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chaumurky
December 11th, 2004, 11:23 PM
I would like to know people's opinions on the choice of enclosure for a home made uirt2. I've just finished one on vero board and apart from some noise issues it works reasonably well. Would housing the unit in a metal enclosure help reduce interference. Also, would sourcing the 5V power from and external plugpack adaptor help? I haven't added an L-C filter on the IR receiver yet - is it worth while? I think that's enough questions for now. Thanks for any help guys.

BTW, here's my layout for those interested.

TOP (http://carters.homeip.net/uirt/top.jpg)
BOTTOM (http://carters.homeip.net/uirt/bottom.jpg)

(The links on both sides are insulated but LochMaster couldn't show it).

danward79
December 12th, 2004, 05:35 AM
Hi,


Would housing the unit in a metal enclosure help reduce interference

Yes, especially if you ground the case right. But you should not need to do it...


Also, would sourcing the 5V power from and external plugpack adaptor help?

Yes, and no, is it a usb version? Perhaps the qulaity of the supply on the usb outout of your pc will be better than that of a wall unit? What ever you do use a decent supply.


I haven't added an L-C filter on the IR receiver yet - is it worth while?

Depends on the noise!

chaumurky
December 12th, 2004, 04:58 PM
OK firstly, it's the common serial version found at http://users.skynet.be/sky50985/ . At present, I'm only using the emitters from pin 11 of the PIC (pin 13 of the darlingon array). I'm getting the 5V from a spare floppy plug until I get the proper WOL micro connector and I'm using 2 core shielded cable for that. What I'm getting is a varying amout of supurious data when the IR receiver is connected, even in complete darkness (seen when running the test program in RAW mode). It's enough to make learning codes in Girder a little troublesome at times. It does vary though. Using 5V from the floppy plug of another computer had better results. It leads me to think that I'm getting electrical interference either from the power supply or EM from somewhere. What do you think?

danward79
December 12th, 2004, 05:05 PM
I would start with a metal enclosure well grounded

chaumurky
December 12th, 2004, 05:21 PM
OK, thanks. Would the ground from the power supply be OK or the serial ground - or doesn't it matter?

danward79
December 12th, 2004, 05:34 PM
I would use the psu ground

windtrader
December 19th, 2004, 10:36 PM
You need to add the ferrite cores to suppress the noise. This is certain. Initially, I had the same problem as you: crazy noise even in no light conditions during learning. The reduction in noise was very dramatic after addintg the cores.

If the receiver is located remotely then make sure to use shieled wire.

You can get to my UIRT2 site off Luc's or go directly to fukushima.us

chaumurky
December 20th, 2004, 04:57 PM
It's now mounted in a grounded aluminium case and the receiver has an LC filter. I'm now sourcing power from usb and it's still very stable. Thanks all for your help.