This is a follow up to a Zoom call with Richard Bowman regarding adaptation of the OpenFlexure microscope for use in schools. The build instructions call for use of the Sangaboard, which (a) does not appear to be readily available and (b) requires soldering surface mount components to the bare board, assuming that it is possible to obtain the bare board. We think this will present a significant barrier that will discourage use in most schools.
We’re hoping to have at least a partial build in time for discussion at the National Technology Leadership Summit (NTLS) in Washington D.C. on September 14th. The Sangaboard appears to be a potential bottleneck. Are there any suggestions for a workaround that will enable us to proceed?
The presidents of twelve education associations will be at NTLS, so this offers an opportunity to introduce them to the OpenFlexure microscope. This would be a more productive conversation if we have a working prototytpe, or at least a partial build. Any suggestions for how we might expedite this?
Welcome to the forum @maketolearn. The Sangaboard can be replaced with an Arduino nano and the motor drivers that usually come with the little stepper motors. This is detailed as the
electronics workaround. The functionality is identical to the integrated Sangaboard v0.3, the wiring is just a bit more messy. The nano converter plate in that link will only work for a Raspberry Pi 4, not a Pi 3.
@filip.ayazi has developed a prototype Sangaboard v0.5. There is a separate thread here about that with some details of how to get one, although it may not ship to your area. Sangaboard v0.5 now available - OpenFlexure Forum.
The electronics workaround references “the driver board for the 28BYJ-48 5V micro-geared stepper motor”, stating that “the board should have come with the motor.”
We use this stepper motor but in our orders from Amazon, it does not come with an included driver board. We have been using the ULN2003AN motor controller board, ordered separately. Is this the functional equivalent of the driver board that comes with stepper motor in some instances?
Yes, they are usually ULN2003 drivers.
Per preceding posts above, the goal of the OpenFlexure Microscope School Initiative is to adapt the OpenFlexure Microscope for use in schools. The following team has been assembled to work on this project. (If there are others who should be included in this effort, please note in a follow-up post.)
Make to Learn Laboratory, University of Virginia
- Glen Bull, Director & Professor of Education
- Jo Watts, Lab Manager
Biomedical Engineering, University of Virginia
A. Assembly and Fabrication Team
- Angela Taetsch
- Mikayla Jackson
B. Electronics and Software Team
- Ashley Onumonu
- Ramya Tangirala
C. Optics Team
Science Pedagogy Team
Andrea Borowczak Andrea.Borowczak@ucf.edu
Director of Teacher Education, University of Central Florida
President, Association for Science Techer Education
Katherine Cruz-Deiter firstname.lastname@example.org
- Biomedical Engineering Advisor: Shannon Barker (University of Virginia)
- Optics Advisor: Michael Littman (Princeton University)
- Software Advisor: John Maloney (MicroBlocks)
9/26/23 Meeting Notes
A problem that came up today is in Step 4 of the Actuator Assembly. The Viton band is supposed to hook to the inserter tool to connect the Viton band into the axis, but the issue is the insertion tool is not strong enough so it snapped in the middle of insertion and it needs a bigger dent so it can hold the Viton band easily. We have decided that it will be better to reprint an edited inserter tool, so we will redesign it in AutoFusion and print it to be used.
- Software & Electronics Team:
- Micro SD card
- Ethernet cord (with USB-C or USB-A adapter)
- Raspbian-OpenFlexure Software (available on the website)
- Power supply cord (sold separately from raspberry pi)
- When plugged into the laptop, raspberry pi is not showing up.
- Has power and ethernet
- The SD card is connected
@ashley_openflexure I am sorry to hear that you are having trouble with the assembly. The band insertion tool is well tested but maybe the instructions for using it are not clear. There are a couple of very important things:
- Use the band insertion tool cap over teh band insertion tool. It is mentioned in step 5 Assembly Instructions (openflexure.org) but is not shown in the image on that step. It is in the parts image before step 1 (top middle of the parts image). The cap helps to keep the pressure even on both sides and the insertion tool will not break.
2: Use the nut insertion tool to lock the actuator while you are inserting the band. This is shown in step 5. The tool will try to fall out or tilt up, you need a finger on it to hold it straight.
- It can be possible to get the band uneven when first inserted through the foot in teh first frame of step 5. Put the band in the foot and put in the insertion tool, then check that there is the same amount of the band on both sides and that the band is not trapped.
I am working on a re-design of the feet to make 3. easier. The repository for the modification is here Modify feet to locate with four prongs instead of two tabs (!339) and the file for the modified feet is feet (MR339).stl (537.6 KB). I am also trying different tools for locking the actuator more easily for 2.
installing the operating system on the instructions that you have linked to tells you how to use the
raspberry Pi imager software. When you run the imager software you will need to select
custom in the operating system selector and point it to the Raspbian Openflexure file that you have downloaded from the Openflexure web site. Setting up the SD card is the first step before doing anything else, it is a little strange that they have put that half way down the instructions.
Hi there. I apologize I come to the conversation so late. Hope your presentation went well. I have been using the openflexure microscope for medical education for quite a while. I found that I don’t need to motorized version to do this. The manual version works very well for students, is much cheaper, and provides the same learning experience. I will be glad to share my experience with you.
