 | | Re: Twitchy servos
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(...) I'm using a 80C32 board and control two servos by generating a PWM signal with a timer interrupt. It frequently happens that the servos twitch. In my experience the period of 50 ms of the PWM signal was too great. The problem disappeared when (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | MEMORY FAULT
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When I turn my HB on I get the message "MEMORY FAULT" what does it mean and how do I fix it? Thanks, Peter Eacmen (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | RE: dual servo update
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Two things to note in the servo investigation: (...) This supplies a reserve of current to the servos, and that allows them to seek to their desired position faster. (...) Two servos, when moving, can pull two AMPS of current. Thats 2000mA. Two (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | Stepper Motors driving [DAT]
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Hi - I am new to this list but the archive indicates some interest in driving stepper motors on the HB so here is my little bit: If we have a typical four coil, unipolar stepper such as those found in disk drives, they will have connections (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | Re: IR Demodulator
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(...) I'll post this again: 4 sharp GP1U58Y: 40KHz IR Receivers for $12 From page (URL) them at mek-orders@orlandone...igital.net These are compatible with the IS1U60 as far as i know. I ordered 4 of them and they were shipped to me in the (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | Re: dual servo update
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Hi, I spent a bit of time a couple of months ago re-arranging a lot of the Pcode (we all get our kicks different ways!). At that time, I concluded that the printf routine (or more specifically the despooling function of the buffered characters going (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | Re: addendum
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Ahah. due to the arcane way printing to the lcd screen is implemented, all interrupts must be turned off each time a character is written to the lcd. apparently this conflicts with the servo routines. i'll look into it and see if there is a (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | addendum
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Hello again, I forgot to include the most interesting part of my findings. Removing printfs from my routines (which I did independently from all other fixes) markedly improved performance of the servos. This is actually one cause of trouble which I (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | Re: IR Demodulator
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I too am interested in getting the Sharp IS1U60 but have not been able to locate it. Scott sherman@plains.nodak.edu (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | dual servo update
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Hi, For any interested dual servo users the following is what I have been able to find regarding the twitching. Wiring a 1000microf electrolytic across the 6V within inches of each servo seems to work. However, a much more important fix has been (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | IR Demodulator
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Hello Everyone, I have had absolutely no luck in getting a IR Demodulator for my HB. I have tried every source given on this sight and even more. Can anyone help me to locate this part? Sharp (IS1U60) Having No Luck! Bill Rose (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
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| | Re: mosfet H-bridge
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I would also be interested in plans for such an H-Bridge. I have two 12Vdc motors than take 3.5 Amps at full load (actually gearhead motors so I get lots of torque @50 RPM) but they have surges us to 12 - 14 Amps at start-up and if they get stalled. (...) (28 years ago, 20-Jan-97, to lugnet.robotics.handyboard)
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| | RE: mosfet H-bridge [DAT]
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Sure, I've built several. The only "trick" to MOSFET bridges is that if you use all N-channel FETs you need a charge pump on the upper FETS. (look out for typos, this was done 'off the cuff' so to speak.) Chuck's Simple MOSFET Tutorial ---...--- (...) (28 years ago, 20-Jan-97, to lugnet.robotics.handyboard)
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| | mosfet H-bridge
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Hello, does anyone know how to build a mosfet hbrige and, if so, could they pass that on to me? It is my understanding that the mosfet hbridge does not heat up near as much as the transistor hbridge nor does it have any loss of voltage or current (...) (28 years ago, 20-Jan-97, to lugnet.robotics.handyboard)
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| | Re: Sensors
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(...) Voltage. (...) Yes. (28 years ago, 20-Jan-97, to lugnet.robotics.handyboard)
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| | More Sensors
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What is the smallest difference between voltages that the HB can differentiate between at its analogue inputs.I am very grateful for the information which has already been supplied in reponse to my queries and have found it useful though not (...) (28 years ago, 19-Jan-97, to lugnet.robotics.handyboard)
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| | Re: Robot Soccer Teams
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Perhaps someone can post it on their HomePage or something so that we all can read it. :) (...) (28 years ago, 19-Jan-97, to lugnet.robotics.handyboard)
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| | Twitchy servos
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Hi. I also have the problem of twitchy servos, but I am currently only using one of them. The servo is used in steering and it constantly twitches. Although, when I have nothing else hooked up to the board and have only the servo running, no twitch. (...) (28 years ago, 18-Jan-97, to lugnet.robotics.handyboard)
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| | Re: Ranging
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(...) The Polaroid sensor (50-60 KHz, 1.5-30 feet but maybe more from the air?) is $49 (minumum two) direct from Polaroid. They are in the FAQ or I can look up the ordering stuff if you are interested. There is plenty of documentation for using the (...) (28 years ago, 18-Jan-97, to lugnet.robotics.handyboard)
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| | Robot Soccer Teams
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I just read in Nuts & Volts about your triumph!! What an impressive feat! Doesn't it get boring having your robots beat the competition 15 to zip? Just kidding.. I can imagine the excitement you all must have felt to see your creation take off seem (...) (28 years ago, 18-Jan-97, to lugnet.robotics.handyboard)
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| | Re: dual servos
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Hi, Richard wrote: - but I just read yesterday on a web page that servos want a signal (20 ms = ?? degrees) every 50 milliseconds or so Right concept, wrong numbers. Servos want to see a pulse about once every 20ms. The pulse should be in the range (...) (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | Sensors
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Would someone be able to tell me whether the analogue inputs on the HB are sensitive only to voltage or to current.I would also like to know whether or not I could recieve sensor input on more than one analogue input simultaneously and make the HB (...) (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | RF communcations
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--text follows this line-- Check out the network section on (URL) the various options Thad Starner MIT Media Laboratory Wearable Computing Project (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | Re: (IR sensors)
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If you go to the following link: ftp://cher.media.mit.../cmcmanis/ You will find a file called ir.tar.Z which describes some software I wrote for a PIC chip that drove several LEDs and monitored three IR sensors (Sharp 1SU60s but could have as (...) (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | dual servos unstable?
