Circuit Verification - Made with matrix board and copper tape

Discussion in 'The Projects Forum' started by juve786, Jul 27, 2010.

  1. juve786

    Thread Starter Member

    Jul 13, 2010
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    Hello there,

    I have a very low budget, so dont have a etching kit for making circuits. As a hobbyist I used to make random circuits on breadboard..and im sure after you find them working, you would like to make them permanent...

    I make my circuits permanent by designing a track design on circuit wizard and copying out the designs with copper tape onto a matrix board. I have done this with one circuit and was having trouble with it until this forum helped me realize the capacitor was backwards, however I am having another issue with another circuit and need help verifying the design.

    It is the spaceflag project found here and I have repeatedly checked to see my design matches the schematic, and the connections seem right. I have come to believe the chip is faulty. (Yes the capacitors are connected correctly lol)

    I contacted the supplier and they said they have never received any issues with the chips to date and said that providing i really did check my circuit correctly, there may be 2 possibilities of error.. "the program is faulty some where or the circuit is not a good design for the chip"

    I contacted Madlab asking about any program (because they provide them,if needed, on the website) and this kit does not require any as the circuit does the programming, so the last option is that the design is flawed.

    Before I contact my supplier again I would like to ensure 100% that the design is OK. I have attached the design, and have compared both it, and the actual circuit board outcome with the schematic. Those seem correct and since i have made it with copper tape, i have checked every connection with a continuity checker.

    Can someone please verify my design?
    Thanks a bunch!

    p.s - yes I have mirrored the design onto the back of the board
     
  2. tom66

    Senior Member

    May 9, 2009
    2,613
    213
    First, the chip is very likely to be in perfect working order, though faults still happen. It could have been damaged by static, though the PICs usually have excellent electrostatic discharge protection, to the point at which I have handled the chips by their pins with no issues to date... however, that is no reason to not take precautions.

    Upon analysis of your circuit, I notice the following problems:

    Your regulator is around the WRONG way! You have connected the output to the voltage input. Luckily, there is no need for a redesign, just reverse the regulator. See datasheet here: http://www.national.com/profile/snip.cgi/openDS=LM78L05

    The potentiometer's pin 3 is not connected. This will only act as a variable or possible even a fixed resistor (depending on the pin configuration which I am unsure of), which is probably not what you want.

    EDIT: It's quite possible that by doing this you have damaged your PIC. Verify the voltage using a multimeter. If it's any greater than about 7 volts you should probably replace it as you have exceeded the maximum ratings.
     
    Last edited: Jul 27, 2010
  3. juve786

    Thread Starter Member

    Jul 13, 2010
    27
    0
    embarrassingly, even after looking up the pins of the voltage regulator i was still confused about which is which - HOWEVER I have placed it correctly (and the diagram as it is on circuit wizard shows the input connected to the battery). lucky guess, eh? - I thought this was an issue before but checked everything with a multimeter (voltage) and it can successfully output 5VDC from 9... on the right side too :p

    regarding the potentiometer, I only used that in the schematic because circuit wizard does not have a TILT SWITCH. So although I cannot simulate the circuit, I put that there because it was the best fit for how the tilt switch would fit onto the board. So i should mention to please ignore the third pin and I apologize for that too! - i forgot I did that :(

    Other than what you suggested it seems that the design is fine? :confused:
    I have been told many times the chips are very 'robust' but I dont know what else it could be
     
  4. tom66

    Senior Member

    May 9, 2009
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    It is still not working?

    You have probably fried the PIC. 9 volts is way too much. 7 volts is pushing it. I would expect that the regulator could malfunction and output as much as 7.5 volts. Your only option is to replace the PIC.
     
  5. juve786

    Thread Starter Member

    Jul 13, 2010
    27
    0
    I only use a 9V battery later because I thought not enough voltage was going through the copper tape and soldering etc..

    Before even making the board I made it on a breadboard with no luck, and even straight after making the board. Both these times i used 4x 1.2V AA batterys = about 4.8V (5.3V measured on multimeter somehow lol).

    The voltage regulator always outputs 5V though, i dont understand how any more could have gone to the chip.. I only put the chip in the socket after I have completed and checked the circuit..

    EDIT: My last post before this one was meant to say the voltage regulator was ALWAYS in the correct position. Sorry for not making that clearer (im bad with phrasing :))
     
  6. tom66

    Senior Member

    May 9, 2009
    2,613
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    5.3V on multimeter because recharged Ni-MH cells reach up to 1.4V each.

    The input range is 2V-5.5V. In my experience you can put up to 6V in without problems. Can you just load an example program on to the PIC flashing an LED? Or is this not possible? Do you have a PICkit 2?
     
  7. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    No..
    I have never programmed PIC's so dont have any programming kits or softwares.. this is the first pic ive ever worked with..:(

    if it helps, i measured the voltage across the pins of the chip and find abt 5V at pin 1 and 0v at pin 8 (or 5v if i measure it backwards) so i know its getting power... i get nothing a the outputs..but being a flashing circuit i doubt i would get a steady output at any of the others?
     
