Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: tipipliou on March 08, 2010, 03:21:08 PM

Title: Command servos
Post by: tipipliou on March 08, 2010, 03:21:08 PM
hello
i'm making a robot(my first one),
it works with 2 servos,i'll use a 6v battery for them,and a Microship microcontroler 16f877
i want to know what I have to add (capacitors,resistors...) to the circuit? or can i just connect the servos directly to the microcontroler
thanks
Title: Re: Command servos
Post by: waltr on March 08, 2010, 03:26:47 PM
Beside the standard bypass cap and the MCLR pull-up on the the PIC. You'll need a LDO 5Volt regulator to power the PIC with input and output caps.

Power the servos directly from the 6V battery. The servo's control signal can be connected directly to a PIC output pin.
Title: Re: Command servos
Post by: tipipliou on March 08, 2010, 03:42:13 PM
ok,thanks a lot
another question: if i use another microcontroler(for sensors)  ,can i connect it directly to the first one or not?


PS:sorry if my english is .......
Title: Re: Command servos
Post by: waltr on March 08, 2010, 06:52:03 PM
If both processors are supplied with the same voltage, say +5V then the output pin from one can be directly connected to the input pin of the other.
If the two processors are running from different voltages, say +5V and +3.3V then it will depend on a the exact processors you are using and may or may not be able to directly connect them. In this case always read the data sheet very carefully.

Quote
PS:sorry if my english is .......

I have no problem with your English.
Title: Re: Command servos
Post by: BEAMer on March 08, 2010, 09:27:20 PM
One important thing about servos. provide a good current...

Or else the behaviour may be erratic and you may waste time suspecting the pulse width to be the problem.
A typical RC servo will consume about 500mA. Since you are using 2 servos use a battery that can provide at least 1.2A

BEAMer
Title: Re: Command servos
Post by: tipipliou on March 08, 2010, 11:16:03 PM
ok,thanks
for the current,i'm using NIMH Battery with 2500 AmH ,so i shouldn't have any problem
thank you again