Adafruit Industries, Essential service and business: NYC – Executive Order 202.6 - Read more. Accepting essential orders - here's how.
0

Servo
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Servo

by bman22 on Tue Apr 14, 2009 7:18 pm

I have set up a way to controll my door via remote control with an older dev system i had. I decided to get an arduino and an RFID reader to controll it instead. After a bit of probing, i have determined that the servo's i have require 9VDC, as they were supplied with that system, and the system is based on 9. I am pretty sure i could power it another way, but my question is with the signal controlling it. The dev system is designed for quick and easy setup, so both the motors and the servos are controlled with the waveform. The waveform is running around 5v at peak. My question is basically, can i control these using the arduino?

Whole Waveform
Individual wave
bman22
 
Posts: 75
Joined: Mon Dec 22, 2008 2:38 am

Re: Servo

by adafruit on Tue Apr 14, 2009 9:07 pm

sure theres lots of example code for controlling servos with arduinos

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm
Location: nyc

Re: Servo

by bman22 on Tue Apr 14, 2009 10:37 pm

i don't need the code. I get the code fine. but i don't know if the header files will controll these servo's being as they are not typical servo's. does anyone have an example waveform used for controlling a servo
bman22
 
Posts: 75
Joined: Mon Dec 22, 2008 2:38 am

Re: Servo

by franklin97355 on Wed Apr 15, 2009 12:00 am

Standard servos use a pulse form 1 to 2 ms with a pause of approx. 20 ms between pulses. What do yours use?

franklin97355
 
Posts: 21491
Joined: Mon Apr 21, 2008 2:33 pm
Location: Lacomb, OR.

Re: Servo

by bman22 on Wed Apr 15, 2009 12:13 am

well, my oscilliscope is kinda old/i don't really know how to use it, so im not sure, but that sounds about right. do the pulse waves look correct. It is the second image. Seeing as it is already almost 10:30 here, i will try to figure out the duration of things tomarrow. But as i said, the proportion of wave to pause sounds about right

edit: well i realized that the signal voltage would be to low, as the one for a 5v servo is lower than one for a 9v servo. i may just buy some servo's when i get that rfid reader
bman22
 
Posts: 75
Joined: Mon Dec 22, 2008 2:38 am

Re: Servo

by bman22 on Wed Apr 15, 2009 4:50 pm

ok, well i checked it with my oscilliscope. at a 90 degree angle, the waveform has a 20ms break, and 2ms between peak and low point. I still do not know about the data line voltage, but we will see when i get the arduino.
bman22
 
Posts: 75
Joined: Mon Dec 22, 2008 2:38 am

Re: Servo

by bman22 on Wed Apr 15, 2009 8:36 pm

ok, it is working fine. I just need to get that rfid now

i realized that the motors were probably continuous rotation servo's, so i plugged one into to the arduino running the servo code. I was right. Also, i now know that they are not the "cheap" little servo's i thought they were. the hardware i was using with them just wasn't very good at adjusting them slightly. the arduino does it very well
bman22
 
Posts: 75
Joined: Mon Dec 22, 2008 2:38 am

Please be positive and constructive with your questions and comments.