Photomultiplier Tubes camera build

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Re: Photomultiplier Tubes camera build

Postby Steve Anderson » Sun Jan 01, 2017 3:51 pm

Harry, suggested positive feedback for the LM311 attached. This should give you about 0,5V of hysteresis which means the signal from the phototransistor needs to be greater than this. But if it isn't just increase the value of the 150k feedback resistor until things work.

It may also be advisable to put a 100n disc-ceramic cap right across the power pins on the underside of the board as close to the LM311's power pins as possible.

Added components are in blue...

Steve A.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Jan 01, 2017 9:51 pm

HI Steve
I will give that a go i know this help does not just appear and you have to work this out so thanks heaps also to Gary on the last circuit change ,i would of made the changes today if i saw to post !
I could not see any change to the pulse on Garys 100k from pins 2 to 7 but i really looked more into the trouble making side of the circuit today .
What i did today was pretty much rebuild the motor control tried to copy this circuit for the motor side of the control .

Below is my two sided bistable PLL testing control ///i only have one ic in its socket at a time to test what works better at the moment neither is giving me much love !

The 555 pulse seems enough to control the motor but until i can switch the thing on again and it sits on 400 hz and not over shoot and such its not much good to me and may as well go manual which with my tweaking i am pretty much doing now.

With the circuit below the first 100k is bypassed for the 555 but its need for the PLL because pin 13 to the gate of the mosfet it drops away all i see is noise .....
I can pull the ic out and i can see its doing nothing ,more me and how good the trimmers can be adjusted thats doing the controlling . :roll:

I don't know why the PLL is not working on 5 volts or 12 but 11.55 there abouts !...i have got pin 9 to ground i just tried that as i saw one version of this circuit used that idea .

If it takes me all year i will try and make this thing run at 400hz ...may be on page 364 with luck :lol:

i can see as gary and klaas has helped me advice with the front end opto reflector and LM311 and sync this is also important to control that motor but i can see as far as the PLL gos something is not right here ..i will go looking for another brand of this PLL my luck i have 20 of this one !

Below are newyears555.wav this is out of the lm311 and 2555 is out of pin 3 555 to the mosfet gate on 555 bistable motor control....
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby gary » Sun Jan 01, 2017 10:42 pm

Harry, this circuit change won't help with the wiggly sync bar - but it should make the motor run to speed more reliably - all other things working of course.
gary
 

Re: Photomultiplier Tubes camera build

Postby gary » Sun Jan 01, 2017 10:46 pm

Harry, on your new cct, why is encoder pulses connected to pin 4 of the 555?

(I have only had a quick look - will check agin tomorrow).
gary
 

Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Jan 01, 2017 11:04 pm

gary wrote:Harry, this circuit change won't help with the wiggly sync bar - but it should make the motor run to speed more reliably - all other things working of course.


Yes Gary i understand its more motor control the change to the LM311 i will see how Steves change gos next time i can get to my soldering iron ...the better lining up of the lines instead of a wavy look might not be needed if i can once again get the motor control to work as i can just use the crystal for the sync worked before just have to repeat it :roll:
The 2 control circuits PLL and Bistable i really have not had much trouble in the past which ever i used .this time its kicked my bottom a few times if that can be fixed either one of the them ,that will make every thing else work ,
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Jan 01, 2017 11:13 pm

gary wrote:Harry, on your new cct, why is encoder pulses connected to pin 4 of the 555?

(I have only had a quick look - will check agin tomorrow).


I have always used this as a guide to a 555 bistable Gary ..i have no idea i just read copy test if its works i go with it .

Do you think i have the the pulses from the clock and the encoder wrong way around ?
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Tue Jan 03, 2017 11:19 pm

Steve Anderson wrote:Harry, suggested positive feedback for the LM311 attached. This should give you about 0,5V of hysteresis which means the signal from the phototransistor needs to be greater than this. But if it isn't just increase the value of the 150k feedback resistor until things work.

It may also be advisable to put a 100n disc-ceramic cap right across the power pins on the underside of the board as close to the LM311's power pins as possible.

Added components are in blue...

Steve A.


