🚀 go-pugleaf

In <Bz9n8u.Ir5@ssesco.com> elmquist@pez.ssesco.com (Chris Elmquist) writes:

>This may have been discussed here recently... if so, perhaps someone
>can point me to the archive.

>What's involved in building a wired IR repeater ? (to control equipment
>inside a closed cabinet for example).  Is there more to it than just
>a receiver, amp, and transmitter LED ?  I seem to remember some discussion
>where a 555 timer was being used (to re-time perhaps ?)

>Does anyone have a circuit for such a beast ?  I know where to buy them
>(for $50+) but I'm interested in integrating a homebrew circuit...

I built a point-to-point infrared repeater for my house using the
Radio Shack IR receiver/demodulator (it costs about $3.50).

Use the little, silver cube.  Most all remotes today use the 40khz
carrier and work fine with the setup.

When using the cube remember two important things: ground the cube's
metal shell! (cost me a few hours debugging to the erratic behavior
with an open shield) and the data sheet lies.  The biggest lie is
the output waveform.  On my data sheet, it shows a positive logic
waveform.  It is actually inverted.  Also, the data sheet gives
no specs on the output signal (volts/current draw) at all.

I built the receiver (cube, 2N2222 to drive the line, and an led
for feedback) in an RS-232 shell on a wire-wrap 14-pin socket.  I
connected a three wire (+5v, gnd, and signal) to the receiver and
ran it back to the transmitter/power supply next to my equipment.

I used the diagram on the back of the cube's data sheet to build
the remodulator.  (The RC used for the 555 varies depending on
who made the 555.  Don't trust the sheet.  Walk through the timing
calculations for the 555 you buy.)  The signal line turns the
555 running at 40khz on and off (modulates) it recreating the
original signal.

If you have access to a 'scope, buy an IR photo-transistor for
debugging.  I also found the radio shack IR detector card useful
too. 

If you want more detail, let me know.

>Thanks.

>Chris


>--
>Chris Elmquist, N0JCF
>elmquist@SSESCO.com
>73267.2711@Compuserve.com
>(612)342-0003@work (8am-5pm CST6CDT)
-- 
Quentin Barnes
qbarnes@urbana.mcd.mot.com | ..!uiucuxc!udc!qbarnes