Hello again!
Apologies for the lack of updates in the last few weeks! Work has been piling up and unfortunately not a whole lot of was done in terms of robot building. Lots of ideas were being thrown around here at C.A.K.E HQ. Gian came up with an amazing looking idea for the body and chassis of the fight bot and I must admit I’m very impressed. Looks spectacular and cant wait to get it built!
The overall design our robot is going to incorporate the use of two Sharp IR rangefinders to act as a means of locating the opponent during a bout. The idea is to use two sensors with their beans crossed. If one beam is broken by the presence an opponent’s robot, our robot can be turned in a particular direction and stay turning until the next beam is broken thereby leaving our robot facing head on towards the opponent. This picture gives an idea of how the sensors could be positioned.
The sensors work off a 5v supply with a varying voltage out depending on the distance that the object obstructing the infra red beam is from the sensor. I carried out a small experiment in class today to see the response of the sensor with various materials to see if different surfaces affect the output of the sensors differently. This graphs plots the response of the sensor.
The graph shows the response of the sensor using a paper and metal surface. There is a few small variations in some points in the graph but both surface led to similar results with the trend following what was expected. These results will give an idea of what to threshold to set in the code depending on the design we end up using on the robot.
Gian managed to source a new set of motors that are about the size of a AAA battery!!! That’s including the motor and gearbox. Very neat indeed. The main issue that arose with using these motors though was the fact that the diameter of the shaft is no more than 1.5mm and finding wheels with a matching diameter in the centre is very hard indeed. Since the wheels we plan on using have a 4mm hole an adapter is going to have to be fabricated before the motors can be attached to the wheels. While discussing how to manufacture a metal adapter in class today, the combination of Gian and I pulling apart Chris’ pen(which he left in one of the wheels) in boredom led to the discovery of a free, pre made, perfect fitting adapter in the form of the nib of a pen and the inner tube in which the ink is kept. Eureka! By cutting the tube short and inserting into the middle of the wheel a convenient hole is left for the motor. Along with a drop of super glue and some epoxy cement, the wheels can be attached. JOB DONE!
Here is a few pics of the the motor and and the part of the pen we plan on using as an adapter,
Took a quick video of the driver powering all four motors, apologies for the poor quality. Chris should have a better video up pretty soon,
Until next time,
G’luck!
paulleamy 