Review Of The Presentation Day

After having to undergo last minute alterations to our buggy design and code, we we're in a decent position for the presentation on Tuesday afternoon. On our first trial of the test track Dr Thompson put together, the buggy seemed to make good progress - only to lose its way on the third corner of the track. After frantic attempts to re enter LDR values into our code, we eventually were forced to bow out. We then tried our hand at the two symbols. Needless to say the buggy didnt fair extremely well on these, but it gave valiant effort on the T-Junction exercise where it did stop, but failed to reverse. The buggy also turned the opposing way on the L symbol. Although the performance was disappointing, our buggy was among the relative 'high performers' on the day and hopefully the marks will be adjusted in a standardised fashion taking this into consideration.

Ive compiled a few reasons why maybe things didn't go to plan on the day of the presentation:

1. The Track-

It was made of cardboard of an off-white colour and some sort of thick belt like material put in place to act as a 'black line'. Our buggy simply wasn't able to follow this line effectively due to mechanical constraints of our front wheel/ ball bearing, and having tested the buggy on normal white paper with a seamless printed black line on this, it was always going to be a difficult task.

2. The Light-

The room lighting also affected the operation of the buggy, in particular the LDR's that are obviously crucial to the working capabilities of the buggy. My group actually calibrated the LDR's in a room that was no where near as bright as room 160 and in hindsight maybe should have taken this into consideration. We set binary values of 90 for both LDR's so that once reaching a value higher than this (i.e light levels were low) either the left or right motor would stop, bringing the buggy back on line with the black line. When we were in room 160 and went onto picaxe to re-calibrate, we were getting readings of 40 off of the black line, and only 75 on it, meaning that whilst conducting the trial, neither motor was receiving the 'stop signals' because the values we had were too high for that particular lighting in the room. We did attempt to turn the lights off in the room but consequently found out that room 160 is motion sensor -responsive, therefore making it impossible to turn the lights off.

3. The LDRs!!!

The LDRs themselves were not of the best quality and because of their sensitivity we had to keep changing the values of the program. In theory the program was perfect, but we just couldn't get it to perform in practise on the day, although we have video evidence of it working on our own track.

Feedback on the task as a whole:

The group worked well together and after many meetings managed to put together a good buggy design. We delegated tasks effectively and tried to share workload evenly, although naturally those who had more experience in the electronics area (Onwell & Raj) shone through and really took the buggy to a competitive level by providing direction in times of uncertainty so a big thanks to those two. As for improvements I would say that we probably should have used an extra LDR because of the accuracy benefits it brings. Instead of using two where effectively the LDR has to wait until it has come off the black line to start again and sort of over correcred itself and had to come back a number of times, the third LDR would act as an 'adjudicator' so if the buggy was going to over correct itself, this would stop the over correction and normal service would continue.