AVR-Chat

Bernd Felsche said:
>
> I'm considering all sorts of low-power options for providing an
> analogue indication (moving needle or bar). Typical ammeters draw
> current and the quantity I want to indicate isn't directly available as
> a current... it's number-crunched. Scale will be semi-log.
>
> At first, I looked at small stepper motors but they're simply
> over-kill.  During my search, I've stumbled across radio-control
> servos... which are quite popular in robotics and the driving
> technology is certainly well known in AVR circles.

At the risk of showing my age, does no one remember moving coil meters
anymore?

See: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/galvan.html#c1

>
> The question is; has anybody used these servos for instrumentation?
>
> The accuracy doesn't need to be high; it only needs to provide an
> at-a-glance feel for the operator. The indicator only needs to be
> "accurate" at one point, which could be calibrated at "boot time". I
> expect the AVR controlling the servo to have a table of position vs
> value... with linear interpolation for points inbetween.

You should be able to create any sort of scale you want with the AVR
driving it.  They typically require very little current.


Mike