Hi Jean,

>>Servos typically have three lines, Control, Gnd, & Vcc (in that order).  The
>>Servo Control can be hooked up directly to a PIC.  The signal itself repeats
>>every 20 msec and consists of a Vcc Pulse 1 to 2 msec in length.
>>
>>The PIC can't supply enough current to power the Servo.
>
>But the PIC can supply enought power to send pulses to the pulse pin?
>And then I can connect the power and ground pin to a battery or something?

Yes.

>>I use the TMR0 Interrupt; every 18 msec, I put out a 1 msec pulse and then
>>set a counter that makes the pulse low when the value equals the counter.
>>The Counter goes on until another 1 msec is used up.
>
>So you can configure the timer that every 18 msec, it sends a pulse of x
>duration to the servo?

Yes.  Where 1.0 msec <= x <= 2.0 msec.
>
>>I bought Tower Hobbies "TS-51" Servos for $11.95 (USD).  They have others
>>that have more capabilities (and higher cost).  Note that Futaba Servos
>>require a different timing spec.
>
>Can the TS-51 be easly converted so it can fully rotate? (365 degrees)

Depends on your definition of "easy".  "Popular Electronics" had an article
on using servos with a BS1 in the Sept. 1996 issue.  The modification
consists of breaking the link between the gear position and the feedback
pot.  This was a tab on a plastic shaft that was pretty easy to do on the
the Servo shown ("HiTec"), but I seem to remember a caveat stating that
different servos are different...

Note that this mod is just for allowing the servo to run endlessly (ie as a
propulsion motor).  If you want 360+ degrees in a regular servo (with
control), you'll have to design some custom linkages/gearing.

myke
>
>Thank you very much! & Talk to you soon!
>Jean-Francois
>-----------
>Jean-Francois & Alain Joly
>jolyal@capitalnet.com
>
>

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