 | | Re: Sonar Transducer Multiplexor
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(...) The OC is simply a protective buffer to the SPI pins. When the SPI feeds a low with a pullup resistor it must be able to sink the current drawn by the resistor. I read some of the docs on the SPI pinouts and ("M68HC11 Reference Manual" Serial (...) (28 years ago, 29-Mar-97, to lugnet.robotics.handyboard)
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| | Sonar Transducer Multiplexor
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In your BMP circuit diagram that you posted recently, why did you use an open collector to feed the base of the transistor? Would it work if you connected the digital signal directly to the base? ---...--- ericson mar Master of Engineering Candidate (...) (28 years ago, 29-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR concept
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(...) [Digitize the output from an IR LED with and without a signal present to achieve some common mode noise rejection.] This type of system is susceptible to being 'blinded' by high intensity IR sources (try it outside :-) I used a similar (...) (28 years ago, 29-Mar-97, to lugnet.robotics.handyboard)
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| | u14
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I had trouble finding u14(LM 2931Z-5.0). I thought I might be able to use the 78LO5A that was suggested as a replacement on the mini board. When I try to test the voltage on pin 28 of U2 as described in part 2 of the assembly manual I get 6.3 volts. (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR concept
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In addition.... Perhaps I could use the on board IR header to turn on the 4 IR diode array with each diode in series with a current limit resistor and in parallel with the IR output header..?? (I think this has been suggested before.) (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | IR concept
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An alternate IR system.... I've been scanning through some of the IR stuff to see if I can't pick out a good solid system for collision avoidance on a short range (approx. 6-10cm) scale, but everything seems like alot of trouble. Some guys at Humber (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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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)
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| | 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)
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| | 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)
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| | 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)
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