On the one hand, we could delve into XBEE, or possibly in the near future use other tools like BLEduino or Flutter. But I'm not sure if I can spend that much time on the wireless control and programming when there are other aspects to their projects that students want/need to explore. There is a lot of prototyping to do, and integration of Arduino for some, and I want to make sure they get that exposure and time. For this stage, the prototyping and simple programming is more relevant.
Therefore, on the other hand, we could simply hack an RC and use its parts. I sent out an all-points bulletin to my faculty today to see if there are any folks who have old toys, like remote control cars and boats, that they wouldn't mind donating to the class. I will ask the parent body later today.
In the meantime, I purchased a very cheap ($14) RC Car from Radio Shack, and will hunt down all Goodwills and Salvation Armies in my neighborhood in the coming days. I tested out this cheap toy to make sure all was in working order, then took it apart with the students.
Guiding questions prior to opening up the toy:
- "What's going on inside the transmitter, what do you think it's doing?"
- "What's going on inside the car? What makes it react the way that it does?
- "Which components, that we've already learned about in class, do you think are inside?"
- "Since we know there must be motors, what kind are they, and how many are there?"
It was a really good conversation as students hypothesized what's inside and how things worked. We all guessed, incorrectly, that there would be a servo motor controlling the steering in the front. As it turns out, there's a clever way of using a standard cheap hobby motor to steer instead. The hobby motor at the front has a plastic piece that acts like a steering column. Turn the motor one way, car goes left, turn the other way, it goes right. You will see it in the photos below. Servo motors are relatively expensive, so hobby motors make more sense.
Finally, we discussed how we can take a car that does forward/reverse and left/right, and repurpose the technology in our projects. For example, an RC boat may use the steering as a rudder and the other motor can propel. A helicopter, if engineered lightly enough, might use the motors to get up in the air. There are many possibilities.
For more information on RC Cars, see this article from How Stuff Works.