Automated Stack & Stitch System Videos

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

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mjkzz
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Post by mjkzz »

kaleun96 wrote: My hope was to tap directly into what powers the flash recycle indicator LED but as you see in the photos linked above it's a minuscule SMD component that would be a nightmare to wire onto. With time, patience, and a oscilloscope I'm sure I could find a better place to tap into it but in the mean time I'm going with an externally mounted log-scale light detector to pick up the LED brightness. A bit tricky in of itself and less robust but it should work I think.
I am not sure you need to tap into the circuit because you have the LED, just use a photo-sensor, an OP-AMP and then fine tune the gain to get a logic high (or low) when the LED is fully lit. Just glue the photo-sensor onto the LED with blackened material (black hot glue)

I do not recommend differential circuit though, because the LED might light up slowly for some brands, thus making it difficult to detect the first order derivative for all types of flashes.

But as far as I remember, the LED is not very accurate, sometimes, output energy can vary by half stop, even with some high end flashes, like Nikon SB900, etc. My Canon 580EX, that particular unit, has about 1/3 stop variation.

Just my 2 cents

mawyatt
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Post by mawyatt »

I have a few Arduinos that someone sent me awhile back, but haven't attempted anything with them yet.

I decided at the beginning of the Automated S&S development to go with the Raspberry Pi 3B, didn't think the Arduino could handle the overall effort and wanted to use the usual computer Keyboard, Mouse and Display rather than pushbuttons and tiny displays. With VNC this works out well, as you have these but don't require them connected to the Pi.

If I could get the Trinamic working with an Arduino acceptably then I could interface the Arduino with the Pi. I only want to use the Trinamic on the optical axis motor, so only need one per S&S System Setup.

But for now, I'm just going to pass on the Trinamic as I've spent way too much time on them already.

Agree, looks like the TT350 would be a challenge to tap into the LED. Noticed the energy storage capacitor is 750uF at apparently 330V, this equates to a potential energy of ~41J (or WS). Thought they were higher than this?

Just thought of another option since you are using an Arduino which has analog inputs I recall. Place a voltage divider across the energy storage cap, say something like 132 to 1, then bring out the reduced voltage to the Arduino analog input to A/D convert. I would use something like a 3.9Meg and 30K resistors, this will give ~2.5 volts with the capacitor voltage of 330 volts and only dissipate 30mw. Bring the reduced voltage out to a 3.5mm connector on a pigtail, then you can use a standard 3.5mm audio cable to your Arduino. Be sure and place the voltage division resistors inside the case and only bring out the reduced (~2.5 volts) voltage for safety reasons. Run a routine that digitizes this voltage and set a "trip" point acceptable for continuing to the next step. This should produce a highly repeatable "trip" point although the resolution isn't very good because of the voltage attenuation.

!!!!!! CAUTION !!!!!! If you not familiar with high voltage circuits please not not attempt this, find someone who is and let them do this for you. The energy storage capacitor has ~330 volts stored and can be lethal, this must be carefully discharged before attempting any modifications.

Best,
Last edited by mawyatt on Sun Apr 07, 2019 10:10 am, edited 1 time in total.
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

kaleun96
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Post by kaleun96 »

mjkzz wrote: I am not sure you need to tap into the circuit because you have the LED, just use a photo-sensor, an OP-AMP and then fine tune the gain to get a logic high (or low) when the LED is fully lit. Just glue the photo-sensor onto the LED with blackened material (black hot glue)
Yeah so I'm currently mounting an external light-sensor to the outside but your comment makes me wonder whether I could have mounted it internally. Perhaps but I did try and take apart the flash and I couldn't get it apart without risking breaking it. But that would remove the problem which I will need to deal with: external light interference. I think I will make a shroud around the detector to reduce that and even without the shroud the Arduino is capable of differentiating between the LED being off and it being on.
I decided at the beginning of the Automated S&S development to go with the Raspberry Pi 3B, didn't think the Arduino could handle the overall effort
Makes sense, Arduinos become tricky when trying to balance speed and memory.
If I could get the Trinamic working with an Arduino acceptably then I could interface the Arduino with the Pi.
You could try port the C++ code to python as well but could be difficult unless you were comfortable writing to registers etc in python to begin with. As you say though, you've spent enough time on those drivers for now. Best to finish what you have and see how it works for you over a longer period before investing time on the Trinamics.
This should produce a highly repeatable "trip" point.
Interesting idea, and more accurate then the LED. My worry would be getting access to the components, it's a tricky flash to disassemble in my experience.

