In my meeting, I discussed with my Mentor what the final result of my car will be. I decided that a good milestone is getting my car to drive around an elliptical track. The next step will be to add obstacles to the track and make the car drive around them. To get this all to work, I will use all three of my sensors. I will mount my ultrasonic sensor on a servo and pan roughly 135 degrees to get an image of the car's surroundings. Using math to avoid scraping the side of the car on a wall, I will have the car go towards the furthest away point. I still have to test my sensor, but hopefully it will be reliable enough that I don't have to worry about noise in my measurements. My two IR sensors will be located on either side of the car to help it know how close it is to a wall, in the event my math is off.
|Motor driver in breadboard|
|Protoshield on top of Arduino|
I have a hard time describing how the steering works, so I figure I'll just attach a little video I (thankfully) took before I had completely disassembled the car. As the video shows, the motor turns the wheel which pushes the shaft left or right. The arms, connected by a spring, bring the shaft back to center after it's done steering. The complications that arise from this are that I do not know what the motor was doing while I continued to tell the wheels to turn; it was either moving or stopped, and there is a difference between the two. If I keep the motor running, to counteract the force of the spring, the motor makes an annoying sound which is evidence of it becoming damaged. I took out the spring to eliminate the sound, but with no spring there is nothing to push the wheels back to being straight. In order to figure out what I need to do, I'm going to have to take a closer look at how that motor is supposed to be operated by connecting it back to the RC board.
But I was able to get the rear wheels, the drive wheels, working properly. So I have left out steering for now, but I have gotten the car working. It is fully autonomous, driving without human input. I have a video below as proof of my eighth wonder. You can see in the video that the car is running off of a 9V battery; this is because the car's rechargeable battery is out of power.
Also seen in the video are various pieces of masking tape. Right now, it is the only thing holding my Arduino to my car; a future project will be to find a good way to mount the computer to the car. Also in that vein, I will need to mount my sensors and servo to my car, but I'll solve that issue when I come to it.
Here's the video, the fruits of this past month of labor. 'Til next time, Enjoy!