### Author Topic: \$50 Robot Circuit Problem  (Read 739 times)

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#### kser

• Beginner
• Posts: 2
##### \$50 Robot Circuit Problem
« on: July 24, 2010, 12:08:50 AM »
Hello, so I recently finished soldering and hooking up my circuit by following the \$50 Robot instructions. This is my first ever time to do such and so I'm a total noob and so I'm not too sure how to test and make sure everything is connected properly. Due to this, I went with the plug, pray, and hope....sparks flew and I was wondering if someone could help me solve where I might of messed up.

So question is: What would cause the wire between the 5V Regulator and the three pin header to make a spark and burn the wire? Because mine did that and I don't know what I did wrong. Any specific spots I might of messed up the soldering or something? Does it matter if the solder on the 5V regulator is touching both the ground and power because both solder bubbles kind of merged together?

Thanks so much for any help!

#### voyager2

• Supreme Robot
• Posts: 459
• Behold! The Impossible Triangle of robotics!
##### Re: \$50 Robot Circuit Problem
« Reply #1 on: July 24, 2010, 01:28:03 AM »
Hi,

Does it matter if the solder on the 5V regulator is touching both the ground and power because both solder bubbles kind of merged together?
You bet it does!
That would create a short and possibly fry the regulator and micro-controller.
Please tell me you didn't have the ATmega plugged in...

Voyager2
And Admin said "Let there be robots!"
And it was good.

#### billhowl

• Supreme Robot
• Posts: 375
##### Re: \$50 Robot Circuit Problem
« Reply #2 on: July 24, 2010, 01:43:50 AM »
pictures tell a thousand words, Please show us some pictures of what have you done, preferably in high resolution.

#### Soeren

• Supreme Robot
• Posts: 4,672
##### Re: \$50 Robot Circuit Problem
« Reply #3 on: July 24, 2010, 09:36:10 PM »
Hi,

Does it matter if the solder on the 5V regulator is touching both the ground and power because both solder bubbles kind of merged together?
You bet it does!
That would create a short and possibly fry the regulator and micro-controller.
Please tell me you didn't have the ATmega plugged in...
Nothing would get fried except perhaps the power source and the wiring/traces involved.
It's a dead short, so no power will get to the controller (or the regulator, but it may have been killed while building up the solder bridge).

kser <- I am a bit shaken, that anyone could ask such a question! Did you think that schematics and such were just made as a suggestion/recommendation that could be followed or not - what you did was the same as shorting your battery (or PSU) with a screwdriver.
We have all made short circuits at some time... But asking if it matters

The number one source of errors for beginners is poor soldering, find an old/discarded piece of PCB, study how the solder joints looks and practice removing the solder and resolder until you are through "blobbing" and start making good joints.
Next thing, get a magnifying lens and examine your work carefully a couple of times under lots of light.

You need...
1 Solder Sucker
1 Reel of Desoldering Braid
1 Magnifying Lens (x4 to x10)
1 cup of patience
2 ounces of determinism
1 Aloe Vera plant (for when you splatter solder on your skin)

Stir under medium heat (~700-800°F) if using leaded solder, a bit higher if you use the unleaded variety.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Engineering is based on numbers - not adjectives

#### kser

• Beginner
• Posts: 2
##### Re: \$50 Robot Circuit Problem
« Reply #4 on: July 25, 2010, 10:28:01 PM »
thanks voyager, i did not have the atmega plugged in because, like I said, I was unsure of my soldering skills, so luckily I didn't.

and soeren, no I did not "think that schematics and such were just made as a suggestion/recommendation", I'm new to this, not stupid. I was just trying to throw out some possible reasons, I soldered the best I could but as I said, it was my first go around. thanks to yours and voyagers post I will double check to see if soldering was the problem. that magnifying glass is a good idea, I'll need that closer look to see if any two solders attached.

appreciate the help, if it's not the soldering like was suggested, I'll check back with yall

#### voyager2

• Supreme Robot
• Posts: 459