Hi Steve i added the parts to the circuit only difference i put in a 1meg trimmer in place of the 150k resistor for now till i know whats correct .i really need to get this on the dual trace scope again .
The decoupling cap is added as well ,pulse looks cleaner .
The 1meg trimmer the pulse looks about the same on the higher range i have to see against the opto sine wave and adjusting the circuit again to Gary's procedure .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Jan 08, 2017 3:08 pm

I am still working on the motor control below is processed and unprocessed sync pulse on garys TBP version 2 ...
Stuck with the same Pll have not been able to find any thing other than the version i have got all 20 of them ...any case still trying to work out if this thing is controlling the disk and its not just the supply settings to the motor .
Either way i can get pretty close .
I was also looking into the opto switch and taking readings as i rotated the disks encoder to each white section and i was not getting the same reading such as 4 volts nexts one 3.89 so on ...
i know Gary mentioned it has to be glued pretty flat to the disk even so a slight movement say disk wobble will cause these voltages to change with the different distance to the photo transistor ..this is a back and forward problem with the voltage but i think it also means the photo transistor is seeing a different pulse widths along the horizontal a sight as it is ....causing the ragged sync line .
if i had used a vcr head i don't think this would of been a problem but the cd mount of the cd is obviously no where as good .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Jan 08, 2017 9:53 pm

I had another look at my 555 bistable replacement circuit for the PLL and i noticed a circuit mistake with pin 6 ..after disconnecting that it now works as it has in the past not bad at all ,sync recorded shows it can hold its own against a pll doing the same job and in my case a lot better ! slight roll i should be able to adjust out .
Ruff change to the circuit below ...have not put in the sync select switch ...mainly dealing with the motor control .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Wed Jan 11, 2017 7:29 pm

gary wrote:Harry, this circuit change won't help with the wiggly sync bar - but it should make the motor run to speed more reliably - all other things working of course.


I have been thinking about the the encoder sync with the varying pulse width due to mechanical problems ...
So having the mechanical sync varying a touch each pulse line or the crystal clock which is fine spot on as long as the motor speed is correct ...i have been wondering about a 3rd option hook the sync mono up to what is controlling my motor the combination of both from the bistable switching ,i will see what effect i get .....what i hope and i get might be different but i think its worth a shot to test ...it will be interesting
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Thu Jan 12, 2017 12:46 pm

I tried the bistable as a 3rd sync source option but it pretty much still gives a ragged line plus it effects the motor speed which might be just an adjustment to compensate....even so it seems without changing the mechanical problem to stop any slight wobble the crystal sync is the neatest option for what i have got .

Least i am now understand whats happening here ..

What i still a little puzzled over is using the crystal sync why are video lines across the horizontal still a touch distorted ...i think i will now look into seeing if i can adjust the PMt voltage a touch better via either the bench or inverter could just be an electronic distortion .

Did some quick tests today hooking up the pmt again checking how the bistable motor control works its pretty stable enough any way enough to do crystal sync tests again any bump to the camera will cause a slight sync movement ..any way i am a lot happier with this now not bad for the old 555 timer /

BTW the wavs might need to be inverted in TBP i swapped computers on record forgot to check what this one does
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Thu Jan 12, 2017 5:52 pm

A touch off topic but i was looking at a motor i had which has something on the end i would say was perhaps an encoder with some electronics.. of some sort or a Ac generator any case makes a easy replacement for an encoder disk.
I will keep this in mind for the future ,i also have 2 other types similar to this motor which give the same results ..i can get this one up to around 1.5khz .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Fri Jan 13, 2017 6:56 pm

More testing today with a quick televising of a little visitor who was wondering what i was up to her white top is the distortion when she moves ..still a bit sensitive some thing to reflective like white .
The Toy test came out well ..
I also had a 4th go at a second lens and it now works i had the others i think out of scan position ...i need to paint some gaps in the case as some lights getting in causing static ..i think if thats fixed it would at least match this one ..good to know i could use a scrapped lens for a future camera ..
i will get around to trying a simple lens out of interest ...these ones have zoom but any movement bump to the nipkow the speed gos off so a big bounce effect on the video .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby Harry Dalek » Sun Jan 15, 2017 11:46 am

I have been testing the PMT with the inverter i now know the operating range is about between 500 and 600 i can see it starts to work in the 490s and to much gain mid 600s.

all the tests below were done with the inverter via a battery ....dual 12 volt supply still from the bench power supply .

I have been using an pretty poor battery as i made this thing to work at 1200 volts not needed here at all .

The tests today were just a cloudy morning via room light .

The croc video was done on the low end of the voltage range 510 volts ...what its like increasing the light on a lower voltage i would like to see if the camera would be able to work out side one day .

I am pretty happy the inverter as far as noise none at all but looks like i will have to adjust the inverter to run at a lower voltage range to wide for the needed narrow lower voltage range at the moment ..

Yes still very messy !~ :roll

BTW i for got to adjust the crystal so there is drift again till i remember to adjust it ~!
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Photomultiplier Tubes camera build

Postby viya0414 » Thu Aug 24, 2017 3:03 pm

The yellow output of white LEDs is generated from the UV excitation of a phosphor which can be quite slow in response time. Though the PMT shouldn't much respond to it, why throw another potential variable into the equation? White LEDs are marginal even for NBTV, they may get better with time but generally white LEDs are used in flashlights and other simple devices where human eyesight is involved - and that's not particularly fast.

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