Magnetcially securing a smartphone to an eyepiece adapter

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Hobbyst46
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Magnetcially securing a smartphone to an eyepiece adapter

#1 Post by Hobbyst46 » Tue Dec 12, 2017 9:51 pm

The original commercial smartphone-eyepiece adapter (a $45 gadget from ebay) was practically unusable, because the phone fixtures needed frequent re-tightening and the optical alignment of the phone camera lens with the eyepiece was difficult and frustrating. Moreover, the camera lens on the adapter plate was located about 10 mm below the focal point of the eyepiece.

So I removed the original rubber holders from the adapter plate. Instead, I placed an inverted plastic box on the plate and affixed it with three wooden cubes and super-glue. The plastic box is an old microscope slide storage box (from Clay Adams) - 97mm x 83mm x 15mm. Thin plastic, flat bottom. It is used without the cover. Before the box was glued to the plate, a "coin" powerful Neodymium magnet, grade N52, diameter 18mm, thickness 2mm, was glued inside the box, on the bottom of the box. Another identical magnet was placed on the glued one (to form a pile of two magnets). More magnets could be added - three were found to hold the 5" phone (including case) securely in this arrangement.
Warning - handle these magnets with care, they forcefully collide with each other when set loose, can break or even hurt a finger - never let children nearby!
After assembly, the underside of the original box became the top plate of the adapter.

On the back side of the smartphone, on its case actually, I fixed a sticky thin (0.5mm or so) metallic disk, that is part of a vacuum gadget that secures the mobile phone to the car's dashboard (magnet on phone side, vacuum for the dashboard). This is OK since I never drive and take photomicrographs at the same time...

To use the upgraded device, I fit the eyepiece inside the adapter, then place the adapter on top and fit into the binocular head of the microscope. The slope angle of the binocular is 45 degrees. I place the phone on the plate, and it is securely held by the magnet. I can gently slide it to and fro to align the camera lens with the eyepiece. Once aligned, it is stable, does not slide or move, and photography can be performed with the lightest, most gentle touch of the screen.

I use Open Camera app (Google Play Store). Set to Macro. Focusing is a pleasure and the screen image is sharp and clear. Focusing is only controlled with the microscope knobs, not the phone itself. Thus, this adapter became a usable device, at least until I can afford better equipment.

The photos below, of unknown (to me) animalcules among alga threads in water, were taken with a 25x/0.45 phase contrast objective, brightfield (one, two) or phase (three). Cropped and resized to fit in the post.
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Afocal setup side.jpg
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Afocal setup front.jpg
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Last edited by Hobbyst46 on Tue Dec 12, 2017 11:15 pm, edited 2 times in total.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Hobbyst46
Posts: 2394
Joined: Mon Aug 21, 2017 9:02 pm

Added later for clarification

#2 Post by Hobbyst46 » Tue Dec 12, 2017 10:46 pm

The back of the phone (in case) is shown below, with the attached sticky thin metallic circle (probably steel sheet, not a magnet itself).

Also shown, in inverted position, the upgraded smartphone-eyepiece adapter. The eyepiece is secured inside its tube (the tube is an integral part of the original adapter) by means of the three concentric blue rubber adapters. The two side arms (right and left) are the fixture points for the original phone holders, which I removed. The pile of magnets inside the box are somewhat visible near the bottom and in the close-up photo.

There are three magnets here - the photo title is erroneous.
Attachments
The upgraded adapter, bottom side up.jpg
The upgraded adapter, bottom side up.jpg (22.86 KiB) Viewed 18168 times
A pile of two Neodymium magnets inside the inverted box.jpg
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Magnetic disk on the back side of phone case.jpg
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Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

JimT
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#3 Post by JimT » Thu Dec 14, 2017 11:28 pm

Hobbyst46, Rotifers.

Quite an interesting setup. Much better than just holding the phone over the eyepiece. Looking forward to more images.