mawyatt, out of interest, where do your interests lie with macro subjects? I think I've only seen you test on the CPU so far but ultimately will you be using this rig for subjects with more complex shapes?

mawyatt
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Post by mawyatt »

You could try port the C++ code to python as well but could be difficult unless you were comfortable writing to registers etc in python to begin with. As you say though, you've spent enough time on those drivers for now. Best to finish what you have and see how it works for you over a longer period before investing time on the Trinamics.
Agree, I'll probably look in this later when I have more time, but for now the Tic-500s are working superbly.
Interesting idea, and more accurate then the LED. My worry would be getting access to the components, it's a tricky flash to disassemble in my experience.
Just be careful around the energy storage cap, it can "bite" you!!

If you want better resolution you could add a zener diode in series with the top resistor in the voltage divider. For example a 300v zener like the LiteOn Z300B (or three 100v 1N4764 in series) with a 47K and 3.9K resistors will give you ~0.4 volt resolution. These are not expensive diodes, less than $1.
mawyatt, out of interest, where do your interests lie with macro subjects? I think I've only seen you test on the CPU so far but ultimately will you be using this rig for subjects with more complex shapes?
At the moment my interests lie mostly in semiconductor chips, one's that I've designed or participated in, or others involving new technology. Later I'll probably get involved with insects and such as most folks do here.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

mjkzz
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Post by mjkzz »

kaleun96 wrote:
mjkzz wrote: I am not sure you need to tap into the circuit because you have the LED, just use a photo-sensor, an OP-AMP and then fine tune the gain to get a logic high (or low) when the LED is fully lit. Just glue the photo-sensor onto the LED with blackened material (black hot glue)
Yeah so I'm currently mounting an external light-sensor to the outside but your comment makes me wonder whether I could have mounted it internally. Perhaps but I did try and take apart the flash and I couldn't get it apart without risking breaking it. But that would remove the problem which I will need to deal with: external light interference. I think I will make a shroud around the detector to reduce that and even without the shroud the Arduino is capable of differentiating between the LED being off and it being on.
ah ok, I was thinking in the line of generalized hardware solution, sort of making a sensor module for Arduino, 3 wires, VCC,GND, and signal,

But anyways, good luck with your project.

kaleun96
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Post by kaleun96 »

mjkzz wrote:ah ok, I was thinking in the line of generalized hardware solution, sort of making a sensor module for Arduino, 3 wires, VCC,GND, and signal.
That's exactly it, one of those Adafruit log-scale light sensors.

mjkzz
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Post by mjkzz »

kaleun96 wrote:
mjkzz wrote:ah ok, I was thinking in the line of generalized hardware solution, sort of making a sensor module for Arduino, 3 wires, VCC,GND, and signal.
That's exactly it, one of those Adafruit log-scale light sensors.
That is interesting. But what I have in mind is a bit different -- to build a light sensor with logic level output and it would not require analog read, can be logically AND'ed so you can put multiple together till all of flashes being monitored has their charge light lit up and feed that signal to Arduino

Anyways, do not want to hi-jack this thread, so when I have time, I might post a design.

mawyatt
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Post by mawyatt »

I found some internal photos of the Godox TT350 and it's beyond my ability to tap into the signals on this board:
https://fccid.io/2ABYNTT350/Internal-Ph ... os-3263879
My hope was to tap directly into what powers the flash recycle indicator LED but as you see in the photos linked above it's a minuscule SMD component that would be a nightmare to wire onto. With time, patience, and a oscilloscope I'm sure I could find a better place to tap into it but in the mean time I'm going with an externally mounted log-scale light detector to pick up the LED brightness. A bit tricky in of itself and less robust but it should work I think.
As you know I use studio strobes since I don't have to deal with batteries and the recycle time is pretty quick (~1 second) at lower power.

