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Adafruit Touch Sensor Wiring

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May 2, 2017
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The build is almost complete and the only thing missing is the power switch, which I do not know how to wire.

I’ve done some reading and ended up ordering two kinds of sensors from Adafruit, as seen in Neil’s thread, as well as small relays that he uses to send a signal to the motherboard power switch pins. However, I could not find a definitive answer on how to wire the Adafruit touch sensor and the Omron low signal relay and then connect everything back to the power switch pins on the mobo.

Since I've already gone through one PicoPSU due to shorting, I just wanted to make sure this would be the correct procedure before I burn something else.

Neil's thread:

https://www.tonymacx86.com/threads/touch-sensors-three-models.155762/

AT42QT1010 - momentary sensor
AT42QT1012 - toggle




Low signal relay: Omron G6A-274P-ST40-US-DC5

http://eu.mouser.com/search/ProductDetail.aspx?r=653-G6A-274P40-DC5



Could someone please help me with wiring this? I understand that once the touch is sensed the sensor sends the signal to the relay, which in turn sends a low signal to the power switch pins.

Would this be correct:
  1. I’m already tapping directly into the PicoPSU to get +5V and wiring it to the VDD connector on the touch sensor
  2. I’m already taking ground directly from PicoPSU and wiring it to GND connector on the touch sensor
  3. Where should I then connect OUT from the touch sensor? I’m assuming this should go to the relay, but not sure which pin?
  4. Once the out line from the sensor is connected to the relay, which two pins should I use to send the signal back to the motherboard power switch pins?
I’m obviously not well versed in how relays work and would really appreciate some guidance. I thank you in advance.

Zoran
 

neilhart

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The build is almost complete and the only thing missing is the power switch, which I do not know how to wire.

I’ve done some reading and ended up ordering two kinds of sensors from Adafruit, as seen in Neil’s thread, as well as small relays that he uses to send a signal to the motherboard power switch pins. However, I could not find a definitive answer on how to wire the Adafruit touch sensor and the Omron low signal relay and then connect everything back to the power switch pins on the mobo.

Since I've already gone through one PicoPSU due to shorting, I just wanted to make sure this would be the correct procedure before I burn something else.

Neil's thread:

https://www.tonymacx86.com/threads/touch-sensors-three-models.155762/

AT42QT1010 - momentary sensor
AT42QT1012 - toggle




Low signal relay: Omron G6A-274P-ST40-US-DC5

http://eu.mouser.com/search/ProductDetail.aspx?r=653-G6A-274P40-DC5



Could someone please help me with wiring this? I understand that once the touch is sensed the sensor sends the signal to the relay, which in turn sends a low signal to the power switch pins.

Would this be correct:
  1. I’m already tapping directly into the PicoPSU to get +5V and wiring it to the VDD connector on the touch sensor
  2. I’m already taking ground directly from PicoPSU and wiring it to GND connector on the touch sensor
  3. Where should I then connect OUT from the touch sensor? I’m assuming this should go to the relay, but not sure which pin?
  4. Once the out line from the sensor is connected to the relay, which two pins should I use to send the signal back to the motherboard power switch pins?
I’m obviously not well versed in how relays work and would really appreciate some guidance. I thank you in advance.

Zoran
Sorry for not seeing this query earlier.

Anyway to wire the touch sensor and relay proceed as follows:

This circuit works with the 5 volt standby power (noted as 5VSB) from the PSU. The 5VSB is found on pin 9 of the 24 pin ATX power connector, usually a purple wire. If you use a 24 pin extender cable to relocate the PicoPSU then there is no problem of tapping into the pin 5 purple wire. Otherwise you will need to locate the 5VSB on the motherboard as it is many times to be found on one of the header pins (check the docs).

Wire connect the 5VSB to the VDD pin of the touch sensor.

Wire the touch sensor GND pin to the relay pin 16 (-) and to the PSU ground black wire (choose one pin: 3,5,7,15,17,18,19 or 24).

Wire the touch sensor OUT pin to the relay pin 1 (+).

Wire the relay pin 13 and pin 9 to the front panel PWR SW header pins.

As I have noted in other posts, I always wire up these circuits on the desk top using a dry cell battery pack for the +5 volts and ground just to ensure that I have identified the pins correctly and the circuit works as desired.

Good modding,
neil
 
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I'd like to follow these instructions (got the QT2010 and QT2012 now) but I don't understand how. How to I "tap into the pin 5 purple wire" or the PSU black wire? I've got a PicoPSU like this. What are 5V header pins on the motherboard? Pins on the USB headers? Or of the fan headers? My Mobo is a GA-Z270N-Wifi.
 

neilhart

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Sorry for not keeping current.

When using a device like the Mini-box picoPSU your options are to use a short extender cable to gain access to the purple wire (stand-by 5VDC power) and one of the black wires (ground), or if you are skilled with soldering you can just tack wires to the needed pins on the picoPSU.

Also there are 24 pin 90 degree adapters (male to female) the could provide access to 5VDC standby power.

Good Modding,
neil
 
Joined
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Messages
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"short extender cable" <- is this something I can just buy online? I mean I know what a PSU extender cable is but aren't we talking about something like a splitter here? Actually I don't know what to search for.

EDIT: Oh, about the 5V standby power. Is that something I could use the USB headers for? As far as I know the LED header pins on modern motherboards have ground power too? Or was that 5V vs 12V? Problem is that my Z270N-Wifi doesn't have LED pins, but other motherboards from other manufacturers do. Should I therefore try to exchange my board?
 
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