Two steps forward, one step back, another forward and then one back...

Can you see the error?

I'll start with the good news, I have now received all of the required components to build all the modules and have been constructing them when I have spare time.

I began to solder the Edgebot boards as soon as the parts started to arrived, and that process was completed without any hiccups, moreover when the quick build was finished I was able to test it using a few LEDs on the outputs, a switch acting as an the input and a small power supply, this enabled me to thoroughly test the Edgebot circuit and it appeared to function correctly.

When the components finished arriving I was also able to finish the Photovore, again without a problem, however I was then naive and reasoned that because it had few components and that I have worked with simple comparators before, that that board would work, more on that later.

Before I soldered each board I quickly looked over the tracks and layout again (having also done so when receiving them) and this time I noticed a fault with the motor controller;

Can you see it now? It is the short connecting all the pins.

This could be resolved relatively quickly using a lot a light, some magnification glasses, a scalpel and a steady hand. I made a shallow incision into the connecting track and then I was able to carefully peel back the track and sever it at the next pad, this completely removed the connection, this is easily seen with the track leading to the centre pin of the voltage regulator in the following image;

It isn't neat, but it gets the job done

I have since been able to solder the motor controller board completely and thoroughly test it both with and without motors, it seems that my worries about the L293D were unnecessary; it functions fine with a 6 volt input voltage (4x AA) and it also produces less heat than anticipated thus meaning there is no need for a heat-sink or other cooling method. Here are images of the (working) boards;

The fully soldered Edgebot module

The motor controller, without the confusion of the voltage regulator

Once the first chassis design has been finalised, a video of the robot shall be posted, this should be shortly.