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Author Topic: Using the Earth's vector magnetic potential  (Read 102583 times)
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It's turtles all the way down
You might be able to get a pedometer at your local dollar store. These can be easily hacked to make a rudimentary counter. They have a little weighted switch the contacts of which can be brought out to count and tally external events. They usually also have a reset button. With a few protection diodes and a resistor, the switch input might even trigger from the electrostatic field of a sphere whizzing by.

I have hacked one of these in the past to perform a counting function just to see if it could be done. Only problem is it may not count to a high enough value for you.



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I don't think any of the methods of counting the sphere-sphere discharges will be reliable, because the motor might "miss" and experience double discharges (or noisy discharges).

If I were you, I'd go to a junk yard (or that musty place in your shed) and dig out an old/broken VCR.
Inside, there are reflective tape-reel sensors, that you can use to sense the rotations optically.
   
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... .-.. .. -.. . .-.
The pedometer idea is an interesting one, perhaps because i'm sure i've seen them at the dollar store and am intrigued about repurposing anything like that.
VCR's were/are treasure troves. They have good long distance matched I/R LED's in them too,


Yep, the '555-A-Like' would be an option and thanks for including it in your thoughts.
That's part of the idea of the thing, to have the core functionality of the timer expanded to do other measurements and show them on the screen.
There are 7 analog inputs, 13 digital input/outputs and even PWM on some pins of an Arduino Nano, so such an idea would be a good addition.

A Hall effect sensor can trigger a counter and be timed for how ever long you wish to sample the rotation data.
By having 2 pots on it already, the timings can be set and either auto triggered on the first pulse change, or you could manually trigger for a timed period when the DUT reaches top speed. Similar to a RPM meter but with more flexibility.
   
It would be a good time to change the firmware to a menu system, then other useful gadget items can be added.
I'll sort out the firmware and upload a demo video when it's running, if it sounds like a plan.


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Guys, such an overwhelming response !! Thank you.  O0

We're not really interested in knowing how fast the rotor is spinning, we really want to know how much quicker it is in say, CCW versus CW rotation over a given time. I just used 5 minutes as an arbitrary figure.

So, with this in mind..... I have been thinking of making a simple lever that will push a vertical rod ( fixed to the rotor ) either to the left or right and in doing so also triggers the start function.

This start function should ideally, operate not just the timer/counter but also a relay to energise the HVM too.

The outcome, hopefully, is that we should see a different count ( CCW CW ) dependant on the motors orientation thus proving/disproving Cyril's theory.

Have I made sense ?   :)   Sadly my fingers just can't keep up with the pace my mind's running at !!  :D

Cheers Graham.


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Yes, you made sense explaining your idea, but I must object to it on the basis that any mechanical interference with the disk's rotation will decrease the credibility of the result.
That's why I am a strong proponent of contactless methods for counting these rotations.

We're not really interested in knowing how fast the rotor is spinning, we really want to know how much quicker it is in say, CCW versus CW rotation over a given time. I just used 5 minutes as an arbitrary figure.
Due to the properties of calculus, any inclusion of a time period during which the angular velocity of the disk remains constant, will decrease the precision of the meaning of your result (e.g. how many times the disk turns in a 5min period).
In other words, don't include periods, during which the disk is not accelerating (...or close to it).
   

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Yes, you made sense explaining your idea, but I must object to it on the basis that any mechanical interference with the disk's rotation will decrease the credibility of the result.
That's why I am a strong proponent of contactless methods for counting these rotations.
Due to the properties of calculus, any inclusion of a time period during which the angular velocity of the disk remains constant, will decrease the precision of the meaning of your result (e.g. how many times the disk turns in a 5min period).
In other words, don't include periods, during which the disk is not accelerating (...or close to it).

Dear Verpies.

Fair comments....  O0

I guess you're suggesting I need to find another method of starting the rotor off on it's travels ? Electromagnetic pulse ?

The answer to your second point, I assume, is to find out how long it takes to reach a steady speed and then use a lower figure of time for the actual experiment ?

Kind regards, Graham.


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I guess you're suggesting I need to find another method of starting the rotor off on it's travels ? Electromagnetic pulse ?
You could, but that would be needlessly complex.

If putting the stationary ball between the rotary balls is able to initiate the rotation, then go for it - just make repeateable positioning stops.
If it is not, then one mechanical impulse to start the rotor is tolerable, especially if it is repeatable.  For example a single swing of an initiating pendulum or a ball rolling down a ramp and colliding with your disk to give it a predictable kickstart.


