Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: the jeenyus on March 10, 2009, 03:30:28 PM

Title: $50 robot electronics help
Post by: 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.
Title: Re: $50 robot electronics help
Post by: frodo on March 10, 2009, 03:41:36 PM
but i followed the directions excatly.

Are you sure you didn't put the voltage regulator in the wrong way round?
Title: Re: $50 robot electronics help
Post by: Soeren on March 10, 2009, 04:55:04 PM
Hi,

[...] 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?

Title: Re: $50 robot electronics help
Post by: the jeenyus 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!!!
Title: Re: $50 robot electronics help
Post by: frodo 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.
Title: Re: $50 robot electronics help
Post by: the jeenyus 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?
Title: Re: $50 robot electronics help
Post by: frodo on March 10, 2009, 05:21:39 PM
are the pictures posted on the internet at a website ie. photobucket?
Title: Re: $50 robot electronics help
Post by: 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?
Title: Re: $50 robot electronics help
Post by: SmAsH on March 10, 2009, 11:21:27 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.
Title: Re: $50 robot electronics help
Post by: dellagd 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.
Title: Re: $50 robot electronics help
Post by: the jeenyus 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
Title: Re: $50 robot electronics help
Post by: the jeenyus 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?
Title: Re: $50 robot electronics help
Post by: dellagd 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?
Title: Re: $50 robot electronics help
Post by: the jeenyus 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.
Title: Re: $50 robot electronics help
Post by: SmAsH 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!
Title: Re: $50 robot electronics help
Post by: dellagd 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?
Title: Re: $50 robot electronics help
Post by: SmAsH 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?
Title: Re: $50 robot electronics help
Post by: dellagd 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.
Title: Re: $50 robot electronics help
Post by: SmAsH 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 (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 (http://www.societyofrobots.com/images/sbs_avr_schematic.png) programmer outs.
http://www.societyofrobots.com/images/sbs_connect5_large.JPG (http://www.societyofrobots.com/images/sbs_connect5_large.JPG) large pic of what you want.
http://www.societyofrobots.com/images/sbs_connect7_large.JPG (http://www.societyofrobots.com/images/sbs_connect7_large.JPG) nother large pic of what you want.
Title: Re: $50 robot electronics help
Post by: the jeenyus 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?
Title: Re: $50 robot electronics help
Post by: dellagd 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.
Title: Re: $50 robot electronics help
Post by: SmAsH on March 13, 2009, 02:39:16 PM
yeap admins pins do look mighty bridged.
Title: Re: $50 robot electronics help
Post by: the jeenyus 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...
Title: Re: $50 robot electronics help
Post by: SmAsH on March 13, 2009, 06:37:11 PM
we'll always be here to help :)
Title: Re: $50 robot electronics help
Post by: dellagd on March 14, 2009, 05:51:17 AM
report back telling if that was the fix
Title: Re: $50 robot electronics help
Post by: the jeenyus 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
Title: Re: $50 robot electronics help
Post by: the jeenyus 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.
Title: Re: $50 robot electronics help
Post by: dellagd 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
Title: Re: $50 robot electronics help
Post by: the jeenyus 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?
Title: Re: $50 robot electronics help
Post by: SmAsH 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.
Title: Re: $50 robot electronics help
Post by: the jeenyus on March 16, 2009, 05:45:35 PM
ok thank you i definitely will.
Title: Re: $50 robot electronics help
Post by: the jeenyus on March 17, 2009, 04:53:45 PM
Ok, so I replaced the capacitor and the voltage regulator with new but identical parts, 5V Voltage Regulator and 220mF Electrolytic Capacitor. I then gave it a continuity test for good measure and this time was a little better. The servo section was about 3V this time, and the +5 power bus was 1V. I dont know whats wrong, I desperatelyneed help at this point...

 Please respond!
Title: Re: $50 robot electronics help
Post by: the jeenyus on March 17, 2009, 06:40:56 PM
I dont know if it matters, but I did not recharge my batteries since I got them, mostly because it is a battery pack and I have no idea how to recharge those... And I dont know if youre supposed to initially recharge them.

Any additional help would be appreciated!
Title: Re: $50 robot electronics help
Post by: SmAsH on March 18, 2009, 12:25:05 AM
well that may just be this problem!! check the voltage coming out of the pack. also try using a different battery.
and by 220mf you meant "uf" riggght?
Title: Re: $50 robot electronics help
Post by: the jeenyus on March 18, 2009, 01:57:39 PM
Ok Ill test the batteries... sorry I meant to say micro farrads, not megafarrads or whatever...Thank you very much I will test them
Title: Re: $50 robot electronics help
Post by: the jeenyus on March 18, 2009, 02:32:14 PM
Ok I tested the batteries, and there is about 3V coming out of my 6V battery pack.... very interesting.... So does that mean I should recharge them? Or are my batteries defective?

I will invest in a battery recharger, the kind that recharges battery packs, so what is recommended? Please help!

Thank you very much.
Title: Re: $50 robot electronics help
Post by: dellagd on March 18, 2009, 07:29:14 PM
look here
http://www.societyofrobots.com/step_by_step_robot_step3A.shtml (http://www.societyofrobots.com/step_by_step_robot_step3A.shtml)
scroll down about half way
it talks about chargers
Title: Re: $50 robot electronics help
Post by: SmAsH on March 18, 2009, 11:22:02 PM
lol, you would be suprised how many times the fault with peoples mcus is battery power.
Title: Re: $50 robot electronics help
Post by: the jeenyus on April 04, 2009, 07:56:57 PM
I charged up the batteries and it worked!!! About 7V going to servo pins, almost exactly 5V going to other pins.... I'm so glad it worked!!! I am going to go try downloading the servo hold program now... Wish me luck!!!!! Thank you guys so much! I really feel stupid that this whole time it was my batteries...
Title: Re: $50 robot electronics help
Post by: SmAsH on April 04, 2009, 08:01:46 PM
hehe, good luck
Title: Re: $50 robot electronics help
Post by: dellagd on April 04, 2009, 08:26:18 PM
hope it works! ;D
Title: Re: $50 robot electronics help
Post by: the jeenyus on April 04, 2009, 10:36:48 PM
Ok guys... something's wrong again.

