DIY Laser Scanning Microscope
Urs Gaudenz's homemade laser scanning microscope was built from DVD heads.
Laser scanning microscopes use a focused light beam to scan a sample, rather than an array of tiny image sensors that you might use in a traditional camera. As this light beam can be tightly controlled, the resolution of images acquired by such a setup can produce details at a very small scale – e.g. cellular images, or closeups of sensitive electronics.
One might think that such an instrument is well out of the price range of amateur experimenters, but as it just so happens, precision laser emitter/receiver/staging apparatuses are actually quite common, in the form of optical media readers. To make his own laser scanning microscope, microengineer Urs Gaudenz employed pickup heads from two DVD players.
One head uses its actual laser to illuminate the sample at a tiny spot, and receives illumination feedback via a photodiode. Its linear actuator is used to move with respect to the sample in the x-axis. The other head is tasked with moving the sample itself in the y-axis to obtain an image pixel-by-pixel.
The device is based on an Arduino Micro, along with a PCB used to hold the DVD units and assist with wiring. Processing is used to produce actual images from the acquired data. More info and images can be found in Gaudenz's project write-up, and code and PCB information is available on GitHub.