Philco Shadow Graph Rebuilt With Arduino
Posts: 109
Threads: 18
Joined: Mar 2015
City: Ann Arbor, Michigan
(This post was last modified: 09-25-2018, 08:48 AM by markmokris.)
Posts: 7,248
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
Clever idea.
For me it's just easier to rewind the original.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 109
Threads: 18
Joined: Mar 2015
City: Ann Arbor, Michigan
09-25-2018, 12:31 PM
I was looking for something to use an Arduino for.
Mark
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
What's in the blue box?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 358
Threads: 4
Joined: Aug 2015
City: Monteith, Ontario CA
(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.
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
I thought it is a motor, but was wondering how fast the reaction would be: it needs to be very fast.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 4,639
Threads: 51
Joined: Sep 2008
City: Sandwick, BC, CA
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
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
>>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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 358
Threads: 4
Joined: Aug 2015
City: Monteith, Ontario CA
(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.
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
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.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 109
Threads: 18
Joined: Mar 2015
City: Ann Arbor, Michigan
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
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
Have you tried to re-magnetize the magnet?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 4,639
Threads: 51
Joined: Sep 2008
City: Sandwick, BC, CA
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
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
Cannot Adjust an IF Transformer’s cores
|
Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM |
Cannot Adjust an IF Transformer’s cores
|
The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM |
PT-6 antenna connections
|
Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM |
Cannot Adjust an IF Transformer’s cores
|
Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM |
PT-6 antenna connections
|
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4.
Yes, pin 6 of the 7C6 is...RodB — 07:34 PM |
bridkarl
|
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM |
Cannot Adjust an IF Transformer’s cores
|
Joseph, now you are an engineer!!RodB — 06:37 PM |
PT-6 antenna connections
|
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM |
Cannot Adjust an IF Transformer’s cores
|
It works! I received the PCBs this morning in the mail, and put everything together. I reused the base from the original...jrblasde — 04:32 PM |
PT-6 antenna connections
|
I seem to have lost my way on this PT-6.
I see the antenna aerial transformer schematic - I’m reading pins 1 through ...bridkarl — 12:30 PM |
Who's Online
|
There are currently no members online. |
|
![>](https://philcoradio.com/phorum/images/bootbb/asb/right_arrow.png)
|