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Background info on light project

Light: prototype

Info on solar components,
more links and resources

Light Controller/Light Switch

Prototype

Photos:

Link to quicktime movie - footage of it in action

more info on initial concept

More info coming soon...

Details:

Circuit & electronics:
• PIC code

More info on el strips and the circuit coming soon...

Notes:
El wire, el panels, etc. is relatively easy to use, but expensive. It took us a little bit of effort to spec out our parts. The vendor we were in touch with somewhat sent us down a stray path. Here are some basics: you will need an inverter for each piece (panel, wire, etc.) that you are individually controlling. The power required is dependent on the square footage of light. We were able to find el strips at All Electronics for a reasonable price, but had to go with the 1x5" strips they had in stock. We busted a few inverters, but aside from that, putting together our circuit was straightforward. Our circuit is relatively simple: el strip to inverter to relay to pic, and one set for each el strip. We have a pot attached to the circuit. Position of the pot determines which lights are on/off. The pot is attached to a fly wheel and the two strings for the shade. We are using two power circuits because the el strips draw a lot of amperage. Each one draws about .1 A. The voltage at the input of the inverter is 5V -- output is 85V. Each strip can run on up to 10V -- if we went with a higher power source, we could get brighter strips. Altogether, that's can be quite a shock. We were careful to hide and shield our components in the shade.

Dimming el panels: some vendors sell dimmers, but they are very expensive (over $100++.) Tom helped us hook up an AC dimmer to an el strip. We only got about 15% variation -- not very noticeable. Little payoff for big effort. This is what I've also heard from other people who've tried to dim el panel.

We made as many of our components easy to access to fix, etc. For example, we sealed the wiring to the shade in paper flaps that we can open and close, soe we can access the wires. We made slots in the shade (like film holder strips), so we can interchange the image on our shade. Our wall and and shade holder are velcored to our frame so we can access that.

Most shades have pretty cheap little plastic handle/knobs. We chose metal because it has a nice visual and tactile quality, and went with a simple grooved design 1) one set for turning the light on/off 2) another simulating the up/down of the shade. The "dimming" ones (see photo): 1) the one that turns the lights on has skinny grooves/wide bands (the way the shade looks when its on) 2) the one that turns it off has the pattern in reverse. For opening and lowering the shade, we have a wide groove on the top or bottom end, depending on the direction, that act as tactile directional arrows.

The Juki is a pain in the ass to use. I've been sewing for 20 years -- and can say, that machine is a beast. I ended up manually sewing the sleeve. The plastic sleeves are too thick, so I couldn't use my Kenmore.

Next steps:
Solar power: I'd love to make this solar powered, especially since these sit in a window. Got some info from Gary Shroeber about power shunts, and know basic circuit. Need to spec out solar panels and rechargeable battery.

Cutouts: I got some 4 ply paper cut out with some patterns on the laser cutter. however, it's too thick to fit in our sleeves. I need to fiind a thinner paper that is opaque. The sleeves are pretty tight. I tried stenciling transparencies with the cutouts, but it's too messy. Another option is to find a printer who can print white ink on the transparency -- but this might be too expensive. I'd prefer the inserts to be white (using white ink, or cutting out white paper.) That way, the shade appears white when it's off, and there's also an element of surprise when the shade is turned on.

Solar power:
I need to remake the shade so the backside is transparent, allowing the solar cell to be exposed to the sun. right now the material is semi-transluscent, which would block some of the rays. I found and bought some thin flexible solar panels that will fit into the shade in the back panel. I've done some intiial work of adding solar cells and a rechargeable battery to the circuit, so the solar cells can partially power the circuit. I've been collecting some data on its efficiency. Right now, it doesn't draw enough power from the solar cells to fully power the circuit. More info on this coming soon...

Info on solar component, more links and resources

Circuit diagrams:
window shade
window shade with solar cells & rechargeable battery
solar cells & rechargeable battery