Re: Choosing RC Servo Controller

On Jul 16, 8:24 am, Frank Buss <f...@xxxxxxxxxxxxx> wrote:
rgagarr...@xxxxxxxxx wrote:
The valve is moved with an RC servo
motor. The motor drive electronics includes some 0-5V digital IO
lines, but they're not suitable for creating the PPM signal required
for the servo motor.

Do you mean a PWM signal? PPM signals are used for remote controls for RC
models, but a RC servo motor usually is controlled with a PWM signal, like
described in the other posting and which you can see here:

http://www.mp.ttu.ee/risto/rc/electronics/radio/signal.htm


No, PPM is what was referenced & PPM is what is described in your link
(even says so in the text).

PWM (Pulse Width Modulation) is often used for controlling motors, &
is described below (I know it's unfashionable to refer to Wikipedia,
but it happens to have a good presentation):

http://en.wikipedia.org/wiki/Pulse-width_modulation

JM

In the light of the responses here I think the easiest thing for me to
do is to build my own controller using a 555 chip which I can control
via the IO lines. I know this should be straight forward, but I
didn't know whether there was a controller board already out there
that does what I want.

If you need two different pulse widths, which you can switch with a digital
signal, I would use a microcontroller, e.g. the PIC12F508, which you can
buy for $1.25. The program is about 100 lines of assembler, including
comments and the output pulse can be adjusted with 64 us resolution:

http://www.frank-buss.de/PICDigitalServo/index.html

--
Frank Buss, f...@xxxxxxxxxxxxxxxxx://www.frank-buss.de,http://www.it4-systems.de

.

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