Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Trumpkin on December 28, 2007, 06:00:24 PM

Title: wheels
Post by: Trumpkin on December 28, 2007, 06:00:24 PM
would this be hard to attach to standard size servo horns? http://www.pololu.com/products/solbot/0184/ . Also, I don't really understand the whole frequency thing wth servos I thought that that was only for radio but apparentley it isn't. Would this distance sensor http://www.pololu.com/products/misc/0136/ work for adaptive mapping?
Title: Re: wheels
Post by: Trumpkin on December 28, 2007, 06:18:14 PM
If I understand it right after you modify your servos you have to program the right frequency to have it zeroed out, is that right? since I used my RC radio to modify mine how do I figure out the frequency? For all I know I'm probably asking a questions that don't exist. ;)
Title: Re: wheels
Post by: ed1380 on December 28, 2007, 06:35:15 PM
plug into the treceiver and it should center automatically, if it's not getting a signal to turn
Title: Re: wheels
Post by: Trumpkin on December 28, 2007, 06:44:13 PM
I did modify my servos with my reciever I just wnat to know how to program it now
Title: Re: wheels
Post by: ed1380 on December 28, 2007, 06:52:27 PM
you cant program servo's unless they're digital.

and if it's a RC robot it doesnt need programming. it needs a transmitter
Title: Re: wheels
Post by: Trumpkin on December 28, 2007, 07:12:12 PM
it's not an rc robot i just modified my servos with my RC reciever/transmitter. I can't figure out how to program my servos with my $50 robot microcontroller (which I'm almost done with).
Title: Re: wheels
Post by: ed1380 on December 28, 2007, 07:16:32 PM
you cant program servo's unless they're digital.

and if it's a RC robot it doesnt need programming. it needs a transmitter

helping you program the mcu is out of my field, since i was never able to get mine working. (admin programmed it for me  :-X )
Title: Re: wheels
Post by: Admin on December 28, 2007, 10:34:45 PM
In the modify servo tutorial there is a .hex file. Upload that to your microcontroller, and it will automatically send out a centering PWM. Hook your servo up to a port, and your servo will automatically center.

As for mounting wheels:
http://www.societyofrobots.com/mechanics_chassisconstruction.shtml#wheels
Title: Re: wheels
Post by: robonoob on December 29, 2007, 06:20:58 AM
umm why do u need to center ur servos?? i mean if they are modified then it don't matter if it is centered or not or does it? well at least the robot i will make with the arduino development platform i will just tell servo to go 180 or 0 and then it turns...(i don't know if u understand me or not :D) btw u center the potentiometer in the modifying process don't u?
Title: Re: wheels
Post by: ed1380 on December 29, 2007, 10:05:05 AM
read the tutorial :p

yes you center the pot when moding it, or replace teh pot with 2. ~2.2k resistors

how it works
when the signal tells it to move center it'll actually stop, and 0, 180 as you said make it move right, left

if you didnt center it. telling it zero will still make it move
Title: Re: wheels
Post by: robonoob on December 29, 2007, 11:01:51 AM
if you didnt center it. telling it zero will still make it move
by that u mean if u tell the servo to go to 90?
anyway... i dont know if any other microcontrollers accept this or not but with arduino u just tell the microcontroller to detach the servo if u want it to stop :)(or at least i think it is like this :D i mean i cant find another good reason why to attach and detach the servos)
Title: Re: wheels
Post by: Trumpkin on December 29, 2007, 12:05:49 PM
Maybe I'm just confused about nothing  ::) I'm not talking about modifyng the servo, I'm talking about actually programmming the robot. I thought there was something about programing the right frequency for the servos.   ???
Title: Re: wheels
Post by: robonoob on December 29, 2007, 12:33:08 PM
Maybe I'm just confused about nothing  ::) I'm not talking about modifyng the servo, I'm talking about actually programmming the robot. I thought there was something about programing the right frequency for the servos.   ???
well as i've understood the thing the frequencies matter if u are using an unmodified servo... am i right?
Title: Re: wheels
Post by: ed1380 on December 29, 2007, 10:08:57 PM
if you didnt center it. telling it zero will still make it move
by that u mean if u tell the servo to go to 90?
anyway... i dont know if any other microcontrollers accept this or not but with arduino u just tell the microcontroller to detach the servo if u want it to stop :)(or at least i think it is like this :D i mean i cant find another good reason why to attach and detach the servos)
yeah i meant 90


admin wrote many codes for teh $50 robot. one was the photovore code, and the other was to center your servo's before modding them and gluing the pot. but since you used an RC system to do that, you dont need to download and program that code

and frequency matters for all servos