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Electronics Any Electronics buffs got a minute...

Discussion in 'Modding' started by Dr_kazza, 9 Sep 2002.

  1. Dr_kazza

    Dr_kazza What's a Dremel?

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    I found some really nice switches on Maplin but they are push to make switches rather than toggle... i.e. they're like a doorbell not like a TV on switch.

    If anyone has a minute could you design a pretty simple circuit for me... I'm after one of the switches to toggle a CC on/off...
    i.e. you start off with the CC off and press the button (to send a signal) and it toggles to on.

    If you use any IC... could you let me know the name/maplin number cos I'm not very good with this stuff... finally got the guts to play with an opto isolator which was cool and worked :) so I'm not completely inept.

    Thanks :):)
     
  2. nesbit37

    nesbit37 Guest

    Moved to electronics---

    There really isn't much need for a circuit to design for that but if you post the switch's part number it would help. We do need to know if the switches are momentary. single pull single throw, single pull double throw ect. I can tell you now no ic's will be used. If all you want it to do is turn the cc on and off it should be the switch, the cc's inverter and 2 or 3 wires (depending on switch type).

    If you want a decent explenation with some good complementery graphics on how simple switches work you should check out this web site

    -Nesbit
     
  3. Dr_kazza

    Dr_kazza What's a Dremel?

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    The switches I'm after are the CL89W which apparently look a lot like the MG74R except they have an LED.

    Apparently they are SPNO (that's momentary right?) but I want it to act like a light switch... i.e. press once circuit on.. press again circuit off.

    Thx

    kazza

    P.s. I only chose those switches because I HATE the flick switches that most people use for baybusses and couldn't find any nice steel/Aluminium switches/buttons to match the case
     
  4. eaterofpies

    eaterofpies What's a Dremel?

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    ive worked out how to do it but u wil need something to boost the power like a relay or transistor or summat i dont know how much current a cc takes so i cant suggest

    what u need is a d type flip flop

    then u connect the D pin to q(with a bar over the top) then the clock pin to the switch and the q(without a bar) to your transistor or relay etc i have a pic which is easier to show but i dont have ne hosting
     
  5. Dr_kazza

    Dr_kazza What's a Dremel?

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    Can anyone nice host it for him :):) and do you have a maplin code :)
     
  6. :: Phat ::

    :: Phat :: Oooh shakalaka!

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    You can use a "Latch" and a double relay. Push the button to "latch" the latch, this in turn turns on the relay to give power to whatever, but the relay also re-routes the switch so that it shorts the latch if pressed again therefore re-setting the latch. :D
     
  7. Dr_kazza

    Dr_kazza What's a Dremel?

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    kinda makes sense... do you have a circuit diagram or maplin codes... [/inept]
     
  8. :: Phat ::

    :: Phat :: Oooh shakalaka!

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    I would draw you one up right now, but I can't get onto my server from work and if you expect me to go through the crap that needs to be filed before I can place an image on the work server you'll be gravely mistaked... I'll knock one up tonight If no one's beaten me to it :D
     
  9. cpemma

    cpemma Ecky thump

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    /me likes latching relay. You can't see the electricity in these ic things. :eeek:
     
  10. ducktape

    ducktape What's a Dremel?

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    Here is a quick diagram.

    Hi, This circuit should do it. if you don't reaally want to traul through the maplin catalouge to find all the components then i can do it for you, just sayso. also i can re draw the diagram for the components rather than this slightly unfrienly looking thing.
    [​IMG]

    I believe this should work. i've shown it with pc psu voltages, because i assume thats what you'll b using. if not just say so and i'll alter this.
    If anyone thinks i've missed something, or made a huge mistake please say so, but i believe this will work.

    oh btw, this is my first post on these forums, so b nice!:D
     
  11. eaterofpies

    eaterofpies What's a Dremel?

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    based on my d-type idea i see :) im glad some one else has ceoc clips :D

    EDIT not sure what io meant by ceoc clips i assume it was the idea or summat
    /me is a bit boozy

    Edit ceoc clips = croc clips - crocodile clips ive worked it out now (no doubt "borrowed" from s school or summat :D)
     
  12. ducktape

    ducktape What's a Dremel?

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    Crocodile Clips

    I may have used crocodile clips to aid with the drawing, but its only because i havn't got anything else, and using psp for everything is just tedious. anyway if the circuit is legable does it matter if i used electronics for telle-tubbies?:D
     
  13. cpemma

    cpemma Ecky thump

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    Re: Crocodile Clips

    "Don't apologise, it's a sign of weakness" - John Wayne

    If Crocodile Clips is good enough for Westminster School it'll do for us commoners. :lol:
     
  14. Dr_kazza

    Dr_kazza What's a Dremel?

