Author Topic: $50 robot electronics help (Read 5580 times)

the jeenyus · « **on:** March 10, 2009, 03:30:28 PM »

hi i have been working on the electronics part of the $50 robot for a while, trying to get it to work, and it doesnt work lol.... i think my problem is the voltage regulator did not have any output so i replaced it, but it still did not work after that. i was hoping i could get some help please? i bought the regulators from radioschack and not digikey by the way i dont know if that had anything to do with it. i will send pics if need be but i followed the directions excatly.

frodo · « **Reply #1 on:** March 10, 2009, 03:41:36 PM »

Quote from: the jeenyus on March 10, 2009, 03:30:28 PM

but i followed the directions excatly.

Are you sure you didn't put the voltage regulator in the wrong way round?

Soeren · « **Reply #2 on:** March 10, 2009, 04:55:04 PM »

Hi,

Quote from: the jeenyus on March 10, 2009, 03:30:28 PM

[...] so i replaced it, [...]

With what part?
What's your input voltage?
Did you measure the output of the regulator or how did you determine that it was dead?

the jeenyus · « **Reply #3 on:** March 10, 2009, 05:04:17 PM »

I am pretty sure the regulator has the right orientation, I followed the schematic, but there is still a possibility that something else could be wrong. The section of the circuit that is dedicated to the servos works, but there is no output voltage for the regulator, and I get the feeling that there probably should be. I replaced the regulator with the same exact part, purchased at Radioschack, a 5v output regulator. I posted these pictures for clarification. Please tell me if you see anything else. Please help me!!!

frodo · « **Reply #4 on:** March 10, 2009, 05:11:29 PM »

i can't actually see the images so i'm stuck there but there is definately supposed to be some output voltage which could be missing if the voltage regulator has a fault inside it or there is a mistaken connention on the circuit somewhere.

the jeenyus · « **Reply #5 on:** March 10, 2009, 05:19:29 PM »

If i could have help on posting pictures please...

the help on posting didnt help.... Im really haveing trouble with directions arent I?

frodo · « **Reply #6 on:** March 10, 2009, 05:21:39 PM »

are the pictures posted on the internet at a website ie. photobucket?

the jeenyus · « **Reply #7 on:** March 10, 2009, 05:24:26 PM »

I cant figure out how to post pictures not online but from a digital camera. Please tell me how to post them! Please?

SmAsH · « **Reply #8 on:** March 10, 2009, 11:21:27 PM »

Quote from: the jeenyus on March 10, 2009, 05:24:26 PM

I cant figure out how to post pictures not online but from a digital camera. Please tell me how to post them! Please?

so down the bottom of the page there is a button labelled "additional options" click it. browse for your photo, also make sure the format is a working one! if it is not open it with paint and change it to a jpeg. note: it must be under 500kb.

dellagd · « **Reply #9 on:** March 11, 2009, 06:36:39 AM »

do some continuity tests to make sure all of your soldering is good, and yes, check to see if there is 5v coming out of the regulator.

the jeenyus · « **Reply #10 on:** March 11, 2009, 06:34:28 PM »

Ok here are my pics. Please tell me if you see anything. It is not done in this picture, but I cleaned off the stray flux on the board, but the output still does not work. Could I possibly have a wrong or faulty part? Btw Output is definitely not touching ground, it may look like it in the photo but it was carefully cleaned and tested, doesnt work.

My method of finding out weather or not it works was by using a spare LED to see if there is anything going through. It lit up for the servo pins but not the sensor pins... I will invest in proper testing equipment soon but for now a poor man must use what he must. lol

the jeenyus · « **Reply #11 on:** March 12, 2009, 03:45:35 PM »

Also, I have read other posts that the LED does not light up until you program the microcontroller, but I attempted to program it, while power was on, and it still did not work. Should I just buy new components and make the board all over again? Could there be faulty parts? Did I use a wrong part?

dellagd · « **Reply #12 on:** March 12, 2009, 07:06:24 PM »

I wouldn't scrap the board until you are absolutely sure you did everything correctly.
did you do those continuity tests?

P.S. could you take pics of the board's soldering from different angles?

the jeenyus · « **Reply #13 on:** March 12, 2009, 08:17:16 PM »

Ok here's a couple different angles. I'm pretty sure its not my soldering though, at least I hope. Nothing seems to be touching unless its really really really small. I am not exactly clear on how to properly test it, because I do not know what equipment to get, or where (maybe from Radioschack?) Please give me advice... But anyway here's the other pics.

