Author Topic: steper motors vs motor encoders  (Read 4060 times)

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Offline paulstreatsTopic starter

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steper motors vs motor encoders
« on: January 17, 2008, 09:24:22 PM »
So,

Im thinking of entering a micromouse competition either this year or definately next year (to get a brass cheese ;D), And i would like other peoples thoughts on wether to use stepper motors where i can control the positional movement versus wether to use normal motors with encoders so i can detect the positional movement.....

I dont want to use stepper motors plus encoders because of space limitations, Since steppers are usually bigger than normal motors, but then adding an encoder makes a normal motor take up as much room as a stepper.

Offline airman00

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Re: steper motors vs motor encoders
« Reply #1 on: January 17, 2008, 09:47:11 PM »
hmmm

steppers are harder to use but once you interface them properly you can use the  rotation logging characteristic easily.

Motors with encoders are easier to use and interface.

Your choice, I personally would take steppers since I have two broken printers ......
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Offline paulstreatsTopic starter

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Re: steper motors vs motor encoders
« Reply #2 on: January 17, 2008, 09:51:32 PM »
yeah i just salvaged 2 from a printer, but then again i have loads of motors and can easily make some encoders.

Im hoping to get a full pros/cons list from this thread aswell, the contest wont be for 5 months yet....

Offline SmAsH

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Re: steper motors vs motor encoders
« Reply #3 on: January 17, 2008, 09:55:04 PM »
yea i just went down to that factory and went through about 4 priners and got about 6 steppers from each...
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Offline airman00

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Re: steper motors vs motor encoders
« Reply #4 on: January 17, 2008, 10:01:29 PM »
yea i just went down to that factory and went through about 4 priners and got about 6 steppers from each...

Now the question is , do you know how to use them......  ;)
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Offline paulstreatsTopic starter

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Re: steper motors vs motor encoders
« Reply #5 on: January 17, 2008, 10:04:22 PM »
6 stepper motors from a printer? WOW you have a good imagination....

Offline airman00

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Re: steper motors vs motor encoders
« Reply #6 on: January 17, 2008, 10:07:31 PM »
lol

i didn't catch that  i thought it read "4 printers and got about 6 steppers"

I believe Smash has been caught in a little lie .............. :o

lol, its ok we won't tell
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Offline paulstreatsTopic starter

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Re: steper motors vs motor encoders
« Reply #7 on: January 17, 2008, 10:10:33 PM »
I was actually amazed that both of the stepper motors that i got from the epson printer were the same type, I expected 2 obviously, 1 for paper loading and 1 for print head moving, but i was utterly amazed that they were both the same.

ps bet he says thats what he meant...

Offline airman00

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Re: steper motors vs motor encoders
« Reply #8 on: January 17, 2008, 10:18:46 PM »
LMAO    :D    :D   :D


but really the same type ???

I didn't open up my printers yet , but Ill look into it tomorrow  . I'm doing some heavy documenting the entire day on my line follower/ obstacle avoider  . I have like 50 pics all with explanations on the side. Once the members tutorials editing program is fixed  i''l upload everything.

Ill make a new topic announcing it.

Smash , did you honestly take apart a printer and get steppers?


P.S. lol , i also made a big rotating platform that tracks you  using an IR rangefinder , just for fun . Maybe ill post a video of it tracking me , but I can't add BB since its illegal to ship it to my city. Maybe a ping pong ball shooter...... lol
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Offline paulstreatsTopic starter

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Re: steper motors vs motor encoders
« Reply #9 on: January 17, 2008, 10:25:14 PM »
Quote
P.S. lol , i also made a big rotating platform that tracks you  using an IR rangefinder , just for fun . Maybe ill post a video of it tracking me , but I can't add BB since its illegal to ship it to my city. Maybe a ping pong ball shooter...... lol

I have entered something similar into the $200 robot contest, I just need to work on the foam disc firing platform. You could probably use my firing system for ping pong balls with a bit of modifying (if i get it finished in time. Ive done everything but the firing part)

Offline airman00

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Re: steper motors vs motor encoders
« Reply #10 on: January 17, 2008, 10:28:17 PM »
cool

PM me or email me when you posted the firing mechanism , thats really cool

are you taking an existing electric disc shooter or creating your own from scratch?
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Offline airman00

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Re: steper motors vs motor encoders
« Reply #11 on: January 17, 2008, 11:01:11 PM »
lol I dont think Smash is going to reply to this thread anytime soon, lol   :D
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Offline krich

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Re: steper motors vs motor encoders
« Reply #12 on: January 17, 2008, 11:34:13 PM »
I just realized, lately, that I enjoy  SmAsH's questions and airman00's corresponding responses more than anything else in these forums...

