This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida (www.makecourse.com)
Step 1: Control System
This truck is controlled by an Arduino Uno using a Bluetooth module. The Android app that I used is called Arduino Joystick Controller, and is available for free on the Play Store. (Arduino Joystick Controller) I used an L298 motor controller to control the speed of the DC motor for the rear wheels. Steering is controlled by a small servo motor. I also added led headlights and taillights to show when the truck is turned on.
Step 2: Components
Mock up the wiring to figure out how everything works before trying to fit it all inside the truck. Once everything is working properly, simplify it as much as possible so that it can fit inside the body of the truck. I had to completely rewire everything 3 times before it would finally fit inside.
Here are the components used:
L298 motor controller
DC motor (found in my box of random stuff)
SG90 micro servo
HC-06 bluetooth module
9.6V rechargeable battery (from another R/C truck)
Step 3: Programming
Here is the code that I used for my truck. I added comments to the code to explain the function of each section. If you would like a better understanding of how the Android app communicates with the Arduino, this website does a good job of explaining that in depth: 6.Joystick Control
Step 4: 3D Modeling & Printing
I modeled the entire truck in Solidworks, and 3D printed all of the pieces except a few shafts and gears that I found in a toy set. The steering assembly is a rack and pinion setup that was 3d printed. I separated the body into multiple pieces to make it easier to print and also easier to work on. There were over 25 different printed parts in the entire assembly.
Step 5: Assembly & Finished Product
I assembled the truck using fasteners from the same toy set that I took the gears from. If all else fails, hot glue works well for attaching some of the non-structural components. It also may be necessary to use a dremel to trim some of the pieces if they do not fit together quite right. DON'T LEAVE 3D PRINTED PARTS IN YOUR CAR. I made this mistake, and had to reprint several parts because they had melted in the heat. In the end, this project turned out well. Here is the final result: Bluetooth R/C Truck