SmAsH · « **Reply #14 on:** March 13, 2009, 12:55:28 AM »

to test it go down to radio shack and pick up a multimeter. then test your traces by putting one led on one part and another lead on another part and see if theyre touching. just make sure everything that is supposed to be touching is and everything that isnt isnt!

dellagd · « **Reply #15 on:** March 13, 2009, 06:06:46 AM »

hey, I think I got it.

don't these 2 need to be touching?
that is the power supply for the programmer and they don't seem to be bridged.

can someone confirm this?

SmAsH · « **Reply #16 on:** March 13, 2009, 06:14:05 AM »

that bottom one looks like its connected to the +5V power bus dont know what the other one is though. just a question, are you going to connect the other leg of the led to a resistor?

dellagd · « **Reply #17 on:** March 13, 2009, 06:20:41 AM »

to me it looks like there is no solder in between the two pins I am pointing to.

PS smash are you talking about my post?
If the answer is yes, I would add some more solder between the 2.

PPS like smash said, are you going to connect the other leg of the LED to a resistor?
it doesn't look like it to me.

SmAsH · « **Reply #18 on:** March 13, 2009, 06:27:19 AM »

sure am! and take a look at this http://www.societyofrobots.com/images/sbs_avr_schematic.png it may help i think the top one is connected to vcc and the bottom is mosi??? well im pooped, i cant really tell tbh. wait for a pro to come confirm this. in the mean time take a look at these for some help.
http://www.societyofrobots.com/images/sbs_avr_schematic.png programmer outs.
http://www.societyofrobots.com/images/sbs_connect5_large.JPG large pic of what you want.
http://www.societyofrobots.com/images/sbs_connect7_large.JPG nother large pic of what you want.

the jeenyus · « **Reply #19 on:** March 13, 2009, 01:37:15 PM »

What do you mean about the resistor on the other leg of the LED? I soldered a 340 ohm resistor to the LED onto the board like it said in the schematic, in the orientation it said in the schematic. It says to connect the resistor to the cathode end of the LED and to the signal pin or something for the servos... i think. I am not exactly sure what you mean. I am such a beginner lol.

Concerning the soldering of the programmer pins to the power bus, in an earlier post a clearer picture shows a better view of the connection. Is it wrong?

dellagd · « **Reply #20 on:** March 13, 2009, 01:52:37 PM »

the first pic is your board, and the second pic is Admin's board.
I am pretty sure the admin is correct.

I am pointing to the same pins on each board.

on yours, it looks like the pins are not soldered together
on Admins, it looks like they are.

once again, can someone confirm this.

SmAsH · « **Reply #21 on:** March 13, 2009, 02:39:16 PM »

yeap admins pins do look mighty bridged.

the jeenyus · « **Reply #22 on:** March 13, 2009, 06:20:04 PM »

Ok I will check those connections and re-solder them. Thank you for your help, and hopefully continual support, as I am sure I am not done with this post yet...

SmAsH · « **Reply #23 on:** March 13, 2009, 06:37:11 PM »

we'll always be here to help

dellagd · « **Reply #24 on:** March 14, 2009, 05:51:17 AM »

report back telling if that was the fix

the jeenyus · « **Reply #25 on:** March 14, 2009, 02:38:25 PM »

Ok I re soldered that connection and included a pic, and I got a multimeter and tested the circuit, and it read about 2V for the section where the servos are supposed to go, and about 11mV for what is supposed to be the +5V power bus.

Does this mean that the problem could possibly be my batteries or the capacitor? Or could the voltage regulator be the wrong part, or is there supposed to be more input into the regulator to get a significant output from it, or something like that? My capacitor is in the right orientation, and 220mF. I included a pic of my batteries because maybe I made a noobish mistake on buying batteries... lol. Please help

the jeenyus · « **Reply #26 on:** March 16, 2009, 04:29:31 PM »

By the way my batteries are 6V 1400mAH. The batteries used in the tutorial are 6V 1800mAH. I dont know if that is the problem, because I am not an expert on batteries, or know what mAH means. lol please respond and help.

dellagd · « **Reply #27 on:** March 16, 2009, 04:39:13 PM »

maH means milliamp hours
so 1400maH means that the batteries can supply 1.4 amps for 1 hour

the jeenyus · « **Reply #28 on:** March 16, 2009, 04:52:21 PM »

OK so do you think I need more powerful batteries? or is there something else wrong?

The power going to the servos is supposed to be 6V, but is only 2V on mine, and the power to the programmer and sensors should be 5V, but there is barely anything going through there. All my connections seem to be fine, but according to my pictures what do you guys think??? Do you think I should buy the 1800mAH batteries?

SmAsH · « **Reply #29 on:** March 16, 2009, 05:34:03 PM »

no, i dont think the problem is your batteries. it might be the cap or the vregulator. get another and test it and resolder if necassary.

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Author Topic: $50 robot electronics help (Read 5580 times)

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