How to define scan area?

I would like to scan several slides like shown in the picture. I need to scan the whole circle. The circle is in the middle of the slide and measures 1cm in diameter. Any suggestions?

The normal scan mode scans a square area. It should be easy enough to set that up to cover at least your circle. To scan just the circle, or to make the scan size or position more automatic will require something custom. I think this is one for your own code using the Python library. There looks to be a reasonable boundary to your sample, so it should be possible to determine when the current position comes to the edge of the sample.

Thanks for the reply William. I dont mind being a square area. I am cannot get the stage to travel 1cm. At some point the gear keeps turning but the stage does not move any further. I think that in theory If I perfectly center the stage it should able to move 5mm each way, right? I do it by aligning the holes under the stepper motor. I set coordinates to 0. Then I move X: -44000 ; Y:-44000 because that is when the gears stop responding but still does not reach the end of the circle

Ah, I see. I have not explored the total range of motion. I would probably take the motors off and move it by hand to get a better feel for what is happening. Overall the range is set by the maximum flex angle and the leg length. The deltastage page says the microscope travel should be 12mm. I was looking there because I think Delta has longer legs and a wider travel, but it does not say.

As the microscope is parametric in OpenSCAD it should be possible to make a stage with longer legs for more movement (at larger step size). This is currently difficult in practice, but @j.stirling is leading a code clean up that should make it simpler to make custom builds using microscope components in OpenSCAD and generate STLs.

It is possible to make one with longer legs or to change the lever reduction on the XY stage.

Just out of curiosity about how far can you move. And does it look even on both sides of the travel? If one of the viton bands break then the motion of the stage towards the motors stops working properly.

I am thinking how to accurately measure the travel distance. I will find a calibrated slide and record that. I am thinking that perhaps the X and Y screws may not be long enough. is that possible?

That also is possible. We use 25mm hex bolts. Where is the length of the thread.

A calibrated slide is one way of measuring. Another is to move the microscope fully one direction,Put something heavy in contact with it (something that wont move) then move the microscope fully the other way and measure with a ruler. It wont be super accurate, but will let us know it if it is closer to 9mm or say 5 mm.

I could not find 25mm hex bolts in amazon US. I am using 20mm M3 bolts with the nut holding it in place from the opposite side making it even shorter. I need to find a better bolt :slight_smile:

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McMasterCarr are the best place in the US to get hardware.

Hi William. I keep thinking about what you said on delving into the python library. It may be possible pre-determine the motion of the motors to cover the circular area of the slide. Can you show me where these files are ?

I should admit that I am talking about things that I know exist, but that I have never used myself.
The python library is linked from

Thanks. I think this is too big of a task for a mere mortal like me. :slight_smile:

As is, the scan area is roughly 7mm at best. I am 3mm shy each way :-1:. This means I can scan 3/4 or the entire circle area. So I Just finished modifying the STL file to make the legs 1cm longer :+1:. Will print tonight. Also, receiving new M3 screws this weekend :clap:. Wish me luck :crossed_fingers:

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Hello there,
Would love to get some feedback on your improved version with longer legs. What is the new scan area and do you maybe even have the changed stl files to look into them? Did you experience any difficulties after changing the microscope? We got a similar problem and your experience would be very helpfull.
Best wishes

Hi Julia. I added 1cm to the legs which approximately increased the scan area by 2-3 mm. I could not add more without having to do a major modification of the design. This includes modifying the camera adapter to be higher as well. Overall, my stage can scan a 10x10mm area approximately. I feel it can be more but the stepper motor screws and nuts act funny if I try to go beyond that. Scan area is the biggest limitation of this wonderful machine. I decided to adapt my projects to minimize this problem.

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Sorry for the the drift in topic but it’s in reference to the image above.

I’m curious about the orientation of the condenser lens in the above image. I’ve been struggling with getting even illumination and wondering if I have my condenser in the wrong way. It’s opposite to the image above however the instructions suggested flat side down? Does it make a difference?


No. You are right. The less goes the other way. It fell off when I wanted to take the pic and put it the wrong way. I noticed that there is a sweet spot you need to find to get even light. Need to play some with the condenser position and the auto calibrate to get it right.

Ok thanks for the reply. I tried it in the orientation of the photo and it didn’t seem make any difference so I think I have a lot of fiddling to do with the illumination.