 | | 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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| | 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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| | Re: IR Subsystem confusions.(Never Mind)
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Oh never mind my questions. I read the other messages after this one and looked it up too. It now makes sense to me. Sorry. ---...--- ericson mar Master of Engineering Candidate Project: Mobile Robotics mar@cooper.edu (212)353-4356 Department of (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | Communicating through serial port
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Hi, I am trying to use the my handy board to communicate with an application on my computer by passing integers through the serial port. From my understanding, a binary subroutine must be called to access the serial port. Is this true? If so, why? (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Subsystem confusions.
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Does the HB have demodulationg circuitry? According to the diagrams, the Sharp IS1U60 is connected to TIC1 on the HC11. Does this mean that the HC11 is doing the demodulation? Is the Sharp IS1U60 an IR demodulator, or simply and IR receiver? I (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Subsystem confusions.
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(...) It is a useful for wireless communication (one way), beacon detection (the 6.270 boards used it for this) and for collision detection. (...) The part on the Handyboard has a 'center frequency' of 38Khz whereas the Radio Shack part has a center (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Subsystem confusions.
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In your message you said: (...) main purpose: allowing HB's to transmit IR codes that can be rec'd by other HB's or circuits. example -> let an HB run an IR beacon that can be found by another HB. sub-purpose: run IR transmitters for reflective IR (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Subsystem confusions.
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(...) The handyboard consists of an IR transmitter and detector circuits. The purpose of the transmitter (when connected thru the infrared LED) is to produce infrared light waves at particular frequencies. This frequency is controlled by R4 and C6 (...) (28 years ago, 28-Mar-97, to lugnet.robotics.handyboard)
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| | IR Subsystem confusions.
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What was/is the purpose of the IR Subsystem on the Handy board. What is the difference between the Sharp Demodulator and the one you get from Radio Shack. How do you use the onboard IR demodulator as a digital input. Are there different kinds of IR (...) (28 years ago, 27-Mar-97, to lugnet.robotics.handyboard)
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| | (no subject)
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Thanks for the information. By the way, does the LCD output work the same way the parallel port on a P.C. Does? On a P.C., I believe it outputs like this: 1) out the coding for the letter in 1's and 0's in 8 positions (binary) 2) a line (I believe (...) (28 years ago, 27-Mar-97, to lugnet.robotics.handyboard)
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| | Re: SPI port config???
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Hi Adam, I am not certain by poking the register 0x1009 (or DDRD reg) alone could provide the clean work. The function of this register is also depending on SPE bit in the register 0x1028 (or SPCR) according to the manual. I believe you could (...) (28 years ago, 27-Mar-97, to lugnet.robotics.handyboard)
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