PDA

View Full Version : Monitoring RPM of Servo



jblaven
06-09-2005, 09:34 PM
Hey,

With the Boe-Bot, I would like to monitor the wheel/servo rpm.· With the whiskers on, the bot can still bump into things that are below the whiskers.· When this happens, the·wheels·bog/slow down.

Is there a way to monitor these servos through the basic stamp using the current circuit design?

I want to shine·a light through the open holes in the wheel to gauge the change in RPM and·to tell the stamp that it is·up against something.·http://forums.parallax.com/images/smilies/roll.gif

I have not added the infrared circuit to the bot, but could see how this would prevent·this sort of problem.· Even with infrared, I am guessing there are situations where the bot still may "bog" down.·

Watching the RPMs could help the bot know when it is trying to go somewhere it can't.· Can this be solved with code in the current circuit?

Any ideas or comments are appreciated!

Thanks,

Joe

Chris Savage
06-09-2005, 10:02 PM
Joe,

·· We have a Digital Encoder Kit for the BOE-Bot which could help you with this very thing...It can sense the speed of the wheels, as well as whether or not they're turning.· Might be an option for you...

http://www.parallax.com/detail.asp?product_id=28107



▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)

Bean
06-09-2005, 10:09 PM
Another trickier (is that word) way is to monitor the amount of current the servo uses. If the bot is "stuck" the current will go way up. There are current sense ICs that are made for this.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

Product web site: www.sxvm.com (http://www.sxvm.com)

"If you keep doing what you always did, you'll keep getting what you always got."
·

Jonathan
06-09-2005, 10:17 PM
Joe,

I've been working on another way to do this, but I haven't finished it yet. I have been playing with an optical mouse sensor. This way I can tell which direction the 'bot is moving and how quickly. I have the sensor talking to a Stamp and telling me which direction although not speed yet.

Just an idea.

Jonathan

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.madlabs.info (http://www.madlabs.info) - Home of the Hydrogen Fuel Cell Robot