MeasuringBot incorporating littleBits cloud module
The Challenge: Design a MeasuringBot that can measure a linear distance.
The concept of the MeasuringBot is an integrated Math-Design-Engineering Challenge for 3rd Grade and up. Under 5th grade would not be expected to apply 2πr=C in their methodologies, but advanced 5th graders and higher would. In the following example, students would also test the effect of differently sized wheels on the measure linear distance. Based on this, they would be asked to predict how many 3 second motor impulses would be required to travel a specific distance.
These concepts apply directly to robotic planetary exploration such as the Mars Rovers. Since "rover drivers" can't see the rovers move, they must employ other indirect methods of knowing where the rover is. Motor rotation rates and wheel sizes are known quantities. Knowing how long the driver motors were engaged allows one to calculate the distance traveled and prevent driving into a hazard.
In this prototype, a wheel with a radius of 2 cm was chosen. The pulse rate from the Cloud Module is 3 sec. yielding 1.5 revolutions. 1.5 • (2 • 3.14 • 2) = 6.28 cm of travel per pulse, or about 15.9 pulses per meter of travel.