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(...) When I built the PWM controller out of a PIC I gave it 100 speeds representing 0 - 100% width. So a speed of 50 is a 50% duty cycle signaal. The disadvantage of the Handiboard scheme is granularity. In particular I have found that for really (...) (28 years ago, 25-Feb-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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(...) OK. (...) The transmitter is basically a modulator made from two 555 timer chips. One timer does 200-1000 Hz (we use 500) while the other does 38 KHz. On a scope, the output looks somewhat like.. |||...||| |||...||| |||...||| | | | | | | | | | (...) (28 years ago, 25-Feb-97, to lugnet.robotics.handyboard)
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| | Re: IR collision avoidance
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Some comments and a few questions for Chris (...) We have "forward" and 45 degrees right". We wall hug to the right while you hug to the left. We ignore IR to left and use only the left contact switch for collisions (rare). (...) We had way too much (...) (28 years ago, 25-Feb-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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The Handyboard has a circuit (U7a, R4, C6) that generates a 38KHz signal. That drives an amplifier that then goes to J7, the IR LED output. If you hookup an IR LED to this jack (with a series resistor) then when you turn on TOC2 using ir_xmit_on() (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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| | Re: IR collision avoidance
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(...) I don't have the RS part numbers, but I bought them within the last few months so if there are "old" and "new" ones mine are probably "new". I checked out the RS web page and found that what they currently have is RS part number 276-137, and (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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| | IR Collision avoidance
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Chris or anyone who cares to respond, You put your message on the mailing list concerning the IR avoidance. I have a question about the hardware also. How are the leds powered? Are you pulsing them some way or what? I guess the decoder is what is (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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| | Re: IR collision avoidance
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This question seems to come up a lot here so I thought I'd post to the list rather than reply individually. Here's what I'm doing for IR collision avoidance. First, the hardware: I'm using 3 Radio Shack IR LED's in parallel and 3 Radio Shack IR (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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| | Using PD2 and PD3
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I am building the circuit that is in the mobile robots book on pg. 108 to turn on and off my IR led's. Is it best to use the bit_set to turn them on and off? Where is the best place to get the 5 volts I need for the 74o4 chip? How do you read the (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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| | Re: IR collision avoidance
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Hey Chris, Thanks for the ideas, one questiom?. Can you pass along the Radio Shack part numbers? It seems like there are older and newer RS parts out there, what are you using? JTW In your message you said: (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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| | Re: motor voltages
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(...) You can use diodes to drop the voltage but you need to attack the HB, cutting traces and so on. Depending on how you are mounting things, why not just use a lower voltage battery pack? Six Nicad cells give a nominal 7.2 volts, enough to drive (...) (28 years ago, 24-Feb-97, to lugnet.robotics.handyboard)
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