The answer to your second point, I assume, is to find out how long it takes to reach a steady speed and then use a lower figure of time for the actual experiment ?
Yes
   
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You can also hack an ordinary LED digital clock and make it a counter by bringing out the signal line that normally gets it's sync signal from the 50 Hz mains line, and tie an optical sensor to that line. In your case it will be reading 50 revolutions per second increment , so you will need to work the final reading to the number of elapsed seconds, minutes, hours total that will reflect number of revolutions.

You can work in total elapsed seconds x 50 = # of revolutions

With a single piece of reflective tape on the rim of the disc:

10 seconds elapsed = 500 revolutions (10 x 50)

one hour elapsed = 50 x 3600 = 180,000 revolutions.

five minutes three seconds elapsed = (300 x 50)+ (3 x50) = 15150 revolutions.

For a long run, the +/- 50 count precision may be adequate

You could also put 50 pieces of reflective tape around the outside of the disc so that 1 sec = 1 revolution

Or divide the revs with tape any way you like.

The particular clock in the schematic does not have a seconds digit, but some do

See attachment

Small battery operated analog clock movements can also be hacked into revolution counters and this may be easier since the escapement on some advances one second per pulse, you can bring out the leads from the coil in the clock and have external events as the input to the coil.


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... .-.. .. -.. . .-.
Quote
You can also hack an ordinary LED digital clock and make it a counter by bringing out the signal line that normally gets it's sync signal from the 50 Hz mains line

Now that's a bit of gold there !
Makes easy sense...I dare say Hollywood have made good use of that nugget.


Been redoing the 555-A-Like code. After getting it ready for testing, I now have the odd situation of the Adafruit SSD1306 library producing gibberish on the screen. The U8g library works fine with its test code...scratching my head on this one and it produced bouts of Tourette Syndrome for the electronics hobbyist !
I'd like to upgrade it anyway and your project Graham seems ideal.
So will likely rewrite things to use the u8g method, as even older Arduino IDE's don't work with the Adafruit ibrary.
 ???
Ran into similar troubles with the ILI9341 library.
Might ditch the OLED and use an ST7735.
Can I throw any more useless numbers at you guys ? LOL

To energise the HVM you could use a normally closed microswitch ?
That would be mounted on the arm and therefore become open, powering the HVM.
Arcade ones have 3 terminals on them (most probably do), with both N/O and N/C options.




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ʎɐqǝ from pɹɐoqʎǝʞ a ʎnq ɹǝʌǝu
   
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It's turtles all the way down
Now that's a bit of gold there !
Makes easy sense...I dare say Hollywood have made good use of that nugget.


Been redoing the 555-A-Like code. After getting it ready for testing, I now have the odd situation of the Adafruit SSD1306 library producing gibberish on the screen. The U8g library works fine with its test code...scratching my head on this one and it produced bouts of Tourette Syndrome for the electronics hobbyist !
I'd like to upgrade it anyway and your project Graham seems ideal.
So will likely rewrite things to use the u8g method, as even older Arduino IDE's don't work with the Adafruit ibrary.
 ???
Ran into similar troubles with the ILI9341 library.
Might ditch the OLED and use an ST7735.
Can I throw any more useless numbers at you guys ? LOL

To energise the HVM you could use a normally closed microswitch ?
That would be mounted on the arm and therefore become open, powering the HVM.
Arcade ones have 3 terminals on them (most probably do), with both N/O and N/C options.

Dear Mark

Many thanks for inspiring me to get back into Arduino stuff. Although still a novice C++ programmer, I was able to build up a program for the 17 bit dual slope TC500 A to D, and even write a library for it that works.
Also rewrote a library for ICM7218C display driver as the available ICM7218A library was a different animal and would not function with the C versions.

While we're throwing numbers around I recently tested some MAX6675 K 1024 deg C thermocouple devices (around $2 USD) for future use in ECAT type testing, as well as the ADS1115 16 bit 4 channel variable gain A/D converter. Also scratched the surface of Raspberry Pi, and Pi Zero.

I will be very interested in your code, when you get it finished.
---------------------------------------------------------------------------------------------------------------------------

Paper path sensing switches from old laser or dot matrix printers require very light force to activate, so could operate off a cam on Grahams device with only a tiny load of the disc.

Alternately there are a lot of optical sensor send /receive units on those old printers which could be adapted to be interrupted by a tab on the wheel.

I think I'd like to test bringing out the coil leads from one of those battery clock movements and see what the upper limit of counting frequency would be by running it off a SGen..........when I get the time. Nice thing about that approach is it gives a non-volatile reading....holds the value without power until reset!

I wonder if Graham has an upper limit of speed he has attained with the disc?

