I've upgraded to a larger microscope body and higher magnification 40x objective lens.
Tools, Parts, and Files
- M3 screwdriver
- needlenose pliers
- 3/32” drill bit (specifies METRIC)
- Well-tuned 3D printer
- 3x 30mm M3 hex head screws
- 6x m3 washer
- 2x 8mm M3 screws (pan head)
- 6x rubber bands 1mm cross section by 15cm unstretched
- jumper wires for Raspberry pi to LED
- white LED, 3mm dia. and ~40 ohm resistor (or two 22 ohm resistors in series)
- OR 7mm 6-LED endoscope with 2 meter cable (optional, but allows another view of the sample and dimmable light)
- objective RMS mount objective, 160mm RMS tube distance, 195mm lens to focal plane distance.
Raspberry pi equipment:
- Raspberry Pi
- Raspberry Pi Camera
- Keyboard, Mouse
- HDMI TV, monitor, or converter
- microUSB power supply, 2A or above
3D print Files
Most files are in the OpenFlexure Github
- main_body_LS65.stl (this is a much larger body than standard)
- sample_clip.stl 2x
- large_gear.stl 3x
- tilted_foot.stl 3x
- illumination_and_rear_foot_sample_8mmLED_25arm.stl (file for mounting endoscope camera)
The LS-65 microscope body printed with its two rear legs detached. I repaired it with some vulcanizing rubber glue, i.e. barge cement (UHU power glue).
I then discovered my rear leg (illuminiation_and_rear_foot_sample_Z60) was not tall enough for the LS-65 body I'd printed. To remedy this, I edited the OpenSCAD file. I also changed the LED size to 8mm. At the bottom of the file are editable details for its X and Y dimensions:
original, my first and second tries at editing the file:
I used much smaller rubber bands for the feet attachment, and a smaller paperclip to pull them through. This made assembly of the knobs far, far easier than before.
Calibration, Magnification, image defects
I bought a stage micrometer-- a small ruler mounted on a slide-- in order to check the magnification. There are 100 rules in a millimeter, so each one is 0.01mm, or 10μm. The model I bought is a MEIJI Techno MA285.
Using ImageJ I set the scale of the image. I have almost 10 pixels per μm, and my image is approximately 210μm x 280μm.
The image also reveals that I got some dust on the sensor while assembling the optics. This raspberry pi sensor has been fit five or six times, and I'm not surprised. The next sensor I have will experience less change-over and hopefully not get dusty:
I'm not sure my rubber bands pull enough. I'm having trouble with the knobs skipping, and I can't use the full motion of the LS_65 body. I had hoped not to double them up, as the single bands made assembly a breeze, but will go back and try that.
The stage lighting has a serious color gradient, I'm not sure what to do about exposure and white balancing.
The feet still wobble a bit, and the microscope really seems to need a mount other than just its feet. There is also vibration when using the zoom functions. I believe mounting it to a plate and encasing the microscope will solve this issue.
I should fork the repository on Github and add my build files and bill of materials.
I'm going to calibrate the zoom with a stage micrometer and check it against 2μm Polystyrene Latex (PSL) beads.