Hi everyone. I’m starting this thread to track my project throughout it’s construction and developement and share ideas along the way.
My MT goal is to build an app to play music files with. Not just play it, but run it through virtual modules to phase shift, reverb, LFOs etc. It will also have mixing capabilities just ike DJ hardware with a virtual mixing and effects console. The real world version of this requires mulitple fingered changes to knobs and sliders so, we figured the MT interface would lend itself to acheiving that goal on screen. I have a software engineer friend here that’s helping with code and I’m taking care of hardware. We’re both live sound engineers so I’m sure as we go along in developement, we’ll dream up more ways to manipulate sound.
Here’s the initial specs of my setup:
Screen size: 22” x 16.5” .250” cell cast acrylic, edges beveled @ 45 degrees and polished
Illumination: FTIR with 88 IR LEDs @16 mW radiant power = 1.4 watts total
Camera: Modified Logitech webcam (IR filter removed) with 3 layers exposed film as visible light filter
Projector: Proxima Ultralight SV1+ 700 lumens, 300:1 contrast ratio
I’m still working out what to use as a projection screen Probably Rosco grey.
I’m experimenting with an idea to help with making the surface more compliant. I read here that people have tried many things, and it seems that silicone or PVC in some form does well.
Yesterday, it dawned on me that a coat of PPG automotive clearcoat to the acrylic might work well. I can add a “flexiblizer” to the mix and it will cure with a little more give to it. It might just work as a zero pressure surface. There is a bonus as well. If it gets scratched, I can just sand the clearcoat lightly and spray on another, fresh layer.
I’m going to try this to a small MT setup I have to experiment with. It’s an 8” x 10” mini MT. The first one most of us built. ( : Now I use it to test out ideas and materials.
I have my $158 projector on the way, as well as LEDs and resistors. Not much tech stuff here on Maui so I use the internet to get my parts and supplies. I have a local plastics shop cutting and polishing my 24” x 18.5” x .250” acrylic. It’ll cost about $40 cut, beveled and polished!
Why the bevel? Because it refracts the incoming light in a way that bounces it around more due to the steep angle. In other words, there are more points of reflected light in a given area. That means that when the surface is touched, there are lots of light rays to bounce off the surface and reflect IR light back at the camera.
I used this very handy applet to show the light reflection angles.
My setup has the LED angle at 0, the beam spread at 22 degrees, edge angle at 45 degrees, LED position at 75. Set it up that way and you’ll se the advantage over straight into a 90 degree edge!
More to come!