Turrell Clone
There is an artist named James Turrell that I really like. Many years back I saw some of his Tall Glass series at a gallery in Santa Monica and was entranced. The things cost more than a house so I was happy just to look. I spent some time looking at how he does his magic and thought some day I would try and make one.
This is a time lapse of my last iteration. the color changing is sped up by a factor of about fifty. It's a (Small) Large Glass about 3 feet tall rather than his six feet tall. But it gets the idea across. The color plane is interesting because it doesn't look like a surface. Turrell figured out a few clever tricks which I copied to get the effect.
The hardest part of the piece was getting the slow smooth color changes. I believe that he does it with talented programmers and individually addressed LED strips. I hate programming so I kept playing with easier ideas. The closest was a commercially available three channel LED driver. It was about 60% of the effect I wanted. However it only does ROTGBIV, no whites. And it's too fast.
A few weeks back I got an idea to do the whole thing analog. The idea was great and worked out very well. I have nine channels. Each uses a very slow triangle generator chip that goes into a non-inverting op amp with level shifting. The resulting slow triangle goes into the gate of a MOSFET that dives the channels. The important idea is that each channel has a different sized timing capacitor and all the capacitors can't be identical. So I end up with a three channel RGB LED string that is constantly falling out of sync. Thus the color combinations don't really repeat.
It's really fun to watch. I know that Turrell's artworks go slower than this unit. And I may increase the capacitance values to go even slower. But it's really nice right now to just sit and watch.
Oh and the price is much less than an original. Even with all the false tries it used about 300$ in funds. To make another would be much less.
Cheers.
Turrell Clone
There is an artist named James Turrell that I really like. Many years back I saw some of his Tall Glass series at a gallery in Santa Monica and was entranced. The things cost more than a house so I was happy just to look. I spent some time looking at how he does his magic and thought some day I would try and make one.
This is a time lapse of my last iteration. the color changing is sped up by a factor of about fifty. It's a (Small) Large Glass about 3 feet tall rather than his six feet tall. But it gets the idea across. The color plane is interesting because it doesn't look like a surface. Turrell figured out a few clever tricks which I copied to get the effect.
The hardest part of the piece was getting the slow smooth color changes. I believe that he does it with talented programmers and individually addressed LED strips. I hate programming so I kept playing with easier ideas. The closest was a commercially available three channel LED driver. It was about 60% of the effect I wanted. However it only does ROTGBIV, no whites. And it's too fast.
A few weeks back I got an idea to do the whole thing analog. The idea was great and worked out very well. I have nine channels. Each uses a very slow triangle generator chip that goes into a non-inverting op amp with level shifting. The resulting slow triangle goes into the gate of a MOSFET that dives the channels. The important idea is that each channel has a different sized timing capacitor and all the capacitors can't be identical. So I end up with a three channel RGB LED string that is constantly falling out of sync. Thus the color combinations don't really repeat.
It's really fun to watch. I know that Turrell's artworks go slower than this unit. And I may increase the capacitance values to go even slower. But it's really nice right now to just sit and watch.
Oh and the price is much less than an original. Even with all the false tries it used about 300$ in funds. To make another would be much less.
Cheers.