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#4 Post by Hobbyst46 » Fri Dec 15, 2017 11:15 am

JimT - Thanks.
Now I have learned something about the biology of the rotifers. Recorded a clip of them eating (or at least trying to suck food) but the AVI or MPEG are rejected by the site software - it notified that they cannot be uploaded. Clip was too big ?? Less than 1Mb...
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

MichaelG.
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Location: NorthWest England

Re: Magnetcially securing a smartphone to an eyepiece adapter

#5 Post by MichaelG. » Fri Dec 15, 2017 9:23 pm

I use Open Camera app (Google Play Store). Set to Macro.
I downloaded 'Open Camera' ... Thanks: It looks very promising.
Unfortunately, I must be having a bad day ... I haven't yet found the 'Macro' setting.

Could you point me in the right direction, please ?

MichaelG.
.
edit: Sense of direction recovered !
https://opencamera.sourceforge.io has a link to:
https://www.iconfinder.com/icons/81105/ ... n#size=128
Too many 'projects'

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#6 Post by Hobbyst46 » Sat Dec 16, 2017 12:35 am

MichaelG.

The main screen of the OpenCamera app shows two different setup icons. One is the cogwheel and the other is the three dots in a column. The latter one opens the options. First row - top row that is - flash options.
Second row is focusing options. From left to right: Autofocus, infinity focus, macro (flower icon) lock focus and continuous focus (do'nt know what that means...). Below that row you find photo modes liie resolution etc.
The cogwheel setup offers many more options but not the focusing options.

Good luck - please update if found!
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

MichaelG.
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#7 Post by MichaelG. » Sat Dec 16, 2017 9:51 am

Hobbyst46 wrote:Good luck - please update if found!
.
Menu items found, thank you
The explanatory details are on the first of the two links that I added last night.

For the benefit of others: The available options vary according to the particular 'phone hardware.

It looks a superb App ... Thanks again for the reference.

MichaelG.
Too many 'projects'

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#8 Post by Hobbyst46 » Sat Dec 16, 2017 10:17 am

MichaelG - thanks for the link.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#9 Post by Hobbyst46 » Sun Dec 24, 2017 10:19 pm

Some more data acquired with my smartphone-over-eyepiece setup: (1) Rotifer (2) Diatom Tetraselmis (from a culture) in water, moving at natural speed, and (3) Tetraselmis in a dilute gelatin solution (actually a sol, not solution) in water. The size of Tetraselmis is ~6-7 micrometers. In my original video clip, the four cilia that give the creature its name are better visible - I don't know exactly why.
16X or 25X/0.45 objective, brightfield, 16MP camera and zoom.

https://youtu.be/r5YVkytqtJY
https://youtu.be/HfGojJeZvAA
https://youtu.be/0su558DWcrU

To be improved next year!
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

ajmckay
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#10 Post by ajmckay » Fri Dec 29, 2017 3:09 am

Hobbyst - those videos are great!

I'm not really familiar with the device you're using - but I like the idea of a magnetic mount a lot because like you, I have a binocular scope so I might be installing and removing it frequently.

I'm thinking of using the 3D printer to make one of these: https://www.thingiverse.com/thing:1768834 , and based on this post finding out a way to incorporate a magnet as well, if anything so I can leave the positioning clamps alone and use the magnet to make sure it doesn't fall out of the mount.

Thanks for the post!

MichaelG.
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#11 Post by MichaelG. » Fri Dec 29, 2017 8:37 am

ajmckay wrote:Hobbyst - those videos are great! [ ... ] Thanks for the post!
+1
What particularly impresses me is the evenness of the illumination.
... I was expecting to see some fall-off at the corners, but these prove me wrong.

MichaelG.
Too many 'projects'

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#12 Post by Hobbyst46 » Fri Dec 29, 2017 10:50 pm

amjmckay and MichaelG - Thanks for the compliments.

