RE: I need some Help..

["Ian Lowe" <ian@xxxxxxx>]

Keith Wrote:

>Hi Ian,
>I looked at the original UIR many moons ago but never did anything with
it.

Same here. The UIR looked useful, but I really needed the UIR*T* to do what
I wanted..

>The sites you mention look to have some interesting stuff on there.
>Looking at the "Improved" design a few things spring to mind.
>
>1. The program the chip in circuit. Is this how you did it or do you
also
>have the means to program a PIC? If the hardware isnt working properly
there
>is no way you would be able to program the chip.

I am working from a newer schematic, which doesn't support SIC programming,
and uses an externally derived 5V Supply. I have a JDM PIC Programmer,
which
is working fine.

The Schematic is Here:
http://www.geocities.com/jon_rhees/UIRT/PCPoweredNoICSP.GIF
(sometimes, you need to go to http://www.geocities.com/jon_rhees/UIRT/
then
open the GIF)

>2. It is powered from the serial port. Have you checked the voltages on
the
>board are correct. Some serial ports will not supply sufficient current
to
>power it. I seem to remember that power was a big problem witht he
original
>design but you can always add a wallwart PSU to power it (with a 5V
>regulator of course).

I thought my issues were related to Power to start with. I am using a Drive
Power Splitter cable (of the sort used to power big CPU Coolers, swapped to
5V rather than 12V) it delivers a nice steady 5.02V to the Board.

>3. What OS are you using? I guess Win2K or WinXP. Is the software
compatable
>with those operating systems. Com Ports are funny things under NT/2K
(dont
>know about XP). Lots of software that runs fine under Win 9x will not
work
>on NT/2000.

I have a Dual-boot system, and have tested it in Win98 (I have to use 98
for
my PIC Programmer, for instance) THe Final Girder software with plug-in is
2K/XP compatible, however, the testing software is not.

>Is any part of it working ?

Nope. It doesn't *do* anything without talking to the host. I am thinking
my
problems are RS232 related, but can't think of a way to check this. I know
my Serial Port is OK, as the PIC Programmer works on it, (tested a modem on
it too) I'm not sure of the pinout for a 3-wire serial connection. I had to
make the leads on my PIC programmer *really* short to work, but I have
tried
very short leads with the UIRT, with no joy.

I don't even know PIC ASM (just couldn't get my head round it) to write up
a
noddy little HEx file to switch the IR LEds on and off at 2 second
intervals, or something like that..

>Are there "sample" IR files for transmission. If so, look at
the unit with
a
>CCD camera and you will see the IR LED's flash.

No, the "simple" side of the circuit is supposed to be the
Receiver side,
and that relies on Serial Comms..

One thing: I have not included the 2N2222 transistor, or the link to my
PC's
ATX Power Button. As i read the schematic, if the RA1 line is pulled high
by
code, this will provide the voltage required to turn this Transistor
"on"
which will pull the ATX_PWR button low, and toggle the PC's power state.
(or, the other way round, the line goes low, it will switch the transistor
off, allowing the ATX_PWR button to go high) I can see no reason that
leaving this section of the circuit out would cause the circuit to fail?

Another modification: I was not sure about the cap I had between V+ and GND
on the TSOP, so I removed it (shows as optional component on the schematic)
As instructed, if not using this optional component, I have jumpered out
the
47Ohm resistor.

John Tankard Wrote:

>What test equipment have you got ?

I have a digital Multimeter, which has an up to 1MHz frequency counter, and
all the usual stuff.

>What have you tested and where ?

in the schematic above, I have tested that I have a 5V Supply to the board,
that I have 5V between pins 14 and 5 on the PIC.
Around the TSOP1838, I have tested that: 1) I have a 5V Supply 2) I have a
good Ground 3) When I send an IR signal to the TSOP (using a VCR remote
control) I see the voltage on the Output pin (measured between Pin 5 and
Pin
9 on the PIC) change as expected.

My meter only goes to 1MHz, so I can't check the XTAL is runing correctly
at
4Mhz, but I certainly get an O/L reading between pins 15 and 16, suggetsing
to me that there's *something* there.

>Have you tried some _very_ simple code to tog RB4& RB5 and watched
to see
if you get and output.

I just don't know how to John :( is this a simple thing to do? If it's only
a few lines, and you could show me the structure, I'm sure I would pick it
up nice and fast!

>If you lived nearby you could borrow a scope to help check it out. As a
>last resort if you are _really_ stuck if you send it to me I will take
a
>look at it for you, but it could be a couple of weeks before I could
get
>to look at it

The offer is appreciated, and I might do that if I remain stuck, however I
would love to learn though this, and am really looking for a help up,
rather
than just bugging people!

Ian.



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