 :D

Offline airman00

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Re: steper motors vs motor encoders
« Reply #13 on: January 17, 2008, 11:41:49 PM »
lol


I'm here to help everyone!   :D
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Offline SmAsH

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Re: steper motors vs motor encoders
« Reply #14 on: January 18, 2008, 12:10:01 AM »
umm what.....heres a photo of the printer (the one thats not broken) little blurry from phone...
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Offline ed1380

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Re: steper motors vs motor encoders
« Reply #15 on: January 18, 2008, 12:43:22 AM »
http://www.polytypeamerica.com/products.asp?prod=39&cat=23&hierarchy=0|36

all that is necesary has been spoken ^

EDIT- let me add this pic
« Last Edit: January 18, 2008, 12:46:09 AM by ed1380 »
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Offline SmAsH

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Re: steper motors vs motor encoders
« Reply #16 on: January 18, 2008, 12:58:27 AM »
hey who said i looked like that
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Offline ed1380

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Re: steper motors vs motor encoders
« Reply #17 on: January 18, 2008, 01:04:56 AM »
how about another one
(click for full size)

« Last Edit: January 18, 2008, 01:08:15 AM by ed1380 »
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Offline airman00

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Re: steper motors vs motor encoders
« Reply #18 on: January 18, 2008, 07:35:52 AM »
umm what.....heres a photo of the printer (the one thats not broken) little blurry from phone...


Smash you are disappointing me , I'm sorry but I don't know whether I can believe you anymore
( was there ever a hexapod or a sonar bot)



http://www.polytypeamerica.com/products.asp?prod=39&cat=23&hierarchy=0|36

all that is necesary has been spoken ^

EDIT- let me add this pic



LOL , ed1380
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Offline bukowski

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Re: steper motors vs motor encoders
« Reply #19 on: January 18, 2008, 11:03:42 AM »
Quote
P.S. lol , i also made a big rotating platform that tracks you  using an IR rangefinder , just for fun . Maybe ill post a video of it tracking me , but I can't add BB since its illegal to ship it to my city. Maybe a ping pong ball shooter...... lol

Hey airman, did you use an algorithm similar to the edge finding algo?
I've been thinking about stuff for next halloween, and i am somewhat familiar with the edge finding, but the drawback is the oscillations that occur when it is looking for the edge.

Offline airman00

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Re: steper motors vs motor encoders
« Reply #20 on: January 18, 2008, 11:22:27 AM »
this is the pseudo code of my algorithm

scan left and right
read IR rangefinder
if value < threshold   ' there is an object detected
then scan left until value > threshold
then scan right until value > threshold
make a loop
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Offline bukowski

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Re: steper motors vs motor encoders
« Reply #21 on: January 18, 2008, 12:53:26 PM »
Yeah, this would still cause it to oscillate between the edges. I guess I could have two scanning servo's finding the left and right edges of the object, and have the base on a separate servo finding the differential.

Offline airman00

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Re: steper motors vs motor encoders
« Reply #22 on: January 18, 2008, 12:59:54 PM »
Actually if you have two sensors on one scanning  servo you could oscillate between it once . and until both of the sensors or one of them see the object. Then you could allow the scanner to remain stationary as long as at least one of the sensors sees the object. And then scan , etc.

Why would you care about the oscillations anyway , what kind of halloween project


P.S. It kinda looks cooler with all the scanning about constantly . But i think i will add a second IR sensor to see if the above idea would work. ( now to find a good deal on a Sharp IR sensor)
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Re: steper motors vs motor encoders
« Reply #23 on: January 25, 2008, 08:16:14 PM »
Quote
use stepper motors plus encoders
thats just silly :P

To answer your question, calculate the accuracy you need, and the accuracy you'd expect with your choice. I think accuracy will be the determining factor.

I'd go with what I can buy thats already integrated. If you can find a small motor that already has a built in encoder, that will save you days of extra work. I remember seeing one really cheap just recently but can't remember where . . . a google search should find it.

 


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