Guide QT110 Touch-Sensitive Button Guide

ok I ordered those transisitors. i should have them in a few days I hope. but for the 10K resistors, I think I may have some but if I dont I have some 10K Potentiometers. Could I use one of those instead?

 

That would work but it would be bulky and a waste of a petentiometer! Anywhere from around 7k to 10k would be fine. You can use a couple of bigger resistors in parrallel or smaller ones together in series to get in this range, which means a more compact circuit using cheaper parts. But if you are just mocking it up for testing then go for it i guess!

 

ya i know itd be bulky but I only need one and i have a bunch laying around. i'll see if i do have a resistor of the correct rating but otherwise i'll just use potentiometer.

 

where does mobo wire go to?

Hello All

I plan on using this switch to turn my computer on and off.

I've gleaned from all the info here that the wire that goes to the mobo gives off a ground signal if the qt113 is a low chip.

i was looking at my mobo, and the PWR header has a GRND & PWR+ pin. Does the wire from the switch connect to the PWR+ pin? Or the GRND pin?

I'm also using this switch for my dvd drive. I assume I can just take the wire from the switch, turn it on by touching the switch, and try touching either of the pins on the dvd switch to see which one will open it?

Thanks all!

 

1) pwr+, it's the trigger/signal pin. Earth is already earthed, so earthing this means no change/action.

2) ya, or you could use a multimeter on the two pins - one will be earthed already, the other is the trigger that gets shorted to earth when you push the button.

 

Thanks agusta!!

Here's another silly question. I ordered a bunch of caps, but didn't notice they are rated for 600VDC!!! so they came, and they are like the size of pennies. should i get some smaller ones? i read earlier that 15VDC is good?

 

They'll be fine. 600v is their rated maximum, thats all. I'll guess that they'll probably have more leakage than 15v versions or something like that (wiki or google it for an accurate answer) but this circuit isn't a high frequency thing or anything like that so you'll be fine

 

thanks agusta! im going to give it a try. here goes nothing!

 

I have read every post...twice, and still don't quite understand exactly which parts needs to be ordered for like a 10 button panel. I will probably run through this again later when I have had some sleep. But I am surprised that no one is making a few extra of these and selling them for a small profit.

 

I have been looking for a touch sensor that is already setup and ready to use, but have yet to be able to find any...so I guess I will have to make my own.

I have (276-150) PCB, and (271-1124) 4.7k-ohm resistors from Radio Shack. I do have other various resistors, some capacitors, 555 timers, and transistors also. I don't think I need the sounder...but from what I understand I will also need:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=427-1000-ND
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=A24802-ND

Are these correct?

What I am thinking is making a board that will accept a molex connector as its power source, or another easy way to connect/disconnect, and supply enough power for 4 touch buttons. These will control the on/off, reset, and 2 optical drives. I also would like to supply power to LED's coming from the HDD's and computer itself. Is there an efficient way to do this off of 1 board? Can someone put up a small diagram (for idiots ) that I can follow to make this happen? I don't want to have 4 different boards for this as I am trying to save space for the small case I am working on. Thanks for any help.

 

If i'm not mistaken, the newest version is the qt113 which is supposed to be more accurate/sensitive. I got my qt113's from newark:

http://www.newark.com/92K8427/supplier-direct-ship/product.us0?sku=QUANTUM-RESEARCH-GROUP-QT113-DG

hurry though, i ordered mine like 2-3 weeks ago and the quantity left was at 400, now its 230 something. haven't put it together yet though.

 

Since you are already searching digikey for parts, why not just buy one of the ready-made q-touch demo boards? I've bought a couple of different ones from them before, and they are great, and not that expensive either (compared to making your own).....just a suggestion

 

Ok, but what about the other part...are you getting that from the same place, and where on the site were you able to find it cause when I order I would rather order everything that I need from 1 site.

 

Please forgive my "noobness"...I photoshoped one of the OP's pics so I could get a better understanding here...

Please correct anything that I might have misunderstood.

1-8: IC chip
11, 12, 15, 20, 21, 22, 23: Jumpers
9 connects to 7 through Jumper 12
10 connects to 6 through Jumper 11
13 connects to 8 and to negative side of LED
14 connects to 2 and to positive side of LED
16: output to motherboard??? (how with just 1 wire?)
17 is another Jumper between 1 and 3
18 connects to 1 and to +5v
19 connects to 8 and to any ground
24 is a 100kOhm resistor
25 comes from (metal?) touch electrode, through Jumpers and resistor, to connect 9 and 10?

After all this is done, the QT110 or QT113 can be attached to the IC chip.

 

Looking back over everything, post #4 says "Cs is supposed to be a 10nF (.01uF) non-electrolytic capacitor"...which it shows going between what I have labeled 9 and 10. I have two different packages...one which is 20 misc Electrolytic Capacitors, and two which is 0.1uF Polyester Film Capacitor. The second package is what is supposed to go here instead of the resistor (labeled 24) since I do not need the piezo sounder correct?

 

hmm..... mvagusta had a great schematic up of the simple circuit but it dont work!!

HINT HINT!!! *cough*


while you fixing link to schematic mvagusta could you clarify something about the transistor for me?

do the transistors require a constant output (setting the qt113 to toggle mode) or just a pulse to turn it on or off ( regular mode for qt113 )????

thanks!

 

OK...I have tried to simplify my redneck understanding of how his works. Since I should not need the resistor, nor the sounder, I do not need the extra jumpers run across the board and I should be able to set a board up like this:



If I can have it working this way, I can have 4 of these on the same board that will work independently from each other. Please let me know if this is a correct layout, and what exactly will the LED do when I have it attached to the leads. I am wanting to order all the parts that I do not have by the end of the weekend.

 

I'm all for making your own stuff, but if you don't have to.....4-button q-touch
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=427-1113-ND

 

I would still have no way to know how to hook this up to a computer. I also figure (if I am correct about my redneck-schematic ) that people here would be more able to point me in the right direction than something nobody has used yet. All I have left to buy to make this work is the IC chips and the QT110 or QT113 for each one. Like $10 US more I believe.

 

Your latest pic looks fine recoil

That led will turn on when you have activated the sensor. So when you touch the sensor, the led will light, and remain lit until you let go.

If also hooked up to mobo, the pc will turn on with one touch, but let go, touch again, and the pc will shut down - you may have to touch for 10 seconds depending on bios settings. The touch sensor will behave in the same way as a pc power button would.

And taladega, the transistor stays on whenever it is triggered from it's base, via the qt113 output. So if you want the transistor to run in toggle mode, set the qt113 to toggle.
The schematic i had up was from page 5, just with the transistor added.