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 Robotics / Handy Board / *1299 (-20)
  Re: dual servo update
 
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)
 
  Re: addendum
 
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)
 
  addendum
 
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)
 
  Re: IR Demodulator
 
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)
 
  dual servo update
 
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)
 
  IR Demodulator
 
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)
 
  Re: mosfet H-bridge
 
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)
 
  RE: mosfet H-bridge  [DAT]
 
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)
 
  mosfet H-bridge
 
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)
 
  Re: Sensors
 
(...) Voltage. (...) Yes. (28 years ago, 20-Jan-97, to lugnet.robotics.handyboard)
 
  More Sensors
 
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)
 
  Re: Robot Soccer Teams
 
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)
 
  Twitchy servos
 
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)
 
  Re: Ranging
 
(...) 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)
 
  Robot Soccer Teams
 
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)
 
  Re: dual servos
 
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)
 
  Sensors
 
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)
 
  RF communcations
 
--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)
 
  Re: (IR sensors)
 
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)
 
  dual servos unstable?
 
(...) 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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