[markmokris]

I did this project a while back.  My son was in town and insisted he film it.  -- Mark K8KZ

Video:

https://www.youtube.com/watch?v=SXlzx2DwkJw


   

   

   

   

[Radioroslyn]

Clever idea.
For me it's just easier to rewind the original.

[markmokris]

I was looking for something to use an Arduino for.

Mark

[morzh]

What's in the blue box?

[John Bartley]

What's in the blue box?

I don't know but I'd guess a signal controlled motor to adjust the vane of the indicator.

[morzh]

I thought it is a motor, but was wondering how fast the reaction would be: it needs to be very fast.

[Arran]

It's likely sluggish compared to the original movement, which was just a form of variometer like an analog Ohm or Volt meter, which just moves with changes in AGC voltage rather then having to think about things first.
Regards
Arran

[morzh]

>>which was just a form of variometer

you mean - galvanometer? It's a crude form of Weston/D'Arsonval galvanometer, indeed used in all analog meters.

[John Bartley]

I thought it is a motor, but was wondering how fast the reaction would be: it needs to be very fast.

They can be very fast. All of the gasoline powered inverter generators that I have worked on use the same sort of system for engine speed control, and that has to be at least as fast as this indicator.

[morzh]

I hope so.

Motor is not as reactive. It takes more time for the engine to rev up, then for a human hand to pass the station when rotating the dial while looking at the indicator: the angular speed could be quite high even with slow rotation, and very little needed to pass the tuning point.

[markmokris]

It's not a great solution. It is a little slow, and you can even hear the servo make a bit of motor noise as it turns. The servo, the little blue thing, takes commands from the Arduino microcontroller to turn to an angle between 0 and 360 degrees. I did it as more of a novelty than anything else.

I am usually one for authenticity, and this is reversible if I get a working shadow meter. I tried rewinding the coil twice, and I couldn't seem to get t to work very well.

Mark

[morzh]

Have you tried to re-magnetize the magnet?

[Arran]

A Galvanometer, yes, that's the word, I must have been a bit off when I typed that. But still, the shadow meter movement should react much like a magic eye tube if it's working properly, charging up the magnet is a good idea.
Regards
Arran