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(...) all sensor inputs have a 47K pull-up resistor. If you remove this (by cutting the trace between the sensor input pin and the 47K resistor pack), then the analog inputs are pretty high impedence, like a meg or so. You should get the "M68HC11 (...) (28 years ago, 7-Jun-96, to lugnet.robotics.handyboard)
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Hi! Would you please let me know the input impedance of the AD circuit ? Thanks in advance. hajime (28 years ago, 7-Jun-96, to lugnet.robotics.handyboard)
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| | Re: your mail
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Yes, the h-bridge circuit is very, very, very confusing. Hmm. Well it's in my robot right now, so lemme see if I can remember how it works. Ok, let's see. First, you connect both of the emitters of the PNP power transistors to +6V or whatever. (...) (28 years ago, 6-Jun-96, to lugnet.robotics.handyboard)
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I'm having a little truoble with the H-Bridge described in this mailgroup. I have MOST of the circuit OK.. The power bridge itself, Diodes, etc.. I am also OK with the optocouplers to 2n2907s.. I am just a bit confused with the description if the (...) (28 years ago, 6-Jun-96, to lugnet.robotics.handyboard)
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| | Serial IO
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Yesterday I experimented with the Serial IO code in the FAQ. I have a couple of questions though. Here is the basic program that I wrote to try to understand this stuff: I wrote this into hb_lib.c: void disable_pcode_serial() /* necessary to receive (...) (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | Re: Question on analog()....
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(...) Right; a voltage divider probably biases the microphone amp ckt at 2.5v. schematics are provided, no? -F (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | Re:Re: Question on analog()....
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(...) Are you sure about this? On page 49 of my copy, it states pretty clearly that the input range is 0 to 5 v. ---...--- Just returned home. I checked the IC Manual of "The Mobile robot Assembly Guide" for the Rug Warrior. On p.66, it reads "When (...) (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | Re: Question on analog(). Negative voltage
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(...) DO NOT SEND NEGATIVE VOLTAGES INTO THE 6811, you will destroy the analog input circuit. Any voltage outside of the 0 to 5 v range is hazardous, unless it is current-limited to a few milliamps. (...) Are you sure about this? On page 49 of my (...) (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | Question on analog(). Negative voltage
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Last time, I learned that the values of analog() corresponds to the voltage between 0 and 5. What if the signal to the analog port is a negative voltage. For example, -2 volt ? In that case, does that mean I have to use another formula or make some (...) (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | encoders??
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Let's see. First, I'd like to put a pair, if possible, of shaft encoders on my robot. (It's annoying not being able to tell how far I've gone!) Anyways, digital inputs 7 and 9 are being used by a 6500 Polaroid sensor and an RC servo. Is it still (...) (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | Strange question
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Has anyone here used Electronic Workbench ? I've got a copy but it doesn't have schematics/models for the darlingtons (TIP120, 125, etc) I'm looking for spice models and ideally an symbol library. (yes it is for simulating various power control (...) (28 years ago, 5-Jun-96, to lugnet.robotics.handyboard)
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| | Re: voltage/current monitors
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(...) Use a voltage divider (two resistors) to map the battery voltage to a 0 - 5v signal for the A/D converter. Depending on how much current your motors draw, you can put a .1 ohm precision resistor in series with the motor and measure the voltage (...) (28 years ago, 4-Jun-96, to lugnet.robotics.handyboard)
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| | voltage/current monitors
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I'm interested in building a voltage monitor circuit for my robot's 6V battery, and a current monitor circuit for the motors. Is there an easy way to do this, with reasonable accuracy? I'd like to interface both of them to the analog sensors on the (...) (28 years ago, 4-Jun-96, to lugnet.robotics.handyboard)
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| | Re: Yup, it works.
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The PWR light isn't really an indicator of power. It's actually hooked up to the 6811's serial transmit line, so it's supposed to flash when the 6811 is talking serial. the BATT light should always blink when the board is first switched on. It also (...) (28 years ago, 4-Jun-96, to lugnet.robotics.handyboard)
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Cris, I just built my HB last week, I can offer these comments.. The green power LED should flash while you are loading the board through the serial port. Actually, it's more of a flicker, it's just an indicator of serial activity. As far as the (...) (28 years ago, 4-Jun-96, to lugnet.robotics.handyboard)
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| | Re: Yup, it works.
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I didn't have any problems with the LED's - mine came with a short lead and that always went into the square pad. I imagine I missed the C15 and C16 errors (tantalum vs electrolytic) because I bought a kit and just took the parts out of the packages (...) (28 years ago, 4-Jun-96, to lugnet.robotics.handyboard)
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| | Success, sorta!
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My long-sought goal of bringing in 2 RC signals to the IC3 and IC2 counters, and sending them out via OC3 and OC2 was not achieved. I was never able to get OC2 to work, and I suspect I need new Pcode like what Randy Sargent wrote to use the buzzer (...) (28 years ago, 3-Jun-96, to lugnet.robotics.handyboard)
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| | Adapting the LMD18200
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Over the weekend I decided to use the LMD18200 H-Bridge devices for a larger robot I am building. What I did was simply remove the L293 chip and replace it with a 16pin header and some rainbow ribbon cable. Before you decide this is for you, here (...) (28 years ago, 3-Jun-96, to lugnet.robotics.handyboard)
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| | Re: Yup, it works.
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(...) I really tried hard to make this clear -- can you explain the difficulty you had? (...) Yup, you are right. You are either the first person to notice this, or the first to report it! (...) Quiescent RS-232 levels are -10v, so the minus voltage (...) (28 years ago, 3-Jun-96, to lugnet.robotics.handyboard)
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| | Yup, it works.
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Well after much delay, I've finally got my first HandyBoard up and running. (I've got another one in parts, but that is a different story) I can confirm that HBDL.exe does *NOT* work on my 133Mhz Pentium under Windows '95. It does work on my 486/33 (...) (28 years ago, 3-Jun-96, to lugnet.robotics.handyboard)
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