Search found 31 matches

by Isenbergdoug
Tue Jan 20, 2004 4:06 pm
Forum: General Discussion
Topic: Permanent magnet motors...
Replies: 10
Views: 2154

Re: Permanent magnet motors...

The "stronger" magnets will cause the magnetic flux (phi) to change. This will cause a different torque to be seen given a specific armature current. The equation for this is; t=k*(phi)*Ia where t is torque Ia is armature current and k is the motor armature constant k=Na*p/(pi*a) where p is poles, N...
by Isenbergdoug
Fri Jan 16, 2004 6:36 pm
Forum: Computer Programming
Topic: pic c compilers
Replies: 3
Views: 2079

Re: pic c compilers

Thanks for the links, I never thought of using piclist to find out about C... it's great!
by Isenbergdoug
Thu Jan 15, 2004 6:43 pm
Forum: Computer Programming
Topic: pic c compilers
Replies: 3
Views: 2079

pic c compilers

I am looking for a c compiler for pics than handles the 14-bit parts. Most specifically I need to program 16f872's and 16f77's. My most important need is a good math library. By this I mean one that has sin, cos, tan, arcsin, arctan, arcos... which compute in radians, not the 0-255 range of the BS2 ...
by Isenbergdoug
Thu Jan 15, 2004 6:27 pm
Forum: Robotics
Topic: How PWM works?
Replies: 21
Views: 6610

Re: How PWM works?

Sunil, the physics is perhaps less important than the concept and idea. By varying the duty cycle, the time averaged amplitude is changed. Regardless of what is on the other end, if an o-scope is connected to a wire and a square wave is seen on the screen with a duty cycle of 50% with 5 V pk-pk, the...
by Isenbergdoug
Mon Jan 05, 2004 8:46 pm
Forum: Robotics
Topic: DC Motor speed control help
Replies: 8
Views: 3822

Re: DC Motor speed control help

'Al' is correct, if your motor is going to be driving a load, then the feedback can (should) be fed into a controller which then varies the duty cycle in order to maintain a constant speed. However, if you are just concerned with driving a motor at a constant speed with no load or a very light load ...
by Isenbergdoug
Sat Jan 03, 2004 8:33 pm
Forum: General Discussion
Topic: Schematic CAD program?
Replies: 10
Views: 2037

Re: Schematic CAD program?

There was a free version of 2-D Turbocad that may still be available on their web site. As far as schematic drawings, try the Orcad student version. http://www.orcad.com/downloads/demo/default.asp I use this software all the time not only for drawing schematics, but also flow charts and everything e...
by Isenbergdoug
Sat Jan 03, 2004 8:07 pm
Forum: Robotics
Topic: DC Motor speed control help
Replies: 8
Views: 3822

Re: DC Motor speed control help

Do you want to use feedback control (closed loop system) or keep it as an open-loop system (no sensor feedback)? Assuming a closed loop system, there are two ways to go about this problem, the hard way and the "hard" way. The hard way would be to derive transfer functions for the dynamics and the el...
by Isenbergdoug
Tue Nov 26, 2002 12:42 pm
Forum: General Discussion
Topic: Microphones
Replies: 9
Views: 2753

Re: Microphones

1 to 10 uf is a little to heavy. Without considering filtering, the capacitor is only blocking out the DC, so a small ceremic capacitor will work fine. In fact, feeding the signal through a .01 uf capcitor and pulling the side of the capacitor not connected to the microphone to ground with a 100k re...
by Isenbergdoug
Tue Sep 03, 2002 7:15 am
Forum: General Discussion
Topic: defective crystal
Replies: 3
Views: 1313

defective crystal

What are the chances that a crystal oscillator would be defective?
by Isenbergdoug
Mon Sep 02, 2002 5:23 pm
Forum: General Discussion
Topic: implementing finite state machines with PICs
Replies: 3
Views: 1271

Re: implementing finite state machines with PICs

I've reasoned it out. For applications where asynchronous aspects are required at low frequencies, the PIC will work fine. However, at high frequencies, this aspect may be better implemented on a traditional FSM. Additionally, the flow chart created for the FSM can be almost exactly implemented into...
by Isenbergdoug
Mon Sep 02, 2002 5:11 pm
Forum: Robotics
Topic: Just currious...
Replies: 20
Views: 6969

Re: Just currious...

Try this link, http://www.frc.ri.cmu.edu/~hpm/project.archive/robot.papers/1999/SciAm.scan.html I read the article a couple of years ago. Moravec derives the speed computers must run at to compare to a human, very interesting. One of his books is basically devoted to this, Robot Mere Machine to Tran...
by Isenbergdoug
Sun Aug 18, 2002 6:11 pm
Forum: General Discussion
Topic: Parabolic Microphone
Replies: 13
Views: 2645

Re: Parabolic Microphone

Edmund Scientific sells parabolic reflectors, here is a link to my first search under "parabolic". http://www.scientificsonline.com/Products/Search.cfm?SearchQuery_Required=Please+enter+a+search+query&query=parabolic+ <p>Satellite dishes should still be parabolic, or fairly close to it unless they'v...
by Isenbergdoug
Sun Aug 11, 2002 6:14 pm
Forum: General Discussion
Topic: implementing finite state machines with PICs
Replies: 3
Views: 1271

implementing finite state machines with PICs

Does anybody have any general tips or experience doing this, or ideas for directly going from a Moore or Mealy machine diagram or flowchart to a programming flowchart? <p>Douglas
by Isenbergdoug
Sun Aug 11, 2002 5:58 pm
Forum: General Discussion
Topic: dusk switch adjustable sensitivity...
Replies: 8
Views: 1729

Re: dusk switch adjustable sensitivity...

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">code:</font><hr><pre> <pre><p>+12 0---/\/\---o---/\/\---0 GND CdS | Var. Res. | | --------- \ / \ / Schmitt trigger inverter +12 0----\ /----0 GND \_/ (_) | | |_________/\/\______ |b NPN __|__ +12 o_____/ \___|-------| c e |your | |dev...
by Isenbergdoug
Sun Aug 11, 2002 10:00 am
Forum: General Discussion
Topic: Need some basic stamp II help
Replies: 2
Views: 1059

Re: Need some basic stamp II help

All you really need is the BSII pinout. I have THE BSII carrier board, and it really isn't anything more than a protoboard with the programming port on it. So to build a carrier board, connect;<p>pin 1 of BSII to pin 2 of serial port (TX) pin 2 of BSII to pin 3 of serial port (RX) pin 3 of BSII to p...