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relay power supply question — Parallax Forums

relay power supply question

firealarmfreakfirealarmfreak Posts: 105
edited 2008-07-08 03:42 in BASIC Stamp
Hey my relays that were soldered recently broke (wires came off solder) The only other relays I have access to where i live are 12 VDC 5 amp dpdt relays in which fit on a breaboard (checked).

My only problem is I was using the 5 volt regulator on the board of education by parallax before to power them because my last ones that broke were 5VDC.

I do have a 12 volt transformer so can I still have the basic stamp pin activate a tranister and then actiavte the relay only using an external power source to energize the coils? in other words, instead of using VDD and VSS on the Board of education, just use the + and - on my 12 volt power supply.

Thanks.

Chris.
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Comments

  • FranklinFranklin Posts: 4,747
    edited 2008-07-05 03:51
    Show us how you plan to hook them up. You should not have been using the onboard regulator to power the relays as that can cause all sorts of problems with the stamp.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-05 05:07
    Hey heres a schematic diagram of my whole set up on the board of education including how i plan to set up my relays. Please not the bell and strobe are going to be connected to the same power supply (18 VDC) and the 2 relays will also be connected to the same power supply (12 volt DC) Its a 2 zone fire alarm control panel im making. Please note i did get help from the youtube user "newageserveralarm" so the schematic is based of his. Just to give him some credit too. I also mention that in the bottom right hand corner of the schematic.

    Hope this helps you help me.

    Chris.

    http://image69.webshots.com/169/5/25/86/2408525860102854175FARgFK_fs.jpg
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-05 06:00
    I looked at your diagram. The transistor circuit is still wrong. It's set up as an "emitter follower" and won't work properly as you've drawn it. This particular configuration is even less likely to work at 12V than at 5V because the relay is in the base drive circuit. You've also got the 12V supply backwards. Please follow the directions in the Industrial Control tutorial.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-05 06:32
    well the transister circuit is wired as some other person told me to cuz he wired his like it and it worked so he sent me the schematic. And it did work before, just not for the bell.

    I did follow the directions you gave me.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 03:17
    I made a WAY better diagram that only cantains how i plan to connect the 12 volt relays. Here it is:

    http://image24.webshots.com/665/3/2/56/2797302560102854175HaKGlR_fs.jpg

    I forgot the protection diode on the diagram, i will add it to the circuit though.

    Please let me know if this will let me use my 12 volt relays.

    Post Edited (firealarmfreak) : 7/7/2008 3:23:33 AM GMT
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 03:31
    I've told you before how to connect a switching transistor between a Stamp and a relay. This diagram still shows an emitter follower configuration. It won't work at 12V.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 03:32
    if i do it correctly is there any way of using 12 volt dc?
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 03:38
    Yes, if you wire the transistor the way I described, it should work at 12V. The emitter is connected to ground, the collector is connected to one end of the relay coil and the other end of the relay coil is connected to +12V. The ground of the 12V supply needs to be connected to the ground (Vss) of the Stamp board. You must have a protective diode with the cathode connected to the +12V end of the relay and the anode connected to the collector end of the relay coil. The base is connected through a resistor to a Stamp I/O pin. A value like 330 Ohms would work well. If you don't have that, a value between 470 Ohms and 1K would work.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 03:41
    ok can you make me a diagram and i promise i will wire it up as the diagram? post the diagram if at all possible. Thanks.
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 03:44
    Look at Figure 6.3 in this Nuts and Volts Column (www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol1/col/nv6.pdf).
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 03:57
    so if i wire it correctly as you described, the basic stamp should switch on a transister which should switch on the relay ?
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 04:13
    Please read the article. It explains this issue quite well
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 04:28
    Here is another diagram I made based on how i plan to hook it up acording to the artilce you sent me. Is my diagram correct now? and forgot the diode again, i will put it in when i make the circuit.

    http://image60.webshots.com/660/6/82/71/2032682710102854175ZAIXnj_fs.jpg

    Chris.
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 04:40
    The diagram looks correct as far as I can tell except for the lack of a diode. The transistor is not marked as to which lead is which. You'll just have to check the datasheet for which lead is collector / emitter / base. Don't assume anything.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 04:43
    yes i will check online and yes i will put a diode in there. The diode goes between the + coil and the collector correct?
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 04:45
    I already described in detail how to connect the diode. Please read my messages.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 14:56
    Hey my friend told me to use this diagram when using 5 VDC relays. Is this correct?

    PS. I did not make this particular diagram.
    Relay Circuit.png
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  • allanlane5allanlane5 Posts: 3,815
    edited 2008-07-07 15:00
    Mike, I just wanted to thank you for your patience in dealing with this issue.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 15:37
    All im doing is trying to understand why things dont work one way, even though they work another. I dont understand why everyone is making it into a HUGE issue.
  • Mike GreenMike Green Posts: 23,101
    edited 2008-07-07 17:00
    I have already given you all the information you need to understand how things are supposed to work. I suggest you spend some time looking up things like transistors and how they work on the wikipedia. I suggest that you browse through the various Nuts and Volts Columns dealing with driving motors and relays using switching transistors of different types. I suggest that you go through the various tutorials available from Parallax in the Stamps in Class tutorial series and work through the examples having to do with driving relays, LEDs, etc. There is more than enough information available, much better written and described than I can provide.
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 22:01
    Mike, I wired the transister and relay how you said and the relay never went on and off even though i programmed it too. All that happend is the relay energized once.
  • FranklinFranklin Posts: 4,747
    edited 2008-07-07 22:03
    So you don't have it right yet. Go back and do some more reading. Perhaps you could make a model of your system with switches instead of the stamp and make sure your idea works there.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 22:06
    Why cant somebody justd draw me a FREAKING diagram so i can make it work? All i need is someone to edit my exisiting diagarm to make it so its correct:

    http://image60.webshots.com/660/6/82/71/2032682710102854175ZAIXnj_fs.jpg
  • FranklinFranklin Posts: 4,747
    edited 2008-07-07 22:17
    Probably because you haven't taken the time to get software to draw a diagram most of us can decipher. If you won't do your work why do you expect us to go out of our way to help. If this is to much of a challenge get the industrial controll pdf and start working on those examples until you understand the underlying concepts. Good luck with your education.

    (I may be the only one that feels this way so I shouldn't have used 'we' in this post and I appologize to those that don't feel the same as I do.)

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 22:24
    what the heck kind of diagram do you want????????? everybody else i sent mine too can easily understand it...
  • kenwtnkenwtn Posts: 250
    edited 2008-07-07 22:35
    I think you need to share a common ground with the BOE and the Bell

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    Keep buying replacement parts and sooner or later you will get it RIGHT!
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-07 22:55
    Ok I have POSTED a new diagram. Please modify it and make it so that its all correct if its not already and then repost it or send it in a personal message to me. If you cant decyfer it, then i cant make a diagram for you.
    diagram.JPG
    1518 x 1461 - 62K
  • FranklinFranklin Posts: 4,747
    edited 2008-07-08 01:39
    Why do you have the coil of the relay going to 12vdc+ and the common going to 18vdc+? And where is your common ground between all this and the BOE?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-08 01:56
    my common ground is VSS and from what i understood mike told me to connect a relay coil to +12 volts. Mabe i read wrong.?
  • firealarmfreakfirealarmfreak Posts: 105
    edited 2008-07-08 02:39
    Ok here is a video of me explaining my set up and problem showing all my connections.

    This should be alot better then the diagram.

    Ok here is a video of me explaining my set up and problem showing all my connections.

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