Re: Driving servos from a PC

On 2006-12-14, Pete Verdon <news@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
As part of a construction project for a charitable event, I need to
build a number of big analogue dials (like an old-fashioned voltmeter)
controlled by a series of PCs (each computer drives two dials). Accuracy
isn't critical, but I do have a fairly strict budget restriction.

One possibility seems to be to use an RC servo to move a big cardboard
needle. I've not used servos before, but a little research suggests that
the required position is commanded by altering the pulse width of a ~5v
50Hz square-wave signal a little either side of 2ms.

As I said, I don't have much of a budget. I also have limited
electronics knowledge. But is it totally unrealistic to consider
controlling these servos via a soundcard output?

not entirely, but unless you need PC control it'd be easier to just
use a 555 and a pot for each.

variable duty-cycle cicuit:

----+--- vcc
|
.----------------------|--------+
| | |
| +--------+ |
V | | |
.--[POT]-->|--. | . . . .|. . . . |
| | | . VCC(8) . |
| | | . . |
`---------|<--+ +--RES(4) OUT(3)--+--> out
| . 555 .
+-------TH(6) DIS(7)----
| . .
+-------TR(2) CV(5)--
C1 | . .
===== . GND(1) .
| . . . .|. . . .
| |
+-------------+
|
---+-- gnd


--

Bye.
Jasen

.

Relevant Pages

  • Re: Driving servos from a PC
    ... controlled by a series of PCs (each computer drives two dials). ... but I do have a fairly strict budget restriction. ... controlling these servos via a soundcard output? ...
    (sci.electronics.misc)
  • Driving servos from a PC
    ... As part of a construction project for a charitable event, I need to build a number of big analogue dials controlled by a series of PCs. ... but I do have a fairly strict budget restriction. ... I've not used servos before, but a little research suggests that the required position is commanded by altering the pulse width of a ~5v 50Hz square-wave signal a little either side of 2ms. ... But is it totally unrealistic to consider controlling these servos via a soundcard output? ...
    (sci.electronics.misc)
  • Re: Driving servos from a PC
    ... controlled by a series of PCs (each computer drives two dials). ... controlling these servos via a soundcard output? ... Cannot for the life of me remember where I bought it in the UK, ... both are ideal for controlling multiple servos ...
    (sci.electronics.misc)
  • Re: internet remote control
    ... internet. ... NE2000 driver is a standard LIB available from the website. ... You can use the apache web server as a base for controlling ... serial port to control servos and some simple parallel port ...
    (comp.robotics.misc)
  • Re: Multiple R/C servo control
    ... > I've been doing lots of tests with controlling R/C servos lately, ... > 1-Assume there is an array of servos controlled by the uP ... > 2-Drive all servo lines high, set TMR0 with the time interval ...
    (comp.robotics.misc)