We would like to remind you of this upcoming event. Monday Night Chat Date: Monday, November 1, 2004 Time: 7:00PM - 9:00PM PST (GMT-08:00) Monday Night Chat...
We would like to remind you of this upcoming event. Monday Night Chat Date: Monday, November 1, 2004 Time: 7:00PM - 9:00PM PST (GMT-08:00) Monday Night Chat...
SeattleRobotics@yahoo...
Nov 2, 2004 2:04 am
20897
Not the most scientific method, but it is often very easy to write software to output a number of different frequencies. Just step through them observing the...
Hi all, I am a high school student and have built a radio control lawnmower as a science project. I am using a Futaba R/C system and pwm to control 12V motors...
Dave, the trade off comes in two flavors: Switching losses and current ripple. Current ripple is the ebb and flow of current from the voltage switching from...
I have two 4W maxon 40mm F type motors, I am using these on a test robot platform for the magnetic compass sensor I am working on. I have a motor driver with...
I don't have the junkbots book here right now. I'm sorry, it's been months since I read it. I'm wondering if you had to buy components, how much do you think...
... It's pretty dang cheap - the most expensive thing will most likely be the batteries for the project. Some small, DC motors with direct-drive from the ...
Thanks, Dave, that helps. I can't get the line follower down in that range. Well, I could turn two of our current light sensors into a line follower, that...
Hi Ok, I'm driving two Pittman 8712's with an L298N H-Bridge at 24 volts. With locked-antiphase PWM at 50% duty cycle, I get: 10 kHz = .066 A 15 kHz = .056 A ...
You could detect a brownout by having the raw solar cell voltage go through a resistor divider run that output into a comparator. The other leg of the ...
David, I noticed this EXACT same issue with the L298N sign-mag...not getting motor motion until 50% duty. I am running at 20khz. I am using cheapie, ...
Hi Ted, I've used sign-magnitude PWM on several robots, with a PWM freqency of 120 Hz. The SM works fine at that fq, but the LAP is pretty rough, and eats the...
Yes, a MOSFET gate driver is just what you need. They typically take a 5V logic-level input, and output a 12-15V (depending on supply voltage) gate drive...
... [...] ... I don't think this is quite right. There *is* regenerative charging during the "dump the magnetic energy" period. If you are in a heavy...
In a legacy project I used 18200's with Clifton Precision motors and had an identical experience with different duty cycles between standard PWM and LAP that...
Many years ago, when starting out, this is precisely the behavior I saw in my robots. The solution, it turns out, is to not use the ENABLE line for PWM. Use...
Hi ... Any idea why? Did the standard PWM work properly at lower frequencies? That is what I've determined. Standard enable-pin driven PWM works fine at 120...
Again, I repeat, and who said data sheets examples are optimal? DON'T USE THE ENABLE LINE!!! Think about it: with LAP the H-Bridge is ALWAYS connected to the...
On Wed, 3 Nov 2004 06:52:09 -0800, "Larry Barello" <yahoo@...> ... I use sign-magnitude PWM on all my robots, but I do not ever pulse the enable pin. I...
Hi, David, ... [...] ... (Here's a digression on precision motion control that may be of interest.) Perhaps "the difference" is related to the application. In...
Hi Chuck, What an excellent digression/summation! Thanks! Kenneth once posted a method for doing a current-sense feedback hardware mod that allowed a direct...
3 intresting ideas have been presented to me recently that I would like to get feedback on and start a brainstorming session online. 1. Hedge trimming...
Good ideas. I will look into both the RFID idea, as well as the wireless mouse hacking. Thanks for the input! Scott ... running) ... components. ... sight....
A little late on this thread, but you could just de-tune a regular RF unit. I like the ones from Linx, Bruce at Rentron has 'em. All you would have to do is...
oh dear - I still don't think I understand this. Here is what I think I have read: For applications that need good position control and/or have low inductance...
I just got this official announcement from Parallax, so I thought I would pass it on. For those of you that like the Basic Stamp, Parallax is now offering a...
I would suggest a Pipe mounded in a drill press with Outer Diameter of your hole size. Then use mirror grinding grit (or sand) with water to do the actual...
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