Re: Urgent - Time to kill, want to build IR Extender

["Graham Howe" <graham@xxxxxxx>]

Maplin part numbers for Nigel's transmitter:
555 Timer - QH66W
Transistors - QB31J (x 2)
Capacitor (0.01uF) - RA44X
Capacitor (120pF) - WX57M
Capacitor (47uF) - WW76H
Infra Red LED - CY88V
Red LED - NP04E

I didn't bother writing down the resistor numbers as I just asked for them
by description.

I have not tested this yet, so give no guarantees that all the parts are
correct, but these are the ones I have.

Regards

Graham
----- Original Message -----
From: "Ian" <I.Bird@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Tuesday, October 31, 2000 10:27 AM
Subject: RE: [ukha_d] Urgent - Time to kill, want to build IR Extender


> Yep - more gory details the better as I have promising to have a go at
this
> myself in the near future.
>
> Graham - if you have the M****n numbers handy for the parts you used I
would
> appreciate them as I have to mail order everything. As has been noted
the
> latest catalogue is not the best in the world.
>
> Thanks
>
> Ian
>
> -----Original Message-----
> From: Nigel Orr [mailto:nigel@xxxxxxx]
> Sent: 31 October 2000 08:24
> To: ukha_d@xxxxxxx
> Subject: Re: [ukha_d] Urgent - Time to kill, want to build IR Extender
>
>
> At 18:33 30/10/00 +0000, you wrote:
> >few questions (all of you electronics experts can feel free to
laugh at
my
> >stupidity!).
>
> I won't be laughing, at least not until I correct the schematic with
that
> stupid error of missing out the +12V connection :-)
>
> >First off, the 555 timer has an indentation on the top, does this
indicate
> >pin 8, also are pin numbers ordered as per Nigel's diagram, if not
what
is
> >the sequence.
>
> ICs usually look like
>
> 8  7  6  5
>
> i  i  i  i
>
> o
> i  i  i  i
>
> 1  2  3  4
>
> Where i are pins,  is a bar sometimes marked at one end, and o is a
dot
or
> dent which marks pin 1.  That's fairly consistent for almost all ICs. 
The
> 'o' at pin 4 on the schematic represents an inverted input, which
means
> that it is reset when the input is low, it's got nothing to do with
the
> package markings.  Sometimes the same thing would be shown as an R
with a
> bar over the top of the letter- just depends on the schematic drawing
> package.
>
> >Second, the LED's, I know that the shortest leg is the cathode,
does that
> >mean the other leg is the one to connect to the +12V.
>
> Probably.  Some LEDs are the other way round, there's no particularly
> common standard, if you can see inside, it looks a bit like a wire
going
> into a 'cup'.  The 'cup' is usually the cathode (I think, I usually
just
> test them with a battery!).
>
> Best way to check is to put an ordinary visible LED in series, with a
9V
> battery and a 1k resistor, then swap their direction round until the
> visible one lights- at that point, both anodes are towards the +
> connection.  If you have a CCD camera or camcorder, you don't need the
> visible LED, as you can 'see' when the IR one is on.
>
> >Third, the transistors, how do I know which leg is which. I have
assumed
> the
> >diagram shows the plan view of the transistor, but there is a
little tag
by
> >one leg which I have assumed is number three on the diagram, is
this
> correct
> >?
>
> Usually, though again not definitely, emitter (1 on the diagram) is
nearest
> to the tag.  If you have a multimeter with a diode test setting, it's
> possible to check the other pins, let me know if you want to know how.
The
> diagram is just a standard schematic layout, it might not correspond
to
the
> physical layout of the transistor you have.
>
> The Maplin catalogue usually has package pinouts for transistors,
check
> whether it is shown as 'view from above' or 'view from below'.  Where
the
> transistor is listed in the catalogue, it will say package type,
something
> like 'TO92', at the start of the transistors section there is usually
a
> page showing all the different packages and pins.
>
> Pin 3 on my diagram is collector (C), 2 is base (B), 1 is emitter (E).
 If
> that doesn't make sense, send me an email with the details of the
> transistor you have and I'll try to give more specific directions.
>
> >Finally, is there any way I can test the transmitter without a
receiver
and
> >when I get a receiver (hopefully from Keith), where does that
connect to
> the
> >transmitter ?
>
> There are 2 lines sticking out to the left of the diagram, with some
stuff
> about 'input' on them.  The lower one connects to the receiver's 0V
> connection, the other to the receivers output connection.  The
receiver's
> 3rd pin needs to be connected to +5V +/- 0.25V.
>
> The only way to test before the receiver arrives is using an
oscilloscope,
> a multimeter with a frequency meter, or a camcorder/camera.  If you
have
> any of those, let me know and I'll tell you what you can use it for.
>
> >I am sorry for these really basic questions, but this is my first
ever
> >circuit and I would rather it didn't go bang as soon as I connect
the
> power.
>
> Where's the fun in that   :-)  ?  I'm happy to try to help you get it
> sorted, feel free to email me directly if there are any more
questions-
> unless others on the list want to see more gory details?
>
> Nigel
>
>
>
>
>
>
>
>
>
>
>
>


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