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Guide QT110 Touch-Sensitive Button Guide

Discussion in 'Modding' started by gongzero, 16 Oct 2005.

  1. NZ_mod_man

    NZ_mod_man What's a Dremel?

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    Here is another way to get +5VSB power as done buy gongzero himself back in post #5.
     
  2. talladega

    talladega I'm Squidward

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    gotta question about your schematic

    on some of the capacitors there is a positive sign on one side of it, while others there isnt. does this mean anything?

    also on C4, C6, and C7 the capacitor rating only has a U thing after it and not UF. is that correct or a mistake? I assume its supposed to be UF right?

    finally what type of capacitors are the cheapest (but still good to use)? I see there are ceramic, electrolytic, poly film, tantalum. And what voltage rating do I get? Under C7 it says 15V so I guess that means that capacitor should be 15V but what about the others?

    im trying to narrow down my search so I can make these circuits for as little as possible.


    thanks!!!


    edit:::

    based on my assumptions and interpretations of what everything is im not so sure i have got everything chosen correctly as i have made a list of every single component and tried to get low prices and it turn out to be like $10-11 per circuit for me. :(

    would you be willing to look over what ive chosen if i post the list?

    if it correct then i dunno if im even gonna make this double tap circuit. maybe just for the power button. the main reason i want to do this is to prevent accidentally turning off or resetting computer.
     
    Last edited: 16 Feb 2008
  3. muther trucker

    muther trucker I've got a Dremel?

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    Argh, the images have all gone.

    Darn.

    Can anyone upload them again?

    It would be great if everyone could see them again, especially those wanting to use them for a project!

    :)
     
  4. Ending Credits

    Ending Credits Bunned

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    I'm thinking of using a couple of these as mouse buttons, would this work?
     
  5. Ending Credits

    Ending Credits Bunned

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    Sorry for the bump but does anyone for-see any problems.
     
  6. talladega

    talladega I'm Squidward

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    i dont see why it wouldnt. as long as you can wire it up I would think itd work.

    just dont use it for gaming as there is lag in it. otherwise itd be fine i think.
     
  7. rope1111

    rope1111 What's a Dremel?

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    Thanks for such a nice informative post, I was looking for such kinda thing for long. Thanks again, n i am really very happy and proud to post my first post here :)


    _____________
    Chanel Bag
     
  8. talladega

    talladega I'm Squidward

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    Well, I just ordered enough stuff for 8 of the regular circuits. I should have it for Saturday so I can put my case together next week.

    Could someone post a diagram of how to do a latching circuit? Thanks
     
  9. Ending Credits

    Ending Credits Bunned

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    D type flip flop?
     
  10. talladega

    talladega I'm Squidward

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    what? explain...
     
  11. Ending Credits

    Ending Credits Bunned

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    Well there's many types of latches and ways to use them.

    Google is pretty good when it comes to pinouts/diagrams.

    Better than me I mean. :p
     
  12. talladega

    talladega I'm Squidward

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    mvagusta i need a little help here! :)

    I got my chips and stuff and just finished soldering wires onto the pins. on your diagram you have pin 3 and 4 goin to VDD (pin 1). based o the data sheet that is just a 10 second on duration. will anything screw up if I do pin 3 to VDD and pin 4 to GND (60 second on duration)??

    also, you have that 0.1uf capacitor on the VDD pin. does the other side of the capacitor go to ground or where does it go?

    finally, I can use the same +5V source for all my circuits right?

    oops one more question. :) How do I wire up these circuits to power on my case lights? I have 4 30cm UV Cathode lights. I know that I need to have Pin3 and Pin4 to GND for a toggle switch but how do I make this circuit turn the power on and off for the lights?

    Thank You!
     
    Last edited: 12 Apr 2008
  13. mvagusta

    mvagusta Did a skid that went for two weeks.

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    I expect attaching pin 4 to gnd for 60 second duration should be fine - i haven't tried that but i think it would be ok. The thing is, i dunno why you'd want 60 second duration, cos you'd have to keep your finger on the sensor for 60 seconds for the output to stay on for 60 seconds.

    That .1 uf cap is just there for fine noise filtering/de-coupling - the cap should be soldered to the vdd & gnd pins of the chip or socket, and the gnd should be soldered as close as possible to the pin - leave ~5mm lead length on the +ve side if needed, and the gnd lead of the cap must be <3mm to the gnd pin, to maintain anti-noise properties of the cap.

