View Full Version : Using simulated power-on from UIRT2B

April 7th, 2004, 03:58 PM

I need to be able to turn on my HTPC from hibernation mode.

I understand it is possible to connect UIRT2B to the power-switch connector on the MB so UIRT2B kan simulate power-on clicked and start the computer.

I have two questions:

1) How can you have both the regular power-switch AND UIRT2B connected to the power-switch connector? (if it is at all possible)

2) Can you program UIRT2B to only respond (and power-on) to a specific IR code?

January 15th, 2005, 08:10 PM

i'm having the same problem.
actually, i built uirt2 is to power up my pc with rem-control.
my mobo has no WOL or WOR headers, the only method i can power up my pc is thru ATX power-on header (which has 2 pins:+5V and ground).

according to uirt2 web:

Power-up PC via IR command
One of the UIRT2 outputs can be used to trigger the PC power button. A dedicated IR code is programmed into the PIC and when triggered, the PC power button is activated as if the button was physically pressed. This requires a connection to the "+" of the power button pin on the mother board. Before using this feature verify that the power button shorts it's + pin to ground. Not all motherboards are configured like this, so be careful to avoid damaging it..
~~end quoted~~

my questions:
1. what is the output should the power-on header be connected?
-WOL connector at uirt2 has 3 pins: +5V, Ground, and wakeup signal

2. the uirt2 need standby current when the pc is off.
i was adviced to use usb-root-hub to supply the +5VSB.
but it is troublesome to have another usb connector on the pcb. can +5V of power-on header supply the standby power to the pcb??

could anyone help??

sorry if this sounds stupid.



January 16th, 2005, 02:45 AM

i read thru old posts. i got some clues about the power-up connection for uirt2A:

1. connect "+5V" of power header to "output 4" (ULN pin#16)
2. connect "Ground" of power header to "ground" of "WOL" connector

my mobo support WOR feature, to get this works:
1. connect pin#9(RI) to WOL signal of WOL connector

correct me if i'm wrong.


January 16th, 2005, 12:32 PM
It's extremely dificult to answer these questions as every motherboard is different for the power switch, WOR, +5VSB supply etc...
The ONLY standard is the WOL connector (done by Intel) and that's why I used it.
If you don't have good electronic skills or don't want to mess up the MB then use a small relay driven by the UIRT2 and place the relay contacts in parrallel with the power switch.
There is a brief example for a relay but it is probably not clear for everybody, I just tried to explain the possibilities so that options can be used, see here:

I'll try to explain in more detail:
you need a small 12V relay.
Supply Ext. power with +12V.
Connect the coil to an out+ and out- as shown (doesn't matter wich one), diode direction is important.
Place a wire iso the R10, R11 or R13 depending on the chosen out.
You should now be able to activate the relay using Girder and UIRT plugin.
Connect the contact of the relay in parrallel with the powerswitch.
Now follow the same procedure to program the uirt for WOL but use the RB selection wich corresponds with the used out for the relay.

Hope this helps a bit.

You will need to get the +5VSB from "somewhere".
Here I can't help, it really depends on the motherboard.
Look through it's documentation, possibilities where you could find it are:
- a pin of the frontpanel header for switches and led's
- internal unused headers (USB, WOR..)
- you could also tap into the ATX wires to the motherboard.

"Legal stuff": Don't blame me if you're doing something wrong with smoke results... :)

January 17th, 2005, 02:36 AM

TQ for reply.

for +5VSB, i can try many possible source as u listed. i dun think this is a problem for me.

as for power-up feature, the only i'll use is the power-on header even though it's risky as u warned.
infact, i want to reduce wirings from pc to uirt2a (12V for relay need extra wiring:().

u adviced to confirm "+ pin short to ground" first, i checked with multimeter the voltage across + pin and ground pin of the header, it is about 3.5V at hibernate mode.
this means it shorted to ground, rite?

BTW, as u r one of the moderator of this forum, could u made some important threads as sticky? it helps to find answers for FAQ.



January 17th, 2005, 10:13 AM
I see you have UIRT2A and understand why you want to limit the wiring.
If you are sure about your measurements : the other pin should be real ground.You can verify this by measuring in ohms versus ground while the system is completely power off: power plug unplugged.

Then you can use one of the additional outputs and connect that to the + of the power switch, if you program the PIC to pulse that output the ULN will short the power switch.

If you want to play safe, you can also run that wire to the PC and mount the relay inside the PC, then you still only need the out wire.


Use a 5V relay iso 12V and supply 5VSB iso 12V to the ext. power: if the system is powered off there's only 5VSB....

January 19th, 2005, 06:51 AM

i have got it worked.

1. my mobo is asus p4p800 (no WOL/WOR headers).
2. uirt2 version is uirt2a.
3. +5VSB from "chassis intrusion connector"
4. connect "+" of power header to "output 4" (ULN pin#16) of uirt2a
5. connect "ground" of power header to "ground" of WOL

setting at PIC port pins (at "PIC config" tab):

1. program slot: 1
2. click "learn" to specify the IR code
3. GPIO: PortB.2
4. pulse/antirepeat: 500ms
5. "pulse" signal
(final step: click "program flash")

the ir signal transmited to my yamaha receiver (RX-V450) is working too.

i'm using firmware ver 1.7.

i'm happy :lol:

TQ again.


March 6th, 2005, 08:45 PM
...i have made a UIRT2 ( http://www.fukushima.us/UIRT2/)

from the product details i read:

"Power-up PC via IR command

One of the UIRT2 outputs can be used to trigger the PC power button. A dedicated IR code is programmed into the PIC and when triggered, the PC power button is activated as if the button was physically pressed......

..I have to set IR code to power up the PC...how can i do?

There is an utility?...a programm?

...please help me...

March 8th, 2005, 08:34 PM

I;ve not done it myself but the place where the software configuration is in Girder.

Create a new Girder command then go to plugins and select UIRT driver. You must already have the UIRT plugin installed. Click on settings and for action select modify PIC port pin.

The PIC config button takes you to a panel where you identify the hardware connections used to trigger the power on circuit.

RA0, RA1, RB1, RB2 are the external outputs, RB2 is shared between the WOL and Power contacts.

Hope this helps get you closer. Again, I've not personally used the GPIO so I don't have the exact procedure. Do post it if you get through it and I'll add it to the website.