SMaR: Day 6 Overheating Issues

header6The Sharp cable came in. And with the new acquisition of a wire stripper it was a piece of cake to solder on some female headers to the ends of the cables.
Ouch... Look at those clean stripped cables! Excellent!

I hooked the sharp up, stuck it on the servo and hooked up the robot to my laptop to finish the programming.

I entered the code for the motors first, the motors work.
I entered the code to debug the Sharp and *sniff sniff* that… does not smell good!
After a general inspection I found out that the L293D motordrive was really hot. I quickly disconnected the batteries and unplugged the motors, sharp and servo.
I took the L293D out of the projectboard and let it cool down.
Oh no, have I fried it? Have I fried any of the other parts? Oh no oh no!
I decided to work with an elimination method. So I hooked the board up to the batteries and intended to hook all the parts up one by one to check if anything was triggering this overheating.
After hooking up the batteries, the chip started overheating immediately.
Now I am not savvy enough to figure out for myself what this means. Does this mean the chip is faulty? Does it mean for some reason there’s too much power going into the board? Does it mean the board is faulty? I have literally no idea.

I decided to ask for help from the wonderful people at Let’s Make Robots!
After a bit of deducing I was asked to look at the pins I soldered into the board. Remember that picture of the first thing I soldered?
BAD SOLDER That turned out to be the culprit! Turns out: each pin needs to be soldered individually otherwise the whole thing circuits.
So after some re-soldering of the pins, I hooked everything up and hey presto! Everything works and the chip doesn’t overheat! Brilliant!

For now I’m leaving the robot alone, I will get down to the final programming tomorrow!


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