  8. tom66

    Senior Member

    May 9, 2009
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    Your multimeter will average the output so you will get 2.5V if it is on 50% of the time. Do you not have any spare chips? Because I cannot think of any other possible faults.
     
  9. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    That is just the thing.. all i can think of is trying another chip but incase the circuit is faulty i do not want to spend money for nothing... If i am completely sure the circuit is fine my supplier said theyll replace it although a fault has NEVER been reported...
    otherwise no i do not have another chip at this time..

    i could try the multimeter again, what setting? VDC or VAC measurements?
     
  10. tom66

    Senior Member

    May 9, 2009
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    If it's got 5V regulator output it's unlikely to damage it, but I can't be sure.

    How much are these chips anyway? The 12F508/509 series are usually less than 30 cents each, even in small quantities. Perhaps the special program is what makes the chips so valuable... how many do you have?
     
  11. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    I only have the one possible faulty one...
    and you confused me - are u from UK or US? :rolleyes:
    its about 1-2GBP here
     
  12. tom66

    Senior Member

    May 9, 2009
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    UK but most components priced in US dollars because that's where they're made (in the US).

    Ouch, £2. That's quite a lot. :( Big markup on those! The chips are about £0.20 each, that's a 1000% markup.

    Since you only have one chip, there's not much I can suggest. Sorry. :( This is why I always buy two or three of every chip, but I guess since your chips are pretty pricey that's not always an option.
     
  13. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    as long as you say the design is correct, i might be able to get that replacement so ill let them know tomorrow and let you know the outcome.

    thanks for everything though! appreciate it loads :D
     
  14. windoze killa

    AAC Fanatic!

    Feb 23, 2006
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    I am curious, you said the supplier said "this kit does not require any as the circuit does the programming"...... NOT possible.

    You haven't actually said that the PIC came from the supplier already programmed. Did it or not? If not then thats why it is not working.
     
  15. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    oh no, the supplier (NOT madlab) obviously sent a 'blank' chip..

    I emailed the people who designed the circuit (madlab - see earlier posts) about any program i might need to make this work and they said i didnt need one..
    The circuit works (or should) by pressing the push buttons.. by doing this you are inputting a sequence of rapid flashes which, by using the persistence of vision, should spell out a word when waved in the air. Since you can wipe these 'words' clear and put in others, i understand how this chip may not need to be externally programmed?
    If my desription is unclear, please take a look at the project on the madlab link in my first post as it explains its funtion and everything in much more detail..
    They didnt say the circuit does the programming - just that i didnt need a program so i assumed and wrote myself that the circuit does the 'programming' (sorry if this is electronically incorrect)
     
  16. tom66

    Senior Member

    May 9, 2009
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    In order to program it, you would need the program, a computer to program it with, and the appropriate connection. If you ordered them from Madlab they may be programmed already.

    You can order samples from Microchip Technology pre-programmed.

    https://www.microchipdirect.com/programming/default.aspx

    They will probably send you some chips if you ask them nicely... I assume you're a student.
     
  17. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    here is part of the conversation with madlab:

    Me: should the spaceflag just work as soon as I install the new chip? currently nothing happens at all..

    Madlab: Yes it should. It's could be something else and not the chip.

    ----------------------------
    yes i am a student..currently between college and university.

    The thing that confuses me the most is that all of the PIC projects on madlabs website have any code there available on the site with them.

    in order to wipe the 'message' on this project, wouldnt any program be erased anyway?
     
  18. windoze killa

    AAC Fanatic!

    Feb 23, 2006
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    If it "just works" when you plug the chip in it is a miricale. A PIC is a Micro controller. If it doesn't have a program in it there will be nothing to control.

    With regards to losing your program you won't if it is stored in the flash memory on the chip.
     
  19. juve786

    Thread Starter Member

    Jul 13, 2010
    27
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    Hi guys. sorry for long wait but you wont believe what happened!
    I emailed madlab again, and yes it does need a program! :mad::mad::mad:
    what a waste of time.. and so i asked him to send it and he did - nice of him..

    but now i need to put the code in somehow - bare in mind i have NEVER worked with PIC's let along programmed them - nor do i have the stuff to..
    I wouldnt mind making a simple one? or idk because im realy baffled with what to do now.. i dont have money to spend either :(
    I had a quick look and got blown away by all the progammers and languages and whatnot...

    HELP!:(:eek:
     
  20. tom66

    Senior Member

    May 9, 2009
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    Unfortunately programmers aren't that cheap. I bought my PICkit 2 starter kit for about £40 here in the UK. That includes the programmer (the PICkit 2), a quick start guide, two software CDs, a demo board and a PIC16F690. It's worth it, because you don't have to buy one again. But, it's still a bit of money. Now days, Microchip have brought out a new programmer called the PICkit 3. You should really buy a PICkit 3 instead, but the starter kit starts at about £55 so it's considerably more. I don't have a PICkit 3 yet, but I will probably end up buying myself one because I'll need it for some of the newer chips, plus I'll have a spare programmer for most micros, my PICkit 2.
     
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