RC servo

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opcoded

Joined Aug 22, 2009
1
sorry for disturb... im a newbie in microcontroller... learning in process... im using compiler mikroC... wanna control 19 servo motors... can anyone suggest a suitable PIC microchip to use in controlling these 19 servo motor??? i had a PIC 16F877A... but only got 2 pin for PWM... so i had to use timer0 to control...

can anyone recommend a suitable PIC to control 16 servo motors??? wat programming method suitable? i had no experience... thanks for help...
 

mik3

Joined Feb 4, 2008
4,846
Do you have more information about the servos?

I don't think you need PWM to control them.
 

jpanhalt

Joined Jan 18, 2008
7,691
Addressing only that part of your question about which PIC to chose, you need to decide whether you want one pin per servo, i.e., you will need at least 19 output pins plus any number of additional input pins. There are methods that use multiple pins to do that. I believe this is a commercial version of a method published by Warren Schroeder that uses 33 pins to control 33 servos:
http://www.circuit-ed.com/30-Servo-HardwareSoftware-KIT-by-JVM-BOTS-P117C10.aspx

Once you get past a few servos, however, most of the projects I have seen reduce the number of PIC or other mcu pins needed and use a chip(s) like a 74HC238 or 4017 to decode/demultiplex a control signal from the PIC.

Here is a link to a project by Jeff Heiss (jheissjr) that controls 20 servos using an Atmega 16: http://www.avrfreaks.net/index.php?module=Freaks Files&func=viewFile&id=3238&sh

Following that approach, you should be able to use any one of several of the 16F or 18F chips.

John
 

steinar96

Joined Apr 18, 2009
239
You are better off using a cheaper PIC and instead multiplexing the PWM channels to multiple servos. 33 PWM channels propably means surface mount microcontrollers. You'll go trough alot less hassle with a cheap PDIP PIC with 1-2 PWM pins and as mentioned earlier in the thread a multiplexer.
 

jpanhalt

Joined Jan 18, 2008
7,691
You are better off using a cheaper PIC and instead multiplexing the PWM channels to multiple servos. 33 PWM channels propably means surface mount microcontrollers. You'll go trough alot less hassle with a cheap PDIP PIC with 1-2 PWM pins and as mentioned earlier in the thread a multiplexer.
Actually, the link I provided for controlling 33 servos uses a TH (DIP) microcontroller.

John
 
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