Common questions, problems, issues, concerns, etc. are answered here. If you still need more information, go to the UIRT Forum on the Girder Community Forums site.


Can you combine different frequency LEDs to the same wire, like 38 and 40khz?

    No, the LED's don't have a frequency. The UIRT2 drives the LED's at the carrier frequency you specify for the IR transmit command.

Is 38kHz the best starting point?

    Yes, unless you know the frequency of the remote you will be using, then it's better to use a matched receiver.

On the darlington outputs does 180 ohms provide high brightness and 330 provide low brightness?

    Yes,  for normal visible LEDs.

Do the darlington outputs send a pulsing signal like the IR LEDs?

No, it has nothing to do with IR transmission, the 3 outputs are controllable through Girder or with a dedicated (programmable) received IR code. In fact there are 4 outputs like this and one is used for the WOL/power switch. So you can control and setup the other 3 like you do for the WOL one, have a look at the PIC config in the plugin where you configure WOL. The outputs can be set to pulse, toggle, set on, and set off.

What is a clamping diode and what are typical specs for the diode and an associated +12V relay?

A clamping diode is required when switching inductive loads. At turn off, the EMF creates a high voltage peak that may destroy the ULN chip. Use a 1N4003 that is easily obtained.  The relay should have a coil resistance of 120 ohms or higher so the current through the ULN does not exceed 100mA on 12VDC.

I want to add receivers in different rooms. Can multiple IR receivers be added to the same wire or on a separate wire?

No. One receiver would pull on the others output and they could be damaged.

Are there alternatives to using ferrite core? Are there specs for the ferrite core?   I just ripped mine off an old analog modem card but found bigger ones on an old IR receiver board I had in the bin. Would a different cap work better?

You may try a 10 ohm resistor but the ferrite core is better. The kits now include salvaged ferrite cores and a 100n cap. The best cap is a ceramic type, it's better for filtering high frequencies than polyester types.

I would like to have the WOL feature on the LAN card work and use the UIRT2 WOL connection work too.  Do I just combine the wires together in series, parallel?

It could work, but they will pull each others output and damage is possible. Use the WOM connection or the PC power switch in this case.

What is In Circuit Serial Programming (ICSP )?

ICSP is used to program the firmware in an empty PIC so that the PIC can perform all functions for the UIRT2.
You need the firmware file (.HEX) wich contains the intelligence for the PIC.
Then you use a programmer to transfer the HEX file into the PIC.




1) Visit the Girder site for a lot of information on installing, configuring and troubleshooting GIrder.  Click here to go to the site www.girder.nl


WOL does not seem to work.

Make sure WOL is enabled and plug-ins are enabled on APM events in the BIOS settings.

Error "can't open commport" is caused by the "disable plug-ins on APM event".

WOL only works when the PC is shutdown. It doesn't recover either from Hibernate (preferred) or standby. These functions only work via the keyboard or power button.

I can't find a way to program the IR codes into the PIC?

When you create or edit a command: select UIRT2 driver under the Girder plug-in tab. On the pop-up window choose "PIC config", select "gpio b2" , choose "pulse", learn a IR command and press "program flash". It should work now. This is only for JON's plugin and is independent from the Girder version. The plug-in writes those codes in the PIC's data eeprom.

Pulse is required for WOL, I left the Pulse/Anti-Repeat time at the default 1.275mS.

LEDS are not wired correctly.

Ensure LED are wired correctly. The plug tip (+5v) is connected to the long leg and round side of the LED.

Girder receives different IR codes from the same button.

The supply to the IR detector on your UIRT is noisy. The IR detector is *very* sensitive to high-frequency noise causing it to output false signals when all is quiet -- when the detector's automatic gain control (AGC) is settling. To check if this is happening, create an event and press the 'IR DEBUG' button (below the 'Test' button) and *DO NOT* press any IR buttons. If there is noise, the progress bar will move, indicating you're receiving data, and you'll eventually see a screen full of random hex data. When in this IR debug mode, the UIRT outputs raw pulse data from the IR detector. Now, if you *DO* get noise, you'll commonly find that holding your hand over the IR detector to block all light will calm it down.  The best remedy for this problem is to put in an L-C filter on the 'supply' pin to the IR detector itself.

A small ferrite from a junk PCB can be used as the 'L' (L stands for inductor). Thru-hole ferrites on PC boards look like black, cylindrical resistors. They are basically a piece of solid wire running through a ferrite cylinder. What you would want to do is put one of these in SERIES with the V+ supply line going to IR detector. Then add a 0.1uF capacitor directly between the + and GND leads of the IR detector. Click here for picture.

IR receiver has low sensitivity.

Several receivers can be used such as the Vishay TSOP48xx, TSOP17xx, or Osram SFH5110. xx is the frequency designator. The 38kHz versions fall in the middle of the 36-40 kHz range used by most IR remotes. Experiment by orienting the receiver to get a good angle at the remote and free from other sources of interference.  

Girder: "cannot set com port speed"

It seems that there may be problems with the DTR/RTS signal on the serial cable. It seems related to timing errors between the PIC firmware and PC during Some have had success by running a 3 wire cable using just the RxD, TxD and GND. These are pins 2, 3, and 5.