We’ve seen plenty of unique implementations for solar panels, but none quite like these so-called VEIL Solar Shades from designer Büro North, which block out the sun’s rays just as well as they capture it. In addition to being light enough for a child to turn on a swivel (they’re designed specifically for schools), the shades would apparently also boast a pattern of LED lights on their undersides, which would indicate if they’re in the optimal position to gather the maximum amount of solar energy. No word as to when of if they’re actually going to put to use, but the project has apparently already received some funding by the Victorian Government in Australia, and it certainly seems like it’d find plenty of appeal beyond schoolyards.

(source: engadget)

[tags]solar,sustainable,energy,design,shades[/tags]

Another useful place for something like this would be the 8th floor module, which is currently used to pass data down from the 12th floor to the 4th floor. It is powered by a rechargeable battery pack. The Xbee radio chip is programmed to go into cyclic sleep, enabling maximum energy saving. It would be a good feature, to have the circuit detect the battery voltage going down, and having the xbee send out a signal before it dies, rather than just going silent.

For this reason, I’ve been playing around with the MAXIM 8212 voltage detector chip. Using the given solarbotics circuit. Doing a couple of tests to see which resistors (R2 and R3) I need in order to detect an input voltage level of 3.2-3.3. From the diagram in that pdf file, it seemed like R1=100k, R2 (trigger)=175K and R3 (hysterersis)=275K should do the trick. This triggers the load at a voltage of around 6V, and releases when it goes under 3.3V.

Now if I want the trigger to be around 3.5-3.7 (fresh battery) I need to place R2 = 200k. And to know that the battery’s power is ending (3.0-3.2 V), the hysterersis resistor value has to be R3 = 275k.

The 1381 IC is a voltage trigger. Using this IC in a circuit (I got the 1381S, which has a preset voltage trigger point at 4.0-4.3 V. I just wanted to try to make a simple BEAM circuit here, wakes up whenever it has enough voltage (4V in this case) to power the load. The 2N3904 is ***(goes ). Again here, I got a trigger from between 2.0 to 2.3V, half of what I’d expected.

Here are some of the measurements we got along the process:

• 2 magnets, 1 coil => 5-10mV
• 3 magnets, 1 coil => up to 20mV
• 6 magnets, 1 coil => around 50mV
• 3 magnets, 1 long coil (made up of 2 combined) => 40-50mV
• 3 magnets, 2 separate coils => 70-100mV
• 6 magnets (2 sets of 3), 2 separate coils => 150mV
• 8 magnets (2 sets of 4), 2 separate coils => 250-290mV
• 12 magnets (3 sets of 4), 2 separate coils => 300mV

What worked best in the end was to put 3 groups of 5 small magnets on the string, while having two separate coils of very thin magnet wire (the red one from radioshack). Each of those went into a rectifier (turns the AC current into DC), and with a capacitor in the circuit, gave us 1.8 V on average, definitely enough to light up at least four LEDs.

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In order to take this project forward, we need to figure out better materials for the pipe. Instead of the stiff plastic pipe we got, we might try to get a more flexible pipe, smaller in diameter. The curve was difficult for the magnets path, and there was a lot of friction. This can be solved with the proper materials. We both feel like it will be great to actually get something simple working, so will try to continue and at least be able to have documentation of a made prototype.

voltage: with a 10 uF capacitor, range between 1.5 to 2V
current: average of 20-30 mA while turning the faucet, reaching a maximum of 50mA.

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