    The one +5v can go around like a whore at a brothel

    I guess you'd need some sort of latch for this circuit to keep case lighting on until the senor is re-activated, otherwise the lighting will turn off as soon as you let go of the sensor.

    The other thing is, either way, latch or not, you'd need a transistor switch to drive the current of the cathodes! The logic output of chips such as the qt-113 is ok for a couple of leds, that's about it.
     
  14. talladega

    talladega I'm Squidward

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    i want 60 second duration because sometimes you need to turn computer off by holding down power button for longer than 10 seconds. :)

    for the lights I would set the output mode to toggle. (Pin3 to GND, Pin4 to GND). So when you touch it turn on and then touch again to turn off. So I would need to use a relay to then control the power of the cathodes? Thats I think what my dad had said a while back but I havent talked to him about this much.


    for the 0.1uf cap i basically cut the leads on the cap down so they are as short as possibl and directly solder onto the VDD and VSS pins, correct?

    thank you!
     
  15. mvagusta

    mvagusta Did a skid that went for two weeks.

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    Toggle mode is perfect, no need for an external latch :duh: I must have forgotten about that option :D

    You can use a relay, but the output of the chip is not to exceed 20ma, so you'd need a transistor switch to drive the relay.

    A few cathodes will use around 1a i'm guessing, it depends the type. The benefit of just using a transistor switch and no relay is that there is no click sound. It's at least as reliable provided the transistor is rated at least double the current the cathodes will be pulling through it!
    If there is a little heat, then attaching the transistor to the case will be a great heatsink to get rid of that, but the transistor will run cool without a heatsink if it's beefy enough, say 3 or 4 amps.

    Unless you want the click sound, then only the small load of your chosen relay has to be carried by the transistor switch.

    The .1 uf cap is best soldered to the pins directly, but can be just soldered to the socket's pins if you are using sockets?
    The lead length of the cap to the -ve pin must be short as possible, <3mm. It's ok if the +v side has to have a lead of say 5mm or so.
    I'd solder it first, then cut the leads - if the joint is made quickly, then the long leads work really well as a heatsink, helping to draw the heat from the join away from the internals of the ic.
     
  16. talladega

    talladega I'm Squidward

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    I soldered up one of the momentary cuircuits. Used a 0.033uf cap for the sensitivity. havent tested yet but I can always swap it out if not sensitive or too senstive.

    I'll see if i can take a pic of the circuit. It will make you lol for sure. :)

    Heres the lights im gonna be using. http://www.petrastechshop.com/lo12ducocaki4.html
    I have 2 of these kits and want them all hooked up to one circuit.

    ummm what do i type in on www.Digikey.com to find the transistor switch I need? :) its confusing.
     
  17. mvagusta

    mvagusta Did a skid that went for two weeks.

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    The 5ma current quoted must be the output current @ 680v. I'm guessing the input current would be around 350ma maybe :confused: So at a guess, for 4 cathodes, we might be supplying around 1.4a, so a transistor of say 3a or more should run cool. this guy should run cool, since it's rated at 5a!

    Don't forget to use my previous link to see heaps of info on how to hook up a transistor as a switch.

    Basically just qt113 output > 10k resistor > base of transistor

    And the other two legs of the transistor are the gate/switch/power path to connect the cathodes to ground.
     
  18. talladega

    talladega I'm Squidward

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    I see. thank you! Always better to get one rated higher than you need just incase. :)

    so resister between output. and then i would take off the two wires from the switch included with the lights and connect to the other two legs. w00t. I guess I'll order this bad boy. :p Maybe a couple just incase I mess up. :D

    argh! No paypal with Digikey. I looked on eBay and found this. http://cgi.ebay.com/TIP121-NPN-Epit...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

    That one good too? Different resistor required?
     
    Last edited: 15 Apr 2008
  19. mvagusta

    mvagusta Did a skid that went for two weeks.

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    Your description of the transistor circuit doesn't sound right tho.... i'm guessing you didn't read any of the links on how to use a transistor as a switch!
    [​IMG]

    That tip 121 will be fine, 10k is still good, just make sure you download & read the datasheet, to figure out which pins are the Base, Collector & Emitter.
     
  20. talladega

    talladega I'm Squidward

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    i dont understand that fancy stuff that will be explained in the links but I know how it works. I no good at explainin that stuff but yes that is exactly how I pictured it. Those 12v and GND wires are the wires that currently go to the prebuilt switch that comes with the lights.

    Yes I read datasheet to see which pins are which. :D

    thanks!!
     
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