Building a Raspberry Pi-Powered Microscope Using LEGO

Big Data Digest

Source: IEEE Spectrum

Translation: Da Meng, Niu Wanyang

LEGO is truly a source of joy for adults, allowing them to use their imagination to build their favorite houses and structures, and it also aids in the creation of precision instruments, making it a favorite among countless geeks!

Previously, we reported that someone used LEGO to build a part sorting machine, so there’s no need to worry about classifying LEGO parts anymore. This time, we discovered a LEGO enthusiast, Yuksel Temiz, a researcher at IBM Zurich, who built a high-precision electric microscope using LEGO, Arduino (an open-source electronics prototyping platform), and Raspberry Pi (a credit card-sized microcomputer) to photograph microfluidic chips from various angles!

This is truly a case where work and hobby go hand in hand, and it’s impressive. Netizens commented: “Even after watching, I wouldn’t know how to do it, and if I tried, it would be a waste.”

Yuksel’s decision to DIY the microscope wasn’t a spur-of-the-moment idea.

On one hand, IBM Zurich has a tradition of discovering microscopes. In 1981, Gerd Binnig and Heinrich Rohrer invented the scanning tunneling microscope here.

As a DIY enthusiast, Yuksel naturally did not want to fall behind, so he followed the tradition of his research institute and aimed to create a modular electric microscope worth $300.

Furthermore, Yuksel indeed needed a custom microscope for his research, as taking pictures of microfluidic chips is extremely difficult!

Because chips are generally quite large, standard microscopes cannot capture the whole image; however, Yuksel’s research team needs a standard microscope to resolve fine features that ordinary cameras cannot.

Yuksel also studied papers from other research groups, and it was clear that everyone faced this challenge: the need for a more refined instrument that can capture chips from multiple angles.

With this goal in mind, Yuksel took some free time to redesign a multifunctional laboratory instrument that could photograph macro images from almost any angle.

The design of the imaging microscope utilized a large amount of technology and materials, including LEGO for the main structural components and 3D printed gears and frames to drive its moving parts. The stepper motors, which allow for precise movement, are driven by a motor driver board and controlled by an Arduino board. The Raspberry Pi Zero and Pi camera module are used for capturing images.

The initial design included custom control boards and parts printed on a high-resolution printer, but before public release, the microscope was redesigned to be assembled using off-the-shelf boards and parts that could be printed on lower-cost low-resolution printers.

Yuksel’s first prototype was a Raspberry Pi camera module mounted on a platform, which could move in three-dimensional space using a linear stepper motor from an old CD drive. The Raspberry Pi camera was an ideal choice because it allows manual adjustment of key parameters like ISO settings and exposure time.

IEEE Spectrum wrote about Yuksel’s repeated adjustments during the production process.

Yuksel first carefully removed the plastic shell that fixed the lens, revealing the CMOS image sensor, and designed a clever mechanism to move the lens back and forth, allowing for high-magnification macro photography. This device worked well for a time, but it was very fragile. Yuksel accidentally broke the lens mechanism several times, and due to carelessness, the moving parts exceeded their limits, damaging the image sensor.

So he decided to take another approach: completely remove the lens from the Pi camera; then, take the objective lens from a low-cost USB microscope and mount it on another CD linear drive, allowing the objective lens to move back and forth along the optical axis of the Pi camera; and then use LEGO to create a shell to protect the exposed sensor of the camera.

However, the result of this attempt was that, aside from being deterred by the high price of the linear module used in the microscope, there were no results. The travel distance of the CD drive was too short, still unable to achieve a wide magnification range.

Subsequently, Yuksel switched to using the lead screw mechanism used in 3D printers. He did not use the commonly used 8mm diameter threaded rods and bearings, but instead used 3mm diameter parts to ensure the device’s compactness. Additionally, moving the objective lens could cause stray light issues, so he decided to move the camera sensor instead.

He built a platform that allowed the subject to move and rotate along the x-axis and y-axis. Ultimately, six micro stepper motors with gearboxes were used to achieve platform movement, tilt the microscope, adjust its distance to the object, and focus the image.

Illustration: James Provost

The angle is perfect!

Because chips are usually made from highly reflective or transparent materials, providing uniform lighting to the chips is also crucial.

The LEGO microscope can place samples under uniformly illuminated conditions provided by an LED backlight module. The sample can move back and forth, sideways, and can rotate to find the desired angle. The microscope body can tilt up and down and adjust its distance and focal length from the sample to provide different levels of magnification [bottom]. By moving the lensless camera module within the LEGO shell, the focal length can be adjusted by changing the distance between it and the bottom of the shell.

Yuksel mentioned that he often designs his own Arduino control boards for compact devices. This time, he designed a control board measuring 18×18 mm, using an ATtiny84 microcontroller and a DRV8834 stepper motor driver. Under this configuration, the image quality is surprisingly good, not only capturing beautiful images of the chips but also checking micron-level features, and even serving as a digital goniometer to measure contact angles.

Initially, this project was for a specific need, but Yuksel clearly realized that this could be a multifunctional photography system that anyone can assemble and use at home or school.

Yuksel’s leaders at IBM supported him in making the assembly instructions public, which is truly charitable. With just LEGO, a 3D printer, and a Raspberry Pi, one can create a microscope for scientific research, saving a lot of research funding.

However, when he began preparing the instructions, he was troubled by several issues.

He built the device using a state-of-the-art 3D printer and a fully equipped mechanical workshop. Moreover, the small stepper motors used are expensive and not available in general hobby electronics stores. Programming the ATtiny84 with a dedicated ISP programmer is certainly not as easy as programming a commercial Arduino board with a USB interface.

Therefore, Yuksel returned to the drawing board and redesigned everything using easily obtainable components, such as using Adafruit’s Arduino control board and stepper motor driver, as well as the 28BYJ-48 stepper motor, which can be found for just a few dollars anywhere. He also replaced the LED matrix light source with a more easily homemade and lower-cost version.

Afterward, he bought an LED backlight module from Adafruit for $3, along with a high-power LED. The intensity is slightly lower than the original LED matrix, but for both reflective and transmissive microscopes, the uniformity is still quite good. For the new linear actuator, Yuksel combined LEGO’s sliding parts with the rack and pinion combination he designed using FreeCAD’s gear toolbox and printed it using his personal Creality Ender 3 printer. The new design performed as well as the previous one, even better.

The instructions were written by the young man on Github, and interested students can go take a look~

Github link:

https://github.com/IBM/MicroscoPy

This device may actually have many areas for improvement, Yuksel hopes this prototype can inspire others to try new and better ideas.

So, can it replace laboratory microscopes? Perhaps not, but this microscope provides a great solution for schools with limited funding, which is why the assembly instructions are open-source, hoping to make it easy for everyone to access and enjoy.

The young man’s IBM homepage:

Related reports:

https://spectrum.ieee.org/geek-life/hands-on/build-a-sophisticated-microscope-using-lego-3d-printing-arduinos-and-a-raspberry-pi