I built a projector out of a 15” lcd panel (lumenlabs plans) beforehand, was thinking of new uses for it and stumbled across the multi-touch stuff. I plan on builting an FTIR setup, but the compliant surface thing kind of bugs me so I was looking into using DI. Seems the major problem with DI is getting even illumination.
A simple view of the optics of the lumenlab diy projector:
Reflector | bright light source (omnidirectional IIRC) | glass sheet as a heat shield | fresnel lens to collect light and make them parallel | lcd monitor | fresnel lens to collect light and focus on a single point | projection triplet lens to magnify the image|
I got to thinking, why not use a fresnel lens above a bright IR point light to make the light even? I’m not sure if this is even possible, since you have to worry about camera placement which would probably have to be above the fresnel lens.
I included an image from the lumenlabs guide.
The light source could be IR, for evenly illuminting a DI setup. Acrylic fresnel lenses can be bought online and are not that expensive.
If this has been mentioned before then nevermind.
