Here’s the first project I’m working on publicly. I’ve recently dissected an R/C car with my 9.1 megapixel point-and-shoot in hand. Also related, I’ve never used Flickr before. However, I decided that posting a bunch of pictures on this one page would be bulky and annoying, so I figured it out for you.
Here you are: http://www.flickr.com/photos/jorhlok/sets/72157629069649186/
Feel free to look at all the pictures now, wait until you’ve read the below, or follow along.
Okay, first two pictures, we have front and back shots of the car before I begin. It’s about a foot tall, has big squishy tires, and a basic suspension system. I bought it at the local flea market for $5. It had no battery or remote controller. The important bit is the motors.
After I took those pictures I wildly unscrewed all screws in sight! lol. Well, if you want the truth, I unscrewed the front bumper, then the back bumper, and finally the main body. Now we have the most important part uncovered: the structure of the chassis and the leads to the motors. In the background you can see the removed bits. Also in the background is the tissue box I put the screws and other assorted bits in.
The next two pictures show off the suspension. It has about a centimeter of clearance. It’s not much, but it’s fine for a $5 foot-high car.
The next picture shows the bottom of the PCB. It’s a single sided PCB populated entirely by through-hole components. It’s a wealth of parts for an electronics hobbyist. The IC is labeled SUPER CHIP! Anyways, I can infer that the car is pretty old. Possibly from the last millenium. Any remotely modern R/C car would have one of those IC processors bonded directly to the PCB and covered with a blob of black epoxy. It’s called “Chip-On-Board” and it looks like this: http://i00.i.aliimg.com/img/pb/457/973/388/388973457_338.jpg
The next picture shows the PCB removed. I also attempted to desolder the connector, but accidentally pulled out a few pins. The next picture shows that I was able to stick them back in. However, the female part of the connector readily accepts solid core wire, so I probably won’t use the connector.
The next picture is a closeup of the chassis without the PCB in it. I also stuck the male connector in there.
The next two are videos of me testing the motors with a 9V battery. The steering is a 3 position system that’s just left, center, or right. I’m pretty sure it’s just a DC motor in there, despite the complicated connector. I only got 2 wires to do anything for me. Also, it’s not shown, but I got the drive motor hooked up enough to the battery that I was able to set it down and it drove across the carpet just fine. When it slammed into the door, it dislodged the precarious connection I made. So I know the motor runs reasonably well with 9 Volts. Inside the battery compartment, it says “6.0V POWER PACK.”
Now that all this potential has been laid bare before me, there’s no telling what I can do! </ego> lol
Oh, except that I’m going to tell you. The last picture shows an Arduino Uno fit snugly into the battery case. That should give you a hint. Also, I reattached the front bumper because it holds the front suspension in line with the rest of the chassis.
I’m currently in the process of shopping on SparkFun for parts, including two lovely XBee radios. That’s right, I’m going to build my own R/C for this car. Before I get them in, I’m going to hook up my Arduino and a motor controller board in the car and control it with a Wii Nunchuck. I got a “Wiichuck” Nunchuck connector/breakout from SeeedStudio and will use it for the prototype. Then all I have to do is hook up the radio system, build the remote, and I have my finished car. I set a budget for $175 (including ~$13 shipping) for the parts I need for this, one other project, and a few miscellaneous parts I’d like to play with (I rounded the budget up). As a hint, the other project has made a cameo in the picture set.
EDIT: This is very similar to what I’m doing: http://arduino.cc/blog/2010/03/05/wireless-robotics-platform-cheap-rc-vehicle-arduino-xbee-processing/
Also a link to the original page: http://nootropicdesign.com/projectlab/2010/03/04/wireless-robotics-platform/