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    I'd be very grateful... (5 dollar sucky sucky)... if someone could dig up the Flip flop, relay and Transisitor maplin codes :):)

    I assume that the relay although a magnet isn't going to have any effect on HDD/Floppy [/dimquestion]

    Thanks

    Kazza
     
  15. ducktape

    ducktape What's a Dremel?

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    i'll have a flick through the maplin catalouge, but i've just been phoned by work, and i have 2 work tonight, so it won't be until i get in at about 00:00 GMT. i'll do it then if no one else has.

    Oh, and although the relay is a magnet (when energzed) you won't need a big one, and it shouldn't affect anything in your case. just to be on the safe side don't mount it too close to any magnetic drives. but like i said, it shouldn't b a problem.

    oh, btw i'm assuming the cold cathodes run on 12vDC or less, if not then tell me now, so i can look up the right relay.
     
  16. Dr_kazza

    Dr_kazza What's a Dremel?

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    Yup will all be 12V... Big kiss in the post to do Ducktape

    Cheers matey
     
  17. ducktape

    ducktape What's a Dremel?

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    Here We go

    I've modded my original circuit a bit. it has another ic chip in it, but no transistor this time. also i've wired it up a bit different.
    I'll explain. your switches are push to make (thats what you said). as with any switch there will be something called bounce. this basically means that when the switch is first thrown, or pressed the signal won't be very clean. because i'm feeding this signal into the clock input of a logic gate, this could mean you light goes on-off-on-off again, very quick (in a fraction of a second) so, we have to get rid of the bounce. a circuit called a schmitt trigger is used to do this. to make things simple, there is a chip with 6 of these things on it, but it inverts the signal. this doesn't matter, as we can feed it back through the schmitt to re-invert it. i've chosen not to do this, but to make the switch part of a potential divider circut that 'sinks' the current to ground when the button is pressed. this has two advantages
    1. is means the switch is acting like a push to break switch (as far as the logic signals go)
    2. it means the logic circuit gets a clean +5V and 0V signal to work with, which can stop problems appearing (like random switching on or off!)

    so, that explains the pressence of the potential divider and 7414 chip. I'll now explain why there are two switches. this is because there are two d-type latches on the 7474 chip, and i wanted to show you how to connect two up if you wanted to, rather than making a whole new circuit. If you only want one switch, then all the blue wires can be removed. if you want more than two buttons, then you can add more 7474 chips, and use the 7414 chip upto for upto 6 buttons, but for now, i'll leave it you can ask if you want more.

    ok, just a quick note. wires are only conected to other wires if there is a blob, not if they just cross.

    I've managed to leave out a transistor or other driver circuitry, because we are going to use Reed Relays. these use very little current (10mA), and can be driven directaly for 74 series logic. ( thats the type were using)

    Right i think thats it, accept to say, that if when you put this all together it doesn't work properly, then tell me, because i could be a very simple problem with me not telling you to wire up all the un-used pins on the ic's. i don't think it'll b a problem, but occasionally it is. last year, on my a-level project i spent ages trying to fault find, and that was the problem all along:grr:
    ok, i think thats it. right, heres the diagram:
    [​IMG]

    and here is a maplin parts list!!

    Relay - Sealed Reed Relay - JH16S £1.49
    74LS14 - Hex schmitt inv. -YF12N £0.34
    7474 - Dual D-Type Flip-Flop -QX59P £0.69
    1K Res - 1K resistor -M1K £0.07

    the buttons, are down to you, and so is anything else you may need, eg power connectors and wire.

    good luck. tell me what comes of it. i want to know
     
  18. Dr_kazza

    Dr_kazza What's a Dremel?

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    MOOOOOVE YOUR EARS.... (sorry mate just saw the scooter reference in your siggy - go listen to the song "move your ass" and then listen to how his lovely german accent says Ass... one for gary lineker! :) :wobbleears: )

    Anyway that circuit is great... I'll order the stuff now and hopefully will have it built by the end of the weekend... (14hr working days aren't condusive to hobbies ;) )

    This is great... so effectively the end result is Press button once CC on... Press button again CC off?

    I'll post piccies when done :):)

    Cheers

    Kazza
     
  19. Dr_kazza

    Dr_kazza What's a Dremel?

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    ROFL... just found a similar switch at RS which is DPDT...

    I'm going your route now anyway... more fun! :)
     
  20. ducktape

    ducktape What's a Dremel?

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    DOH, nevermind. you get that sense of satasfaction when you've spent hours building something yourself, the you come to use it and it dies or doesn't work!!:cries:
    Still, this should do
    have fun
     

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