Regards


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Dear All.

My apologies, Monday's are always fraught here.....

Many thanks for the various ideas I'm pretty sure we'll think of something between us.

Dear ION.

I have just checked the rotor, it seems to level off at 55.6 RPM. ( assuming the tachometer is seeing all 16 spheres )

I'm thinking on the lines of a Ball bearing rolling down a slope and hitting the bottom of a rod fixed to the rotor for the starting impulse. This ramp would be fixed via a pivot to ensure accurate results in either direction. If thought out well enough it could also initiate the HVM and counter also.

Kind regards, Graham.


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... .-.. .. -.. . .-.
ION - 2 of the screens you kindly sent to me ended up in the following projects:
YouTube Subscribers Counter
Retro LED Games System
Here are links to those vids, which I hope don't show embedded here or they would royally mess up the thread !
Thank you again :)

youtube.com/watch?v=kNl3T7Ls8Z4
youtube.com/watch?v=gC3FJxV7Bzw

Indeed, the idea is to expand on the 555-A-Like system, to incorporate Hall sensing and other sensor based inputs/outputs. Your thermocouple code might well be included if wished and certainly seems like a useful addition.
There are loads of example type projects of sensing, but not an all in one, as far as I can tell.
I think it may be useful to have an Open Source tailored solution for projects that we all work on.
Using a menu system, various tasks could be performed by the same unit, from stopwatch timers to relay switching to Lux measurements, a myriad all in one thing. Just attach a sensor, select and use its functions from the menu.
In Graham's case, such a thing may be useful as a backup measuring tool, an option.
I'll likely post in my Bench area with updated code..all are welcome to add to it though of course as time goes on. Or completely rewrite it lol
For now though....
I like the ball bearing idea Graham. Particularly if you had it fixed at its strike point, giving a known and same starting force from the lever in both directions. You could time how long it takes to reach that max 55.6RPM and already now have partial answers to the direction speeds question.


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Dear Mark.

Many thanks for looking into a program to measure rotations against time. This stuff is way out of my comfort zone!

There's been some re kindled interest in the " Aspden effect " ..... Remember this?

https://youtu.be/m85GS5APXfk

After concluding Cyril's experiment I'm thinking of looking at this one again. But just with a flywheel directly connected to the drive motor. Your program would be ideal IMO.

Cheers Graham.


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Dear Mark.

Many thanks for looking into a program to measure rotations against time. This stuff is way out of my comfort zone!

There's been some re kindled interest in the " Aspden effect " ..... Remember this?

https://youtu.be/m85GS5APXfk

After concluding Cyril's experiment I'm thinking of looking at this one again. But just with a flywheel directly connected to the drive motor. Your program would be ideal IMO.

Cheers Graham.

Hi Graham,

I do hope you will read what David Lawrence has to say on Flywheels in the latest post.

Quote
If a wheel is spun up having no pattern in its outer rim, then the construction of the form is free of this effect.

All the atom in the wheel are already spinning at a stationary rate.

It is where we introduce new diameters of holes or diameters of rollers, and spin them oppositely.

Ron
   
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Graham said:

Quote
Dear ION.

I have just checked the rotor, it seems to level off at 55.6 RPM. ( assuming the tachometer is seeing all 16 spheres )

Dear Graham

At almost one rev per second it is ideal for one of those battery operated clock movements to tally total # of revolutions where you pulse the coil with a switch at each revolution.

Mechanically inclined as you are, you could also bring out a small wire that hooks to the escapement and cams off the wheel to tally total # of complete revolutions. It doesn't take much to trigger the escapement so a very tiny crank or cam would present nearly no load to the wheel.

Alternately a tiny magnet on the escapement and one on the wheel would also trigger.

Regards


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"Secrecy, secret societies and secret groups have always been repugnant to a free and open society"......John F Kennedy
   

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Graham said:

Dear Graham

At almost one rev per second it is ideal for one of those battery operated clock movements to tally total # of revolutions where you pulse the coil with a switch at each revolution.

Mechanically inclined as you are, you could also bring out a small wire that hooks to the escapement and cams off the wheel to tally total # of complete revolutions. It doesn't take much to trigger the escapement so a very tiny crank or cam would present nearly no load to the wheel.

Alternately a tiny magnet on the escapement and one on the wheel would also trigger.

Regards

Dear ION.

Indeed I could.... I shall have to look next time I'm in our local Pound store.

I felt Mark's project lent itself to something like this, and how about thinking on the lines of a DC Wattmeter ? In real time like a data logger ?

Dear Ron.

