Three students from the University of Belgium have created a touchscreen system using the legacy CRT monitor and a glove fitted with phototransistors. They have named their system CRTouch and their setup revolves around an Altera DE2-70 development board.
The system works by using the phototransistors at the end of the index and middle finger to detect the beams emitting from the electron gun within the CRT. The Altera board controls the monitor and receives the sensor information. Using this information they can create images on the monitor that replicates a touch screen effect.
The Altera DE2-70 board integrates various components together making it useful for experiments and college laboratories courses exploring logic circuits and computer organization. The board includes toggle and push button switches, LEDs, 7-segment displays, SSRAM, SDRAM, Nios II processor, simple I/O interfaces, standard video and signal connectors, and USB and Ethernet connections.
Their system also includes a couple additional options to interact with the touchscreen. Using the middle finger sensor you can change the color of the content being drawn and also use an eraser tool to erase content already drawn. Their system is clearly a working prototype, as it currently shows off its many problems. The first one being detecting the position of the photosensor when the screen display is filled with dark colors, and the second one being picking up to many signals when the screen is a very light color. Even if they refine their system, I do not think CRT monitors are coming back.
This reminds me of the Nintendo Super Scope video game "gun." It would work by timing how long it would take the electron gun, in the CRT, to refresh the area on the screen where the gun is pointed. The avoid detection problems, the game would lighten up the screen each time the trigger was pulled. Perhaps the Belgium team could benefit from some 1980s-90s Nintendo techniques.
Eavesdropper
