 | | bipolar steppers
|
|
Was wondering if anyone has an alternate solution to stepping a bipolar stepper? Currently.... I'm using an H-Bridge (driver if you will) SAA1042 (by Motorla) which is then getting its pulses from 1 of the motor outs on the Handy Board. The (...) (28 years ago, 23-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | RE: dual servo update
|
|
Mike writes : (...) The limit is specified by the product manufacturer. Futaba servos don't guarantee they will hold unless they see a pulse every 20mS. The Tower Hobbies servos are a bit more lenient. If you have the servo manufacturers data sheet, (...) (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | Re: LCD screen
|
|
(...) I ended up with a display that did this very thing (A Rolm display I think), and what I did was to cut the contrast lead coming out of the LED connector, and then solder a 20k pot to the GND, +5V, and Contrast leads so that I could vary the (...) (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | Re: LCD screen
|
|
Garth The contrast of the LCD can be adjusted. The third pin from the left side of the LCD, labeled VR on the HB is the contrast adjustment. You can cut this pin from the male header than connects to the HB. Solder a small trimmer pot with the wiper (...) (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | Re: LCD screen
|
|
I have seen cases where an LCD display was destroyed by excessive heat. I used to be in a car rallye club, and we had several timers destroyed by being left in a hot car. Could your board have been exposed to high temperatures during your travels? (...) (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | Handy board use in Micromouse
|
|
Hello, I am new to this group, so I may be repeating previously answered question. I wanted to know if anyone has looked into using the handyboard for building a Micromouse. Comments on their experiences and ideas would be appreciated. Tejesh (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | LCD screen
|
|
After turning on my handy board after some traveling with it (and loading IC, etc) I have found that the contrast of the screen is very high. If looked at straight on the screen looks black (well, all black squares), but if looked at from an angle, (...) (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | RE: dual servo update
|
|
(...) I send my servos commands every 32.768 mS, and they work fine. I don't know what the limit is, but I don't think that 20 mS (50 Hz) is critical. * Michael L. Ross/C33 | Lockheed Martin Eng & Sci Svcs Co. **** * Robotics Department | 2400 Nasa (...) (28 years ago, 22-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | Sharp IS1U60
|
|
hi everyone, i bought 8 sharp IS1U60 IR detectors from Sterling Electronics.. (refernce "mobile robotics-inspiration to implementation) They have a $25 minimum purchase, the parts are reliable and are still working well for me. They cost $3.25 a (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | dual servos
|
|
Good Day, A consensus seems to be emerging among those who know more about pcode interrupt structure than I. The printf function does indeed disable the interrupts and run that way for quite a long time. Thus, the servo twitching seems to be mostly (...) (28 years ago, 21-Jan-97, to lugnet.robotics.handyboard)
|
| |
| | Re: Twitchy servos
|
|
(...) 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)
|
| |
| | MEMORY FAULT
|
|
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)
|
| |
| | RE: dual servo update
|
|
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)
|
| |
| | Stepper Motors driving [DAT]
|
|
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)
|
| |
| | Re: IR Demodulator
|
|
(...) 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)
|
| |
| | 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)
|
