 | | Re: Re[2]: phone cord length
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(...) On the phone cord between the handy board and the charger/interface card, the signal voltage is TTL levels. There is also charge voltage, and ground in the other wires. RS232 level conversion is done by the MAX232 on this card. (28 years ago, 4-Mar-97, to lugnet.robotics.handyboard)
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| | Re[2]: phone cord length
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TTL does NOT go down that line, it is RS232 which is commonly used at up to 50 feet. However, you might need to use a shielded cable if you use a lead longer than about 10 feet. Richard (28 years ago, 4-Mar-97, to lugnet.robotics.handyboard)
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| | Re[4]: IR Collision avoidance
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Adam, I don't use -5v, I just use a single 5v supply. You have to choose your op-amp carefully - I am currently trying ICL7612 but I'm looking at another sort which might turn out to be better. With a single supply, you have to bias things around (...) (28 years ago, 4-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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The part number on the device from Radio Shack is "GP1U52X". In our earlier discussions, I thought I made it clear that I was using "the Radio Shack IR detector module", although I may not have quoted the number. If Sharp makes a module without the (...) (28 years ago, 4-Mar-97, to lugnet.robotics.handyboard)
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| | IR xmitter/receiver idea.
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Heres a IR xmitter/receiver idea for you; I've seen this approach used in equipment and it works very well, I'm not sure how well it will work for robotics but believe it can be adapted. This is difficult to explain but easy to build, so hang with (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | serial comm
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Good morning, I am building a handy board for the first time using the Douglas Electronics boards and parts from various sources. I have been following the assembly instructions to the letter but am now stuck at the end of section 4.4, Serial Line (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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Actually, I built the (...) This is exactly the same scheme I use. I'm using an IR module from Digi-key that has a side view, and five IR LED's spread around the front of the module at different angles. I have quite a few outputs, thanks to a little (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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(...) The Sharp IR modules are not being used to detect distance, they are being used simply as non-contact bumpers. This allows one to inexpensively put an arbitrarily long 'whisker' on your robot. The advantage to these things are that they are (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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At any point are you making an effort to detect your 40kHz IR signal? If you use the sharp IR detector to receive your 40kHz signal you are going to get an initial burst when the thing first turns on and then it will average out to zero just like (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: Re[2]: IR Collision avoidance
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(...) Richard, In my case there are two reasons. First, I'm not trying to find the actual distance. I just want to know if there is something within a particular range. I don't care if it's an inch away or a foot. The second reason is that I can get (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: phone cord length
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Hi Jeremy, I have used a cable as long as 25 feet to connect between the handyboard and the PC. It seems to work alright for me, but the technician at school warned me that wasn't a good idea because TTL runs across the cable, and that's a bit too (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: Re[2]: IR Collision avoidance
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Richard, I've tried the op-amp method and had some success. I just don't know how I would power the -5V via the HB. Do you have any suggestions? Thanks. (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re[2]: IR Collision avoidance
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Bill, Why is everyone using a digital device to try to detect the (analogue) distance to an object? Especially one with AGC, it makes no sense! I modulated the IR at 10KHz (high enough to be away from mains light flicker, but out of the way of the (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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Well, at risk of being branded a heretic, since you've brought up the issue of modulated IR, I'm going to throw out an observation I've made about the Radio Shack IR sensors which several other people on the mailing list have privately disagreed (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | phone cord length
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Hi, I was wondering how long a piece of cable you can put between the handboard and the serial interface and still have it work. If anyone has any experience with this please email me... thanks, -Jeremy ___...___ Jeremy Green jag@world.std.com (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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| | Re: IR Collision avoidance
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(...) I have a few questions for you. How did you combine the 38khz and 500hz signal. In a design that I am working on now I have two signals similar to yours and an enable signal running into a three input AND gate. I haven't built it yet but it (...) (28 years ago, 2-Mar-97, to lugnet.robotics.handyboard)
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| | motors
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Hi, Yes, that schematic posted by Prabal was exactly what I meant. I sent you the bmp anyway, Adam. David (28 years ago, 2-Mar-97, to lugnet.robotics.handyboard)
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| | Re: motor voltages
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Adam, I think David meant something like this: |---|<|---|<|---|<|---| M+ ----x x----(motor)---- |---|>|---|>|---|>|---| | | M- ---...--- That way you have a voltage drop AND conduction in both directions. - Prabal (...) (28 years ago, 2-Mar-97, to lugnet.robotics.handyboard)
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| | where to get a board.
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hello. i'm new to this mailing list, and would like to purchase a handy board. i'm curious if there i a place where i could perhaps find a used one (in working order), or who the best (read: cheapest) distributor is. thanks for info you can provide. (...) (28 years ago, 2-Mar-97, to lugnet.robotics.handyboard)
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| | Re: Servos and Handyboard.
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you can't power 2 servos from the hb's own +5v supply. get a separate 5v supply (linear regulated, *noT* a switching supply, OR batteries) and run your servo power from that. connect this external supply ground to the HB motor ground (on J13). -Fred (...) (28 years ago, 2-Mar-97, to lugnet.robotics.handyboard)
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