 2: Build the Tank Per the Included Instruction

Use superglue on the shafts to keep them attached to the chassis of the tank. Make sure the wheels rotate freely after being installed.  Do not let the glue get into the gearbox.  While the glue is drying, rotate the wheels to make sure the glue does not bond the wheel to the chassis.  You want the wheel shafts bonded to the chassis, not the wheels themselves.

Step 3:

Cut the circuit board holders off the top of the chassis to make room for the new controller board.

Step 4:

Install the battery holder (per the instructions that came with the tank) and cut the motor and battery wires as shown.
Use the image below as a guide to determine wire length.

Step 5: Install the EMGRobotics ADMCB to Interface the DC Motors to the Smartphone

Strip the ends of the wires as shown.  Screw the wires into the green screw connector blocks on the EMGRobotics Audio Dual Motor Controller Board (ADMCB) as shown.  Be sure to note the color of the wire that goes into each side of each block.

Step 6: Drill a Hole in the Tank Top and Push the ADMCB Headphone Jack Through It

Install the tank top on the chassis, being carful not to yank on the ADMCB headphone cable.

Step 7: Modify Plastic "Over the Door Hook" to Mount Smartphone

Purchase a plastic over the door hanger.  Snap hanger in half.  Mount hanger (as shown) to tank using double sided tape.  Stick velcro (hooks) squares to vertical portion of plastic door hanger (as shown). Stick velcro (loops) to the back of your Android device.

Step 8: Download and Install Modified RFO BASIC From EMGRobotics Website

A version of RFO BASIC modified to control the tank is available from the EMGRobotics website.  Install RFO BASIC by clicking on this link: http://api.ning.com/files/mVad9iZi0UMX30h7MRtICPSKKAeoHaWt9tY8MmhEtN5-dbgO6ddlCGxquiFxGuNTubFORjHqnIaVc5-owabpTTCT1RXBWcWK/Basic.apk

After installing RFO BASIC, open it by clicking on the icon.

Step 9: Use the RFO BASIC "tone" Command to Control the Tank

tone <frequency> <duration>

Use the table pictured to control your robot using the tone command.

RFO BASIC supports

Graphics
Android Sensors (gyroscope, accelerometer, compass, GPS, ... )
Making calls
Receiving calls
Sending SMS messages
TCP/IP communications
In addition to many other features.

You can learn more about RFO BASIC for Android here: http://laughton.com/basic/

Step 10: You Can Also Control Your Robot Using Computer Vision

Using the free EMGRobotics computer vision Android Application (available on Google Play) you can have your robot tracking faces and tracking objects based on color.