10/3/2023 Assembly Notes
Zach Palazzotto - Optics Team
Assembling the high resolution optics module:
The optics module, which is printed in black, failed inspection based on the plastic supports obstructing the barrel of the piece. There were 4 hair-like pieces of plastic that did not dissolve in the bath. Since these pieces were so fine, it required a nail file, tweezers, and a small scissor to remove them. I then used compressed air to clear the barrel of debris before inserting the lens.
Removing the Pi camera lens posed challenges. This lens was completely scratched and destroyed by the Pi Camera Lens tool. The tool does not snap onto the lens, instead it requires a perfect angle and grip. Trying to find this angle & grip caused a lot of scratching on the delicate surface of the lens. This does not matter for the sake of this project, but if you were lookin to repurpose/ reuse the lens, it would not be salvageable.
When attaching the objective, it was a very tight fit. In order to screw the objective all the way into the optics module, it required great amounts of strength. I had to grip the objective with a rubber tool to screw it in all the way.
The step of assembly entitled, “Assemble the high resolution optics module,” is now complete.
Could it be possible your printer needs some tuning? You should be printing everything without supports. Sometimes the inside of the tube needs some sanding, particularly if there is stringing due to calibration issues.
You shouldn’t have to fight to screw the objective. This makes me think there is a problem with the print.
10/9/2023 Assembly Notes
Zach Palazzotto - Optics Team
Assembling the Illumination:
I only had the pieces to assemble the condenser arm. Therefore, I did not mount the dovetail yet. As far as assembly goes, inserting the condenser lens into the condenser arm was the only difficult part. The lens is supposed to snap in with help from the lens tool, however it required a large amount of force by hand. The illumination cable and total illumination LED board assembled perfectly.
As the body of the microscope is almost complete, I will go into the lab on Wednesday or Friday to mount the optics and mount the illumination.
Thanks so much for this helpful feedback. We selected the first design that appeared and did not realize that a non-motorized design exists. Since we have the components for the motorized version, it would make sense to complete it if we are able. However, we hope to place one microscope with a biology teacher in Orlando, FL and another one with the head of a biology department in Texas in order to get two different perspectives on the value and use. Therefore, if the manual version works as well and is less expensive and easier to assemble, it would make sense to use the manual version for the second teacher.
If we might ask, if the manual version is just as effective for teacher, why does a motorized version exist? Is there a research application that does not come up in teaching?
We checked the first page of the instructions and found these choices:
- Motorized High Resolution Model
- Motorized Low Resolution Model
- Upright Model
Is the upright model the non-motorized version? The accompanying text said that this version is less well tested than the other versions. However, if you are having a positive experience possibly that information is out of date?
We’re using a Stratasys F170 printer that is in good calibration and using ABS print filament with a soluble support material. However, if the instructions said not to print the materials with supports, we did not see that instruction. Therefore, we printed without disabling supports (the default setting). We can try printing without supports if that’s the recommended method. It might be useful to highlight this recommendation in the instructions for those assembling a microscope for the first time (like us).
We encountered a difficulty when attaching the feet to the main body of the microscope using the o-rings. One foot went on with minimal difficulty, but for the other two, the specified o-rings seems to be too thick to fit over the hooks that hold them in place. We’ve tried using the 3D printed tool as well as a pair of tweezers, but the o-ring will simply not fit through the gap. Any recommendations to resolve this issue?
@maketolearn thank you for sharing your experiences with us.
Supports should not be used in any of the parts of the microscope. This is given on the
test your printer page of the instructions, but other builders have missed it too. We are currently revising the instructions to put that on the
printing parts page as well. Some of your issues might well be supports that have not fully cleared from the internal parts of the mechanism. We also print mainly in PLA, although I have also tested PETG.
The O-rings are a tight fit in the feet with the tool, but they do still go in reliably. To make this easier I modified the design of the feet to make more space for the tool. This is in post 8 on this thread. Did you try those new feet?
It might be helpful to post some pictures of where you are having problems. There is a lot more in a picture than one can write in a post.
These versions are the main tested configurations for the microscope. Any of them can be used without motors attached, as a manual microscope. Just omit the steps to attach and wire up the motors and Sangaboard. Then turn the large gears by hand instead.
The most common uses in research are for tiled images or long term time lapse studies, which require motorised translation or autofocus, so that is the default in the instructions.
There is a prototype version of the body for a minimal manual version of the microscope, that has not got the motor mounting lugs or the cable conduits, which makes it slightly easier to use by hand. That body will work with any versions of the Pi Camera optics and a Raspberry Pi in the normal stand for the microscope. The thread shows the very simplest version with webcam optics. That does work, but we are not able to integrate a webcam with our software to give colour correction, so the images are not as nice.
Thanks for the feedback. I’ll try re-printing without supports and see if that makes a difference. I believe we also have a spool or two of PLA. I’ll try that as well since it has been proven to work.
We weren’t aware of the new feet, so I’ll print a set of those and report back.
Got it. This makes perfect sense. I’ll take a look at the prototype. That version may be more practical for teachers who don’t need the time lapse and have more limited time for manufacturing and assembling the microscope. Thanks.