I plugged in my programmer and it did not work after checking voltages many times, and switching usb ports many times and so on. I used the apparently not so good programmer, but I have the better one too. If I soldered the appropriate-sized male header onto the board, what are the connections I have to make? I read the posts concerning it and I am not entirely sure what to do, Do I just simply ignore all those pins that lead to ground that would not exist in the 6 pin? Where would I solder the lead of the ceramic capacitor? I am very frustrated; I do not know many things yet as you can tell. Please help I am very determined to finish this project.
Title: Re: $50 robot electronics help
Post by: bionic-man on April 04, 2009, 10:53:34 PM
you could just make a cable that goes from the 10 pin to the 6 pin couldnt you? like a converter type thing?
Title: Re: $50 robot electronics help
Post by: SmAsH on April 04, 2009, 10:57:19 PM
you could just make a cable that goes from the 10 pin to the 6 pin couldn't you? like a converter type thing?
that could work and may be easier than soldering on a new row of headers. but i thought the more expensive one came with a 6pin and 10pin cable and the 10-pin was just stuffed into the case?
Title: Re: $50 robot electronics help
Post by: Metal Slug 2 on April 04, 2009, 11:06:56 PM
I had a similar problem when i built my $50 robot - one time it would work great, the next time i tried to program it, nothing.

I went through every possible check i could do (or at least every one i knew how to do), wiring, proper set up of the .hex file i was tried to program, double cheaking frequencies etc.  yet none of that was the problem.  The problem was right under my nose...when fiddling around with my robot i had accidentally knocked the atmega8 mcu slightly out of its socket somehow, which had disconnected one of the pins leading to the program headers...i just pushed the ship back in and everything worked fine... ;) :D
Title: Re: $50 robot electronics help
Post by: the jeenyus on April 05, 2009, 10:53:04 AM
My AVR Programmer ISP2 Programmer did not come with a 10 pin header, only a 6 pin. How would I make a 6 to 10 pin converter? Please show me, I would like to be extremely clear on everything, because I do not know anything about programmers at all, but I would like to learn. Thank you for all your help.

Could it possibly be the micro controller? I dropped it once on carpet (not good) and I know it is static sensitive, so I have the feeling that it no longer works...
Title: Re: $50 robot electronics help
Post by: Metal Slug 2 on April 05, 2009, 12:02:09 PM
dropping your microcontroller on the carpet shouldnt have harmed it. :)

as for switching from a 10 pin to 6 pin programming header, i would just leave the 10 pin header on and add a 6 pin programing header somewhere else on the board...or just rewire the 10 pin header (and bend the two extra remaining pins down).  Read over this carefully:  (download the schematic made by Webbot)

http://www.societyofrobots.com/robotforum/index.php?topic=3292.0 (http://www.societyofrobots.com/robotforum/index.php?topic=3292.0)
Title: Re: $50 robot electronics help
Post by: superchiku on April 05, 2009, 12:11:07 PM
umm...10 pin header generally consists of all the connections as the 6 piin one ...along with that it has got some extra ground connection ...i think i u dont use those ground connection the also it will work..
Title: Re: $50 robot electronics help
Post by: SmAsH on April 05, 2009, 01:45:03 PM
yup, all 10 pin has is 3 extra gnd and one nc.
Title: Re: $50 robot electronics help
Post by: the jeenyus on April 05, 2009, 08:14:34 PM
Wow that diagram from that post is very helpful. Thank you very much. I didn't think to check that post... Last time I looked at that post I was not a member and could not download that file. Thank you for directing me there very much.
Title: Re: $50 robot electronics help
Post by: the jeenyus on April 06, 2009, 04:15:38 PM
Thank you for all your help, I have sucessfully programmed the microcontroller with the hold servo program. I really appreciate all of your help.
Title: Re: $50 robot electronics help
Post by: dellagd on April 06, 2009, 04:31:13 PM
fell free to ask for help any time or to PM me.
I love getting PMs
Title: Re: $50 robot electronics help
Post by: SmAsH on April 07, 2009, 12:26:26 AM
fell free to ask for help any time or to PM me.
I love getting PMs
i know right? that rush to look up at the top of the screen and see a new number!
to superchiku, we are saying we love getting pm's.
Title: Re: $50 robot electronics help
Post by: superchiku on April 07, 2009, 01:11:41 AM
 ;D wth are u all saying ? ?
Title: Re: $50 robot electronics help
Post by: robotmaniac on October 28, 2011, 10:28:09 PM
i found your problem. Its your Capacitor I'm pretty sure its rated 220uF 35V and 35 is way to high you just went to radioshack and said -o look the capacitor!!!!! its 220uF just what I need-and bought it. Same thing I did.LOL but no worries dud I'm pretty sure is that. You get a message that says-Target has lost power, or ISP programmer was disconnected-??????
Title: Re: $50 robot electronics help
Post by: Soeren on October 29, 2011, 01:07:47 AM
Hi,

i found your problem. Its your Capacitor I'm pretty sure its rated 220uF 35V and 35 is way to high [...]
Thanks for reviving an old-old topic.

A capacitors voltage rating doesn't matter, as long as it's at least a bit higher than the voltage it sees, so for eg. 5V circuits, you can use a 10V cap, a 100V cap or even higher.