DIY Arcade style Remote control car
If you have been reading my site, then you would have seen a post from my good friend Brandon over at zerosign.net. Anyway, Brandon posted a cool article today on a new remote control car called “Floor It!”. This is an interactive remote control car that reacts with the track that it is running on. It has sensors that sense special track obstacles, and responds accordingly. It has an oil spill that causes the car to spin out, water which slows the car down, power ups which gives the car a boost of energy, and a stop mat that makes the car stop. This car also has a nifty control mechanism. They have designed a free floating steering wheel that will cause the car to turn right if you turn the wheel right, and left if you turn it left. If you tilt the wheel away from you it will accelerate the car, and if you tilt the top of the wheel toward you , it will slow the car down. You can also view this video of the car in action, or you can read more about this car here.
My purpose in talking about this is that I want to discuss how a car like this works. If you follow the links you will see that this car is being produced for Mattel, so obviously the design secrets, are not going to be that readily available.
Something like this can not be that hard to design, and I don’t believe that it is. I am going to give a review of how I would design this car, and not how this car is designed, because I don’t know how they designed it.
Now to start out, we need to look at the steering wheel. This is not necessary, and you could just as easily use this car with a normal remote control, but if you insisted on replicating this, then I will tell you one way to do it. If you look at this wheel, it is basically a piece of foam or plastic cut into the shape of a steering wheel. The circuitry, as well as the transmitter has to be in the center of the wheel. This steering wheel could be designed using accelerometers. If you look at the mouse glove that I talked about, they are using accelerometers to function as a mouse. When they rotate their hand left or right, it causes the cursor to go left or right, and when they tilt their hand forward or backwards, it causes the cursor to go up or down. If you take these four outputs, and connect them to the appropriate inputs on the circuit board of the remote control, then you could basically cause this glove to control the car. You would rotate your hand left, and the car will go left, if you tilt your hand forward, then the car will go faster. Now you just put these components into a nice little package, and place it inside your rubber/foam/plastic steering wheel, and you have a nifty control for your model car.
Like I said, this steering wheel is not necessary to make your own Arcade Style RC car. You may ask yourself, then how does this car recognize these mats? Well, first it might be nice to review my Line Following Robot. I am using an infrared sensor to make the car detect black tape, or the white floor. On this robot, the light goes out of the emitter, and bounces off the floor, to be read by the sensor. I have the output of the sensor going into my micro as an analog input. I convert this analog input to a digital number using the onboard A/D processor. I did it very imprecisely by saying that black was anything below 1000 0000, and white was anything above 1000 0000, of course these are 8 bit binary numbers. I basically tested bit 7 to see if it was set or not. Now you see this gives me an easy way to detect white or black, and if those were the only two colors, then this would work. Now let’s suppose that I was only using a 2 bit A/D converter. Lets say that white would give me 11, green would give me 10, blue would give me 01, and black would give me 00.
This is over simplified, but is used as an example. If I wrote my software, and placed this on my little RC car, then as long as I had a 11, it meant that my car was on the white track. It would tell my car to carry on as normal. Now lets see what happens if my car ran over a green mat. The amount of reflected light would decrease, and my 2 bit A/D converter would now output a 10. I now have a state in my PIC program that says IF 10, then accelerate car for 5 seconds. After this 5 second burst of speed, and assuming I am reading white again, or 11, then resume to standard 11 velocity. My car has just gone over a power boost.
Now let’s assume that my car has gone over water, or a blue mat. My A/D converter would give me a 01, and I would have a subroutine that tells my car to slow down for 5 seconds. After my car has slowed down, and it is no longer on blue, then the car can return to normal state.
Now finally in my simple example, our car goes over black, which is oil, and the A/D converter gives 00. This will tell the car to turn all the way to the left, and give full throttle for 3 seconds. This will make the car spin out. After this, regardless of if it is still on the oil, it can resume normal control.
This means that our velocity and steering from our remote control have to go through the microcontroller. Normal white track state is obviously not maximum velocity, because you need some excess for the power boost. You also need to control the steering for the oil slick.
Anyway, This is just a quick discussion on how an algorithm could be built to control this car. A lot more work would need to be done to actually build the car, and there may be some better ways to do it, but this is the way that I came up with in the 5 minutes that I thought about it. Feel free to leave comments about it.
2 Responses to “DIY Arcade style Remote control car”
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Very cool. I just found your site and the DIY posts are great. Its a blast hacking around and building stuff by yourselft. Very nicely done.
Totally what innovation of that kind of car remote, i’ll take closer search of this site.