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Subject: 
RCX IR Tx Circuit
Newsgroups: 
lugnet.robotics, lugnet.robotics.rcx
Followup-To: 
lugnet.robotics.rcx
Date: 
Thu, 20 Jan 2005 21:02:16 GMT
Viewed: 
6748 times
  
Here’s my drawing of the RCX IR transmission circuit (receiver circuit to follow soon):



With the voltages as shown, the RCX is not transmitting.

The IR LEDs are powered by a 600mA current sink.

I haven’t measured for waveforms yet - the intermediate voltages may be averages of pulse trains. The lower transistor input from the processor is turned off by being pulled up towards +5V (PNP transistors require a low voltage on the base to turn on)

The CDC transistor has a gain (hfe) of 250, hence the -25 suffix.

This circuit was a bit more difficult since so many tracks seem to go straight to the processor. If I can glean any more from the H8 data sheet, I’ll add it later.

Mark



Message has 1 Reply:
  Re: RCX IR Tx Circuit
 
(...) Thanks for all your work on this Mark! It is very interesting, even for someone like me with only basic knowledge of electronics. Are you planning to put it all together on a web page some day? ROSCO (19 years ago, 20-Jan-05, to lugnet.robotics.rcx, FTX)

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