Product Details - UIRT2B internal version



2 IR emitter jacks on PCB

PCB is designed with two jacks to connect two sets of external IR emitters. Each jack accepts a plug with two emitters on the end.  The values of R5 and R6 need to be determined depending on which and how many you use. Important: none of the 2 jack connections is grounded, so I decided to use a stereo jack and use the pin and ring for the actual connections

1 IR receiver jack on PCB

The PCB has a stereo jack to connect the IR receiver. The UIRT2  is designed to work with the receiver that is supplied with the kit and assembled unit. Other types of receivers may be used but may require modifying a resistor and zener diode on the PCB and possibly the plug.

4 buffered output ports controllable by Girder.

The buffered outputs can be used controlled by Girder and also by the PIC when the PC is powered down. 4 IR codes can be stored in the PIC and the corresponding output can be pulsed, toggled ,set high or low. This is how UIRT2 powers up the PC through WOL, WOM or the power button connector. The PC can also be reset by connecting one of these outputs to the reset.

LED's or relays can also be connected to these outputs. When doing this and you want to use the 5VSB to power these devices make sure that the PC power supply has enough 5VSB power left. It's better to use another supply like the regular 5 or 12v from the power supply. Also when using inductive loads there needs to be a clamping diode connected over the load to protect the darlington chip. button.

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..

Power-up PC via WOL (Wake On Lan)

The PC can be powered up by using one of the four PIC internal programmable IR codes. WOL requires a positive pulse on the input so a the PIC I/O pin (RB2) is used because it is low after reset. Using a buffer transistor would invert this and pull the WOL input high which might cause problems. A 3k3 series resistor is provided to protect both the PIC and the motherboard in case of incorrect connections. When using WOL the OUT4 output can no longer be used as it uses the same RB2 pin.

Trigger Girder command via hardware 

UIRT2 has a circuit that when closed send a preprogrammed IR command to Girder.

UIRT2 power supplied by WOL connector

UIRT2 is designed to get power from the WOL connector on the motherboard. If your MB doesn't have this or it's in use already, you can take +5VSB from other locations like the Wake On Modem header.

In Circuit Serial Programming

The recommended ICSP software is written by Daniel Pticar. The recommended  firmware is version 1.7 from Jon Rhees. Note there are different firmware versions depending on the crystal used (4MHz, 10MHz).


Circuit Simplification

If some features are not required the following components can be omitted:


PCB Layout

Component Layout


PCB Schematic

Schematic is in PDF format. Click here to view.


PCB Layout

Dimensions:1.250" x 2.575" (31.7x 65 mm) measured on the outline box (not from the outside tracks)

PDF    Postscript    PCL5