Remote Control Jeep Community Service Project – Part 3

This is a continuation from part 2. If you haven’t read it yet you can here.

I was almost done. All I had to do was figure out how to combine the two programs together so that I could receive data from the controller and then send it to the motor controller.

Combining the two separate programs was difficult enough, but after a little bit of time and a lot of trial and error, I had it working (sort of). Next, I had to figure out how to convert data from the xbox controller to the motor controller. The problem was, the data I would receive from the xbox controller was going to be a number between -32767 and 32767. But, as I said in the last part, the motor controller only receives a pulse delay of 1000-2000. So, I had to create an algorithm to convert the numbers from the xbox controller to the motor controller. To do this, I did a lot of math.

I won’t go into detail about how I figured out the algorithm, but it did take awhile. Eventually, however, I did come up with an algorithm that worked: (Power/65.5) + 1500 = PWM signal. (Where power is the number from the xbox controller.)

Finally, I had a program that would receive data from the xbox controller and then convert it and send it to the motor controller. But I wasn’t out of the woods yet. The first problem came while I was still trying to figure out what algorithm would work. I discovered while I was testing that if the xbox controller lost connection with the Arduino while the motors were running, they would keep running at the speed and in the direction the xbox controller had determined before it lost connection. What this meant is that if you drove the jeep too far away and lost connection with it, it would just keep driving until you either ran up to it and switched it off, or regained connection with it and stopped it. Obviously, that was not a good thing, but I was able to fix it fairly easily with a few lines of code.

The second problem was more difficult. I had turned in the Jeep and thought that I was done with it. But then, I received word of a new problem that needed to be fixed. When the jeep was put in full speed forward from being stopped, the front end would lift up into the air for a few moments from the sudden increase in speed. Even with weights added to the front it would still do this. Obviously, this was not safe in the least for a child, and so it had to be fixed. Originally, I thought this was going to be easy, but I quickly realized that it was going to be more difficult than I had thought.

Continue reading in part 4 here.