Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: vishalsaxena on June 06, 2008, 10:09:25 PM

Title: Problem in $50 robot MCU
Post by: vishalsaxena on June 06, 2008, 10:09:25 PM

Here is my MCU please help........... When I connect my battery to The 3 battery pins
I dunt get my LED giving out light but when I connect it directly from the back of the board I see the light Is something wrong with my soldering...........

Rest Im getting around 6.13 volts at my servo bus and about 5.00 at my sensor bus........

Please solve the problem.

Ive attached the back view of my board as a jpeg file in this post...... :D

Thanx
Vishal Saxena

Title: Re: Problem in $50 robot MCU
Post by: bens on June 06, 2008, 10:48:58 PM

You've used way too much solder.

Title: Re: Problem in $50 robot MCU
Post by: vishalsaxena on June 06, 2008, 11:18:50 PM

Does it make any difference?????????????

Title: Re: Problem in $50 robot MCU
Post by: bens on June 07, 2008, 12:33:53 AM

Yes, it's almost certainly the cause of your problems.  You probably have a number of shorts.  Additionally, using too much solder can result in bad connections between the solder and the wire.  Your solder joints should ideally look like the ones on the through-hole pins below:

(http://www.pololu.com/picture/thumbnail/0J662.jpg?size=600)

- Ben

Title: Re: Problem in $50 robot MCU
Post by: paulstreats on June 07, 2008, 03:23:21 AM

Though BENS is correct in what hes saying, you may not have a problem at all. The led is only supposed to light up when the atmega8 has been programmed.(have you done this yet?).

The fact that you are picking up the correct volages at the correct buses indicates that you dont have any shorts anywhere.

Title: Re: Problem in $50 robot MCU
Post by: bens on June 07, 2008, 03:47:18 AM

I should note that I didn't actually read the opening post and I have no familiarity with the particular system you are trying to build.  Seeing the word "problem" and a picture of that solder job leads me to have the default response of "solder it better and then debug it" (or at least use a multimeter to do some continuity checks on places that look like they might be accidentally shorted).  Plus I feel like I can see several shorts already in the picture, though I'd need a better picture or a different perspective to be sure.

- Ben

Title: Re: Problem in $50 robot MCU
Post by: vishalsaxena on June 08, 2008, 10:18:47 AM

Thank you very much people.....specially paulstreets and bens Yeah
I didnt programmed the ATmega 8.........
I couldnt fing a cheap Programming cable anywhere...........I thought of making it myself........
and burnt my hand by solder........ :-[  I tried to solder 10 pin IDC to 9 pin female serial directly.........How stupid..........  :D       

Ny body got any Idea how to...........make a cheap programmer????

THANK YOU EVERYONE FOR UR SUPPORT
VISHAL SAXENA

Title: Re: Problem in $50 robot MCU
Post by: vishalsaxena on June 08, 2008, 10:25:10 AM

WELL  how do you do such a perfect soldering?????????


Although it was my first soldering experiment and used wires that had multiple Al wires inside
So my board kinda got messy...........Nd I got burns several times.... 
In delhi(INDIA) I was only able to find PCBs like the picture Ive attached In first post of this "SUBJECT" 

thank you
Vishal

Title: Re: Problem in $50 robot MCU
Post by: pomprocker on June 08, 2008, 11:12:30 PM

check instructables.com for a "ghetto avr programmer"