We recently purchased a rover from China that we controlled with an Arduino board and two MICILE tablets. The rover project was successful, so we decided to try again, but this time we are converting a remote control truck to a rover, a bit more accessible and a little less expensive option than the original rover we purchased. Not only is the RC truck cheaper, it seems to be a bit more robust as well. The MICILE tablet allows us many options when it comes to controlling to the rover, including an accelerometer (for steering and forward/backward motion) as well as the built-in camera (for sending back images of where the rover is). So, just as with our first rover project, we will use two MICILE tablets, one on the rover, one with the person controlling the rover. The MICILE tablet attached to the rover uses the built-in camera to capture video that is sent to the second MICILE tablet. The second MICILE tablet is used to control the rover. This is just part one of our project.
Our project consists of attaching an Arduino Uno board to the control board of the RC truck. We will use a dashboard app for the MICILE tablet to determine which wires control steering and which control movement forward and backward.
Step 1: Parts
Maisto Tech Rock Crawler - Green We bought it at Target, but it no longer seems to be available there.
Code to run the MICILE Dashboard app -
different colored wire
shrink tubing or electrical tape
Tools you will need:
a flux pen (not essential, but helpful for soldering)
Step 2: Take Apart the Maisto Tech Rock Crawler to Expose the Circuit Board
Take the top part of the Tech Rock Crawler off and open up the part that houses the circuit board. Your board should look like the board above.
Step 3: Load MICILE Arduino Uno Sketch App to Your Arduino Board.
The first thing you will have to do is load the MICILE_Arduino_Uno_Sketch app (available from the MICILE website) on the Aruduino board. Make sure your Arduino board is connected to your computer. Click on the "MICILE Arduino Uno Sketch" button and the .txt file will open. Copy the code. Open a new Arduino sketch, paste the code in, and press the "upload" button.
Step 4: Determine Which Wires Control Steering and Forward/backward Motion
Once you have access the circuit board on the RC truck, trace the wires from the motors that control the steering and the forward/back motors to the IC chips on the circuit board. We determined that the IC chips must be the H-Bridges which control the motors. The next step is to follow the traces on the circuit board (the metal parts that are slightly different color) back to their source from the H-bridge IC chips to the chip which receives the signals from the RC remote. When the RC remote activates any of the following items (steer left, steer right, forward, back) one of those traces should have 5V running through them for each function. You will solder wires to the signal input pins of the H-Bridge and activate each function on the RC remote. (We scanned the wires with an oscilloscope to detect which wires are going to 5V. The scope showed wires only going to 3.3V instead of 5V. This is OK since this is digital. Anything higher than 2V is considered "on" . ) You will then cut the traces on the circuit board (we did this by ripping out some resistors in the trace) so that the signal from the RC truck remote ic chip no longer reaches the h-bridges.
Step 5: Connect the Wires From the H-Bridge to the Arduino
Connect the wires on the RC circuit board to the Arduino Uno board.
Step 6: Important Note
The Arduino Uno outputs 5V, the RC car PCB expects 3.3V. We should insert a level converter between the two but since we don't have one right now, we will drive the RC car PCB with 5V signals. It should be ok for testing but probably not too good for long term use. We have ordered level 5V to 3.3V level converters from Sparkfun and they have arrived. When we update this project, we will solder it in.
The MICILE Dashboard app can be used to tell which wire controls turning left, turning right, moving forward and moving backward. The MICILE Dashboard app has a user interface that allows you to press a button that activates a pin on the Arduino board which then activates the RC truck circuit board. Use the MICILE Arduino Dashboard App to turn the pins of the Arduino on and off to test each function. Warning! If you turn on both steer left and steer right at the same time you will cause a short circuit in the H-Bridge and probably blow it up. The same goes with trying to go forwards and backwards at the same time.
We will publish the final project with pictures and complete video soon!