Cathode ray tubes (CRTs) are a fascinating display technology that has been largely abandoned outside of retro gaming and a few other niche uses. They use magnets to steer a beam of electrons rapidly across a screen, and while a marvel of engineering for their time, their expense, complexity, and weight all led to them being largely replaced by other displays like LCDs and LEDs. They were also difficult to miniaturize, but there were a few companies who tried. [dooglehead] located a few of the smallest CRT displays he could find and got to work putting them in the most unlikely of situations: a virtual reality headset.
The two displays for his headset come from Sony Watchmans, compact over-the-air black-and-white handheld televisions from the late 1900s. [dooglehead] had to create a method for sending video to these units which originally had no input connections, and then also used an FPGA to split a video signal into two parts, with one for each display. The two displays are placed side by side and attached to a Google Cardboard headset, with an off-the-shelf location tracker attached at the top. An IMU tracks head rotation while this location tracker tracks the motion of the unit through 3D space.
With everything assembled and ready to go, the CRT VR headset only weighs in a few grams heavier than [dooglehead]’s modern HTC headset, although it’s lacking a case (which is sorely needed to cover up the exposed high voltage of the CRTs). He reports surprisingly good performance, with notable interlacing and focus issues. He doesn’t plan to use it to replace any of his modern VR displays anytime soon, but it was an interesting project nonetheless. There are some rumors that CRTs are experiencing a bit of a revival, so we’d advise anyone looking to toss out an old CRT to at least put it on an online market place before sending it to a landfill.
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