Hi,
Just finished building motorised microscope with low-cost optics. I used 0.8:1 ratio gears for speed. Also since I didn’t have sangaboard and illumination pcb, I used alternatives, and used white teflon tape instead of pmma lens (I recall that i read it somewhere, but i’m sure i’m not right because live picture seems too grainy). What can i do to correct shaky movement of stage (i added a video link, and sometimes it doesn’t move at all). I also added a captured image, microscope seems not focus on left upper side and i see a red spot when looking at stream at empty stage.
For slide scan, i recently watched tech demo on youtube and there is slide scan option with live stiching preview. I also recall seeing it Rwanda post. Is there a way to obtain slidescan option?
Thanks in advance!
Stage movement: Watch WhatsApp Video 2024-07-24 saat 22.19.09_b1220a07 | Streamable
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Well done on your build @zealkarel.
There are several points in your post, I shall try to address some of them.
A scatterer, like white PTFE tape, instead of the condenser lens at the position of the lens should give a large illuminated area with a reasonably large numerical aperture. The downside would be that much less light would make it into the camera lens. A grainy image might be that the gain has to be very high on the camera. With the low cost optics the illumination NA required is quite small, so a condenser lens with longer focal length should be OK, if that is easier for you to find.
The motion you show is diagonal, but seems to travel in a bit of a staircase trajectory. What happens if you move in only x or only y? Is that smooth or jerky? What are the occasions where it sometimes does not move at all? Overall the motion should be fairly smooth but not perfect. Your symptoms may be that one of the actuators is partly broken.
A coloured spot when you have no slide in place is the white balance and flat field correction not quite working properly. In the settings tab you can re-do that calibration. I would first disable the flat field correction to see the uncorrected illuminaton, you may then need to run the auto gain and shutter speed. Then check that the illumination is reasonably good over the entire area, with no really dark patches. It does not need to be fully uniform, but there does need to be at least some light in all areas. Then run the calibration again.
Poor focus in one corner could be from several different sources. The stage might be not quite flat - if you pack up one side of the slide with paper can you make it better? The lens may not be quite straight in the lens spacer part. The camera may be at a small angle relative to the camera board.
The stitching is discussed in another thread.
Good luck with further testing on your microscope.
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Hi again, thanks for reply @WilliamW,
I bought some lenses from aliexpress with specifications diameter 13, focal length 8. But it was no edge lens, so it didn’t fit. I purchased different lenses again, but didn’t receive them yet. I’ll try to update when shipment arrives. Can i try to fix lens with some colorless tape?
I tried to move only x or y this moment, x axis movement seems normal, but y axis sometimes doesn’t move or too shaky. Don’t know what to do, i had so many failures to this point. This is 4th printed main body.
Video: Watch ScreenRecorderProject1 | Streamable (sorry for watermark).
Coloured spot and focus doesn’t seem to fixed with re-calibration and packed up paper, respectively.
Again thanks in advance.
Starting with the colour. If what you are talking about is the slight ‘blotchy’ pattern in your lower image, then I think that is from low overall light level. The flat field overall looks to be well corrected, and the patch size is uniform across the image and about the size of the correction cells in the algorithm. It is also pinker in some cells but greener in other cells, which looks like noise. Low light means that noise in the calibration images makes a difference to the calibration, and the next image has different noise.
For the condenser lens, you could glue or tape a lens in the condenser body. It is not a precise illuminator.
Finally jerky motion on y not x unfortunately does suggest damage. What were the symptoms of you previous main body failures? Have you got any pictures? It can really help the project if we can understand failure modes. If we know what is happening we can think how to change the design or instructions.
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It’s worth mentioning that sticky stage movement can result from missing out the washers in the actuator assembly, or from not having lubricated the long M3 screw that goes into the brass nut. It’s often tempting to skip those steps, but they make a big difference.
Various people have also reported issues with the motors - if you think one motor is better than the other, it’s easy to check by swapping them.
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Hi again, thanks for replying @WilliamW and @r.w.bowman,
For colour as i mentioned i was using white teflon tape it seems it doesn’t allow enought light for illumination. I’ll try with again condenser lens and post pictures again. I also plan to build with a 40x objective (actually two low-cost, and two with a 40x objective). Will condenser lens with focal length 8 result in good image with 40x objective?
For main body failures, first one stage same symptoms, stage sometimes didn’t move and at some point, i heard a snapping noise and assumed body failed but later realized that didn’t cut ties for rear legs and i think that was the snapping noise. Since i was new to 3d printing (my first print was just_leg for printer test), assumed print failed, and printed new one, same problem stage was not moving as expected, printed new one, same problem. I have bodies 2nd and 3rd print also this one. Will try to dissamble actuators and post pictures.
As for the @r.w.bowman mentioned;
Checked for washers they seem in place. Also lubricated M3 screws but maybe didn’t use enough oil. But since i couldn’t find brass nuts for actuator assembly was using DIN932 A2 grade m3 nuts. Can this be the problem?
I have motors to spare and will try them too and post results again.
Again thanks for replying.
Hi again,
Sorry for replying too late.
Shaky movement was due to ripped viton bands (i think). I disassembled actuators and noticed blotches on the top walls. Also later i figured out my band assembly tool was not symmetric (right side didn’t fit well to holder, printed again now fits well). Actuators seems fine. Now trying to assemble microscope again will post again later how it works. I added photos for top wall and actuators.
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