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(...) Try running the two-servo code, but unplugging each of the two servos, in turn. One servo plugged in to the two servo code should narrow down whether this is a software or power problem. If it only jitters when both are plugged in, I'd (...) (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | dual servos
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Hello world, To richardv@abac.com, I am eagerly awaiting your results. To joe.doubek@privy.com, I'll keep you posted. So far I have gotten to the stage of pretty well ruling out input noise as the cause of twitching servos. I have almost identical (...) (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | Re: dual servos
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I'm a newbie at this, but I just read yesterday on a web page that servos want a signal (20 ms = ?? degrees) every 50 milliseconds or so, and if you stop sending the signal, they "go limp" and don't "hold" position tightly, but are deenergized and (...) (28 years ago, 17-Jan-97, to lugnet.robotics.handyboard)
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| | capacitor question
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I was just wondering about this - are you supposed to heatsink capacitors when soldering? My gut feeling says "no", except that my ECE TA seems to disagree. Any thoughts on this? (Sorry, this doesn't have too much to do with the handy board - (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | Re: power and servo
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[problem 1: voltage on motor chips when no motor voltage applied] This is normal, because the motor chip INPUTS have +5v signals on them. These signals "bleed" into the motor chip power supplies. This isn't dangerous, but it isn't particularly good (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | IR Demodulator
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Hello Everyone, I have had absolutely no luck in getting a IR Demodulator for my HB. I have tried every source given on this sight and even more. Can anyone help me to locate this part? Sharp (IS1U60) Having No Luck! Bill Rose (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | Re: (BrainDead)
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Dear Jim, In your IC distribution, there should a file called servo.lis. Make sure you have it, and add the following line to lib_hb.lis: servo.lis The *.lis files are kind of like include files, and will cause IC to load any files listed in them. (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | unsubscribe
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unsubscribe (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | unscribe
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Please unscribe "tdk@utrillo.wustl.edu" from the mailing list. Thanks. (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | HB ni-cad battery pack
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I located a 9.6 volt 700 or 900 mah battery pack at Radio Shack and the one on the parts list is just 500 mah. My question is, will the charging circuit work ok with either of the above battery packs from Radio Shack? Thanks Bill Rose (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | power and servo
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Hi everyone, I've got two problems that I hope your combined expertise can solve. 1) I cut the trace connecting the the motors to the main board supply, so that I could power them independently (as per the instructions I found on the web). The board (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | step motor interface & control
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For anyone interested in using step motors: I have found a way to use them - Pull out the L293's chips, replace the y6 clk signal on the motor latch with y4, then pokes to 0x6fff will allow you to send bit patterns for 2 unipolar 5 or 6 wire (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | Re: 100 sensors
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Joe, A very handy way to connect lots of digital switches is to arrange them in a resistor ladder and connect them into an analog input. You could get up to 8 switches into one input, giving you 256 different voltage levels, in theory, but in (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | Re: IR wall detection
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(...) Keith I think it works. I managed to get a bread boarded version of the IR sensor working. A 555 provides a 40khz carrier. The 555's reset pin is directly tied to pin 5 of a 567. The carrier is modulated by the internal freq of the 567. A (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | 100 sensors
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I am interested in sensing with about 100 water activated switches and am wondering if this is at all possible with the Handy Board.I had thought that it might be possible to by making them all return different levels of current at the sensor input (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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| | Re: LM629 and "quadriture incremental" encoders
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James, That's probalby my post you read. I'm still working on hooking 'em up. I'm gonna use two 629's and two 18200 H-bridges. The 629 uses encoders simmilar to the ones in mobile robots. The quadrature encoder has two signals that are 90 degrees (...) (28 years ago, 16-Jan-97, to lugnet.robotics.handyboard)
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