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 | | re: IR frequency
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| How do i find out the frequency of the IR signal emanating from the LED? Just by connecting the leads from the LED to a CRO ? (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
| | | | | Digital Outputs
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| I'm interested in finding more on how I might digitally controll more devices from the HB. From my current knowledge I was thinking it is possible (with some asm code) to drive TTL signals to the unused expansion header via A12 and A13 pins of the (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
| | | | | Re: IR for bots
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| Hi Richard, I believe 50% duty cycle of on/off time is just an arbitary number which is easy to implement. You can change to any other number or even can be some sort of coding at the rate that is less than center freq. or carrier (38Khz here). (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
| | | | | Re: IR for bots
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| (...) If you don't modulate the signal you run the risk of having another 40kHz signal (a.k.a. remoth control) trigger the reciever. If you modulate it and look only for you modulation code, then the chances of a stray signal are minimal. I have (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
| | | | | Re: IR for bots
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| (...) Our robot worked well with a dual 555 timer. 38KHz for the IR and combined with a 500 Hz square wave. When the square wave was high, 38K was on, making it a 50% duty cycle transmission. As I understand the receiver circuitry, it was tuned to (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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