Philco Shadow Graph Rebuilt With Arduino - Printable Version
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Philco Shadow Graph Rebuilt With Arduino - markmokris - 09-25-2018
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
RE: Philco Shadow Graph Rebuilt With Arduino - Radioroslyn - 09-25-2018
Clever idea.
For me it's just easier to rewind the original.
RE: Philco Shadow Graph Rebuilt With Arduino - markmokris - 09-25-2018
I was looking for something to use an Arduino for.
Mark
RE: Philco Shadow Graph Rebuilt With Arduino - morzh - 09-25-2018
What's in the blue box?
RE: Philco Shadow Graph Rebuilt With Arduino - John Bartley - 09-25-2018
(09-25-2018, 01:10 PM)morzh Wrote: 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.
RE: Philco Shadow Graph Rebuilt With Arduino - morzh - 09-25-2018
I thought it is a motor, but was wondering how fast the reaction would be: it needs to be very fast.
RE: Philco Shadow Graph Rebuilt With Arduino - Arran - 09-26-2018
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
RE: Philco Shadow Graph Rebuilt With Arduino - morzh - 09-26-2018
>>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.
RE: Philco Shadow Graph Rebuilt With Arduino - John Bartley - 09-26-2018
(09-25-2018, 03:46 PM)morzh Wrote: 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.
RE: Philco Shadow Graph Rebuilt With Arduino - morzh - 09-26-2018
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.
RE: Philco Shadow Graph Rebuilt With Arduino - markmokris - 09-26-2018
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
RE: Philco Shadow Graph Rebuilt With Arduino - morzh - 09-26-2018
Have you tried to re-magnetize the magnet?
RE: Philco Shadow Graph Rebuilt With Arduino - Arran - 09-28-2018
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