A fast recycle time strobe is the Adorama Rapid 600 (same as Godox), it's a 600WS studio strobe with a recycle time of 0.9 to 0.05 seconds from full power to 1/128 power. So at power levels you are likely to use for macro stacking it will be less than 0.1 second! It's also a very fast optical output, at 10% pulse width is varies from 5ms to 50us from full to 1/128, so likely 100~200us for macro work.

This strobe recycle time is so quick you could shoot 10 frames per second or faster!!

Something that I had overlooked is the strobe "beep", when occurs when the strobe has recycled and is ready for another flash. If you listen in the videos you can hear the beep. You could also detect the "beep" with a simple circuit.

My preference is to just have the strobes setup so the recycle time is faster than the time between steps and not have to worry about sensing the recycle indicator and deal with the extra complexity & wiring. With the Rapid 600 mentioned this becomes a non-issue at any stacking speed I can envision, so may be worth considering.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

mawyatt
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Post by mawyatt »

I've added another vibration demonstration video, this time with a Mitutoyo 20X and silicon chip as subject.

Like before this is the vertical S&S System sitting on a kitchen table and extremely sensitive to any source of induced vibration. The Nikon D850 is zoomed out a maximum of 16X, thus the "effective" magnification is 320 :shock:


https://drive.google.com/file/d/1Pcp7HS ... sp=sharing

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

Smokedaddy
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Post by Smokedaddy »

Looks excellent to me, especially considering it's on a table top and the mass isn't that great to begin with compared to others I've seen. Nice job! Can't wait to see a pano-chip.

mawyatt
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Post by mawyatt »

Thanks JW.

The kitchen table is small, light and very vibration prone, so thought this would be a good base to do the test. Kind of like a worst case scenario.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

lothman
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Post by lothman »

mawyatt wrote:I've added another vibration demonstration video, this time with a Mitutoyo 20X and silicon chip as subject.
EXCELLENT result, this shows also the benfit of the THK ball screw - no Backslash. Otherwise you would get the same spot in focus at 16x

mawyatt
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Post by mawyatt »

lothman wrote:
mawyatt wrote:I've added another vibration demonstration video, this time with a Mitutoyo 20X and silicon chip as subject.
EXCELLENT result, this shows also the benfit of the THK ball screw - no Backslash. Otherwise you would get the same spot in focus at 16x
Agree, THK rails are very good without any apparent backlash or wobble. Using a long ARCA plate and clamp to attach the THK works very well also.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

mawyatt
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Post by mawyatt »

Here's a video of a small flower floating in water in a bottle cap. This was to show the effects of the vibration reduction concepts. As you can expect the flower is floating so in will respond to any movements from anywhere including air currents. Extremely sensitive subject to movement and will show any induced vibration effects from the motor/rail/camera/lens movements.

The setup is the same D850 at 16X with a Mitutoyo 20X objective, for an effective magnification of 320X with a subject floating in water :shock:

This is on the same Wemacro base but now is sitting on a couple boxes on the floor next to my desk, I got kicked off the kitchen table :roll:

Note the long time constant to vibration of the setup and the lack of inducing such by the motor/rail/camera/lens movement, even when moving 25000 microns at 6500 microns/second!

Also, note that the subject is constantly moving at a slow rate due to thermal or relaxation effects, this is not due to lens/camera/rail/motor induced movements.

Here's the video link.

https://drive.google.com/file/d/1muI-oX ... sp=sharing

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

Lou Jost
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Post by Lou Jost »

Hi Mike, thanks for making this test! The video is too big (300+ Mb) for me to view right now with my bad internet connection, maybe late tonight when the traffic goes down. But from your description it sounds like everything is working even better than you had expected!

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