At the risk of upsetting Itsu...... " Double Dutch " springs to mind. I didn't really understand what he was driving at !!

Kind regards, Graham.


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Dear Ron.

At the risk of upsetting Itsu...... " Double Dutch " springs to mind. I didn't really understand what he was driving at !!

Kind regards, Graham.

Good Skype Graham... the "moggie" reminded me of Peter Sellers in the Wrong Box...

https://www.youtube.com/watch?v=j73-5LRVHWM

The flywheel is the way forward IMHO, I will send you a vid when I get mine built... don't I wish, LOL

Take care,

Ron

   
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Take an ordinary dollar store laser pointer and "hack" it so that it is supplied by a larger battery so you can turn it on and leave it on. Place this pointer below the disk, pointing upward, so it shines through the clear plastic. Put one or more pieces of black electrical tape on the disk to act as "interruptors" for the beam as the disk turns. There are no electronics in the pointer that can be affected by the electric fields. Construct a simple 555 monostable circuit triggered by a CdS photoresistor or other light sensitive device and place the sensor way up above the disk, like on the ceiling, where the laser beam will strike it. When the disk turns, the black tape bit(s) interrupts the beam once, or several, or many, times per revolution and causes the monostable to trigger. Monitor the triggering frequency using the scope or chart recorder if you have one. Speed logging sorted. Less than 5 dollars in parts, excluding the scope or chart recorder. No biasing of direction mechanically or in sensing system, no physical contact with rotating parts, no chance of blowing expensive instruments from inadvertent contact with EHV.
   
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Take an ordinary dollar store laser pointer and "hack" it so that it is supplied by a larger battery so you can turn it on and leave it on. Place this pointer below the disk, pointing upward, so it shines through the clear plastic. Put one or more pieces of black electrical tape on the disk to act as "interruptors" for the beam as the disk turns. There are no electronics in the pointer that can be affected by the electric fields. Construct a simple 555 monostable circuit triggered by a CdS photoresistor or other light sensitive device and place the sensor way up above the disk, like on the ceiling, where the laser beam will strike it. When the disk turns, the black tape bit(s) interrupts the beam once, or several, or many, times per revolution and causes the monostable to trigger. Monitor the triggering frequency using the scope or chart recorder if you have one. Speed logging sorted. Less than 5 dollars in parts, excluding the scope or chart recorder. No biasing of direction mechanically or in sensing system, no physical contact with rotating parts, no chance of blowing expensive instruments from inadvertent contact with EHV.

An LED connected to the oscilloscope, and a laser pointer should do it.

https://www.youtube.com/watch?v=RfitqGLPCUY
 
   
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Courtazar, welcome to the forum.

We must bear in mind that Graham is looking for a way to tally the total number of revolutions in a given run from startup to finish over some fixed time e.g. 5 minutes, not the tachometer speed of the disc.

You will need a pulse counter of some sort to get a tally. The simplest I could think of were the clock or pedometer counters which would be fed from the optical sensors you and TK proposed.

The PRR (pulse repetition rate) would be about one pulse per second at top speed and much less when starting up, so it is a relatively slow moving disc, less than 60 RPM.

That's about ideal for the small battery operated clock movements or the pedometer.

Regards





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"Secrecy, secret societies and secret groups have always been repugnant to a free and open society"......John F Kennedy
   
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Nobody has universal frequency counters or chart recorders any more, I guess.  My Philips PM6676 would do the trick. I left behind in Canada a really neat Nixie frequency counter that I used to record revolutions of my magnet motor testbed. And a good chart recorder is hard to beat, since you have a record of time and pulses together right there on the paper.

It would be almost trivial to use an Arduino and an LCD or other display as a pulse counter.   And then it could be repurposed for other tasks as well when this experiment is done.

http://www.youtube.com/watch?v=4num28k4EnA
   

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All right, if this continues to be a problem then I have built a digital pulse totalizer (counting down from a preset) + a millisecond clock which gets started on the first pulse and stopped when count zero is reached.
I will ship it to Grum upon request, but the cost of the intl shipping will be greater than the cost of the device.
   

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Dear Verpies.

That's wonderful, thanks.   O0

This week has been a little hectic, I hope to get into the shop over the weekend. I came to start up the Milling machine and my 20+ year old VFD expired so I've had to get a replacement fitted.

Let me know what the cost of shipping will be please.

Kind regards, Graham.


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 £42 but I am not expecting you to pay it.
   

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£42 but I am not expecting you to pay it.

That's cheaper than a new set of teeth!!

Dangit.... that's 3 gone in the space of three months..... note to self, stop eating irradiated Tuna....


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