From: Blars B. <bl...@bl...> - 2002-10-06 20:41:31
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Schematic at http://www.blars.org/blarslirc/blarslirc.ps or http://www.blars.org/blarslirc/blarslirc.jpg . (The .ps is smaller.) D1-D3 TSAL6400 D4-D7 1N4148 Q1 2N4401 Q2 2N3904 R1 10 R2 4K7 R3 10K R4 10K R5 1K R6 1K C1 4700uF,16V CONN1 DB9F Notes: D1-D3 can be almost any infrared LED. TSAL6200 would give better range with more critical aiming. A visible led can be used for one of these if you want an indicator. Resistors are 1/4W. (Smaller than 1/10W are hard to work with.) I use 1% because they are cheap. R1 controls the LED current. It will have about 650mV when the circuit is on, so 65mA is expected with 10 ohms. For better range, you might try 6.8 ohms. If you have problems with repeated commands, try 22 ohms. Q1 should have good hfe at 65mA Ic, and be able to dissipate several hundred milliwatts for short periods of time. Q2 is less critical and used at lower current. A 2N4401 would work fine here. C1 will take about a minute to fully charge. All parts are available at www.newark.com, but they overcharge for the connector. The other parts total about US $2.50. (Use MCR16V478M16X26 for C1.) This should work with a traditional 12V 1488 totem-pole serial port, may work with a MAX232 style port, (try R1 at 22 ohms) and won't work with a 5V cheat-and-pray port. -- Blars Blarson bl...@bl... http://www.blars.org/blars.html "Text is a way we cheat time." -- Patrick Nielsen Hayden |