This week and last we focused on building and programming the NXT robots to do simple tasks and knowledge of radius, diameter and circumference to calculate how far they traveled in centimeters.
The initial building of the robots proved to be somewhat frustrating for me because of the number of small parts involved, but after some initial difficultly finding the right sized pieces I got it up and running. Our first task was to make them go forward, back, and stop at varying speeds through the controls, as well as download the programs into the robots so they could move independently of the USB cables. We also had the option to program them to either play notes or a song, and program the duration of each individual command. We could also change the speed at which each individual wheel rotated, allowing them to go in a circle.
Though interesting, I found the computer interface to be somewhat hard to use and had to ask for assistance several times, and when I did get it working it didn’t always go as planned. More than once I thought my robot would only go forward a very short distance but wound up chasing it across the room until it either stopped or I picked it up, and I’m not sure I completely understood that aspect of the program. I also barely managed to catch my robot at one point because it overshot the edge of the desk, but aside from some minor repair work on the front wheel it was fine.
Later, when our task was to calculate the distance traveled by the wheels based on the diameter and simple math to determine the circumference. My calculations proved to be very close to the actual distance it traveled, though off by a few fractions of a centimeter. This was most likely due to human error or related to the surface the NXT was on.
After playing with the robots for a while Mr. Vale gave a presentation on several types of simple motors, most of which have been around for over a century. The Sterling Engine was first invented in 1816 as a substitute for the steam engine, and works due to a temperature differential of 30 degrees between the air and the water below that causes the fan to spin. This type of engine is used to pump water in areas that do not have electricity, and have a 40% efficiency.
A Peltier Device works using two dissimilar metals where one side is heated and the other is cooled, creating electricity at the junction. These devices are commonly used to cool drinks or make fans that cool the insides of computers.
A BiC lighter uses a small piece of quartz inside to create a spark using the piezoelectric effect, which is the result of pressure applied to the quartz. This technology has been around since 1880, and is most commonly used in lighters and in lighters for gas stoves.
Finally, a Mondiccino motor is a small motor that uses magnets that cause the center shaft to float and light to generate a charge from several solar cells on the shaft. While cool to look at it does not have much practical application, but is frequently made by hobbyists from kits, including ones Mr. Vale sells.