The key feature, I think, was placing the phone such that the camera lens is at the focus - that is about 20mm higher than the top lens of the eyepiece itself (it is a highpoint eyepiece).

amjmckay: the adapter I used (and modified) is "Microscope eyepiece installation adapter for smart phone SMHMCR63" from Japan, I purchased it through Amazon, not Ebay. It was much less expensive than other types (ca. $40).
Please note, that the magnets I use are Neodymium magnets, I have just verified that it was grade N45 (pretty powerful, but there are higher grades) and I had to use three of them in series. With larger smartphones (mine is a Samsung S5) maybe a higher grade is better (there are grades N48 and even N52). These magnets are great playthings for grown-ups, but be careful! Anyway, I will gladly provide more details if needed.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

ajmckay
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#13 Post by ajmckay » Sun Dec 31, 2017 4:19 am

Hmm. I'm not sure I quite understand what you mean by placing the camera at the focus, 20mm higher than the top lens.... Got a pic?

MichaelG.
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#14 Post by MichaelG. » Sun Dec 31, 2017 7:51 am

ajmckay wrote:Hmm. I'm not sure I quite understand what you mean by placing the camera at the focus, 20mm higher than the top lens.... Got a pic?
I think that might be just a slip in terminology ... for 'at the focus' read 'at the eyepoint'.
... The important thing is, of course, that the results are astonishingly good.

MichaelG.
Too many 'projects'

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#15 Post by Hobbyst46 » Sun Dec 31, 2017 12:05 pm

Well, "focus" is not entirely wrong term here. I actually meant the focus of illumination rays, not the focus of the image forming rays.

To citefrom the web site microscopy.berkeley.edu/courses/TLM/eyepieces/eyepieces.html:

"The eyepiece focuses the real image (from the objective) outside of the eye lens at a position called the eyepoint or exit pupil, which corresponds to the position of the focal point of the eye. Eye relief is a parameter of eyepiece design and determines the distance between the exit pupil and the eye. It must be greater than 5–7 mm to avoid observer difficulties and is usually 7–13 mm. High eyepoint oculars, designed for glasses wearers, have an eye relief of 15–20 mm." So much for the focus...

An even clearer picture is displayed in the site MicroscopyU. They show the illumination ray path in red, on the left side of their page, and the image rays in yellow on the right side. We see that for the illumination, the crossover point of the rays coming out from the eyepiece is at the "eyepoint" (that is indeed the best term here, thanks MichaelG!). And the eye relief, or distance between the top lens of the eyepiece and my eye (i.e. my own eye lens) or my camera's lens is indeed about 20mm for my WHK eyepieces. These are termed "high eyepoint".

I will make a schematic drawing of my setup and post it ASAP.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Hobbyst46
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#16 Post by Hobbyst46 » Sun Oct 14, 2018 12:29 pm

To clarify the mechanics a bit.

When the microscope lamp is on and all setup for convenient viewing (brightfield, open iris aperture), placing a frosted glass or oiled paper or any translucent plastic above the eyepiece will reveal the eyepoint - marked as asterisk in the drawing below, where the light beam is narrowest.

Scheme A shows the purchased adapter (in blue) installed on top of the eyepiece. It consists of a sleeve wrapped around the eyepiece, an inclined plate and small rubber stoppers (deep blue).
B - stoppers removed, and a box with magnets added to fill in the distance to the eyepoint.
C - phone is placed on the plate and the camera can be aligned with the eyepiece by gentle sliding of the phone. Once it is aligned, it will keep its position.
Attachments
Afocal smartphone with eyepiece adapter.jpg
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92111
Posts: 158
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Re: Magnetcially securing a smartphone to an eyepiece adapter

#17 Post by 92111 » Sun Oct 14, 2018 1:25 pm

hello
A good adapter design:
Make full use of gravity, support, and bevel to keep your phone still, rather than using a fixture. Because this allows the phone to be quickly put on and off, the design of this foreigner is the best I have ever seen.
https://www.youtube.com/watch?v=KzsLNMJxOGU
This is my modified adapter. Although it still need improve , But i have already purchased A Trinocular head.i want to design a smartphone adapter to the Trinocular head ,just like the picture.
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