[Colin] has put together an instructable for a solar power generator that uses the thermoelectric effect instead of the photovoltaic (PV) effect. We have seen Peltier devices used in cooling cans, solder paste, backs, and hacked hard drives. This is the first hack we have seen where a Peltier device is used to generate electricity from heat, essentially running the device backwards. The thermoelectric effect is the same principle that is used to generate electricity in radioisotope thermoelectric generators used in deep space probes such as Cassini. What applications can you come up with to use the thermoelectric effect as a power source?

We saw this pretty smooth solar tracker run by an Arduino. There aren’t many details, but we can see that it works well, and is in fact, run by an Arduino. We knew if we posted this that people would be commenting that the Arduino is overkill. We agree.  So this post is to ask, how would you do it? Give us links to the more efficient designs you have come up with. It doesn’t have to be a fully documented project, a schematic will do. We would probably go with something like a phototropic suspended bicore for simplicity and low power consumption.

[via littlebirceo]

in 1983, [Steve Roberts] packed up a Tandy 100 laptop and a 5-watt solar panel, fleeing suburbia on his recumbent bicycle on what would become a 17,000 mile journey that forever cemented his place in the geek pantheon…not just as a technology hacker, but as one of the preeminent “life hackers,” pursuing his own dreams on his own terms and inspiring others to do the same.

In this 1989 video, recently unearthed by Hack a Day, [Roberts] reflects on the first 16,000 miles of his voyage, detailing some of the technology that went into his then-current ride, the Winnebiko II.

Next time you’re comfortably working from the local park with your laptop tethered to a 3G connection, raise your latte in toast to [Roberts], who was pioneering the “mobile professional lifestyle” more than two decades ago. There was no Google Maps, no mainstream consumer internet, no 3G wireless. It was all packet radio and acoustic couplers on pay phones. Where he casually speaks of “living in the computer networks,” he’s referring to CompuServe, GEnie and UUCPNET. And next time you’re trapped at a green light while the driver ahead of you is distracted by text messaging, you can curse thank [Steve] for that, too…with his handgrip-integrated keyboard, he may well have invented texting while driving.

[Roberts] is still blazing trails…tinkering, writing, and living the “technomad” lifestyle, now by sea instead of land. You can follow along with his adventures on two web sites: microship.com is now primarily a retrospective of the past quarter century…the Winnebiko/BEHEMOTH bike projects and subsequent Microship trimaran, along with archives of his writings. nomadness.com looks ahead to “open-ended global voyaging” on his new vessel, the Nomadness. The site contains articles and reviews, photos, and his blog with current status updates. There’s also the Nomadic Research Labs Store, where you’ll find [Roberts’] own books, project surplus, and boating and electronic parts.

Though not much info is readly available about it on the web, [Joe Carruth] is trying to build publicity (and venture capital) for his home-built solar electric generator. At its essence, it is a Stirling dish system with an adjustable composite mirror surface. This means that instead of having to rotate the entire contraption in order to follow the Sun, [Joe] only has to make  the mirror segments pivot. A Stirling steam engine at the tip converts the energy into the movement used to generate electricity. Solar power plants (or ‘farms’) that are emerging are beginning to consider the advantages of using more efficient Stirling dishes rather than less efficient solar panels. If anyone has an idea as to how [Joe] can automate sun tracking for the mirrors, please post it in the comments. A couple more videos on the topic (in general) are available below:

Reader [unangst] pointed out to us an article in the U.K.’s Daily Mail, where a teenager from Nepal had managed to create a 9v, 18W solar panel using human hair rather than the usual semiconductors (usually crystalline-silicon). The complex silicon in solar panels are what keep the prices out of reach of developing nations, and while there are a number of new technologies that are helping  bring down the cost, [Karki] managed to make his solar panel for only £23 (roughly $38). He also claims that when mass produced the price could drop substantially down to under $10 a panel, which would shatter the $1/watt sweet spot.

The melanin in hair acts as an organic-semiconductor, and while the hair does not have the longevity that silicon panels have (months rather than years), these panels can be made cheaply and serviced with little to no complex knowledge. Using melanin as an organic semiconductor seems to be a newer idea, because information seems hard to come by, but we managed to find a research paper from 2007 that explored the energy absorption attributes of melanin, as well as some good background info for the science types.

Research Paper (Warning: PDF)

So, Hack a Day readers, which one of you is going to make your home-brew solar panels first? Let us know when you do.

Thanks [unangst].

Back in October we reported on the I-Swarm robotics project. [Travis] sent us some more information. These tiny robots are programmed optically and are able to respond to programming commands via an infrared signal. Locomotion is facilitated with piezoelectric actuators and the power to the units provided through a solar cell. It is not clear that this project is still ongoing as the I-Swarm web page lists a project termination date of 6/31/2008. That being said, the video embedded after the break was posted two days ago showing swarm movement and detailing the programming, testing, and hardware specifics.

[via Hizook]

We’ve already covered a pipe bomb mini-fridge this week, but inventor [Tom Chalko] provides us with today’s fridge hack. He noticed that chest-style (laying down, see above) freezers were more energy efficient when compared to normal stand up refrigerators at the same size, despite the colder temperatures involved. This is largely due to the fact that these chest-style freezers keep cold air in like water in a bowl, even if the lid is open. He has written a very thorough report on his findings (pdf), as well as a detailed walk through of the manageable task of converting a chest-style freezer into a chest-style fridge. In the end, his fridge only used 103 Wh of electricity on the first day to reach and maintain between 4° and 7° C (39° to 45° F), and he noted that 30% of that was just getting it up to temperature. After that, the fridge only turned on for roughly 90 seconds an hour, making it a very quiet fridge as well.

Strobit looks like it could be a project to keep an eye on. The entire project is open source, including the hardware. The aim is to build a low cost, low power, wireless enable arduino powered widget. This seems like it could really cut down on the development time of many projects we’ve seen here. Development is still ongoing but it looks like they’ve already implemented some mesh networking similar to the zigbee systems.

[via hackaday flickr pool]

[Aaron] a google employee came up with an idea that would be good for the environment, as well as fun. The Radish is a solar powered display, updated from a google calendar, with extremely low power consumption. They are building this to be an indicator of the conference room schedule. When we first read this, we wondered just how much greener it could possibly be than printing a few sheets of paper. Then we read that they were going through six reams per day. wow. The Radish gets its power through a solar panel, and preserves it through some creative power saving modes and the fact that it has an LCD that only requires power to update. Would this be a good place for some E paper? Data is transferred using IEEE 802.15.4, which is slow, but also more efficient in terms of power than normal WiFi. The system is so efficient, it can run for 3-4 days in low light conditions after a charge . Another cool fact is that [Aaron] got to design and build this on company time. Google allows people to spend 20% of their time on innovative new projects of their choice.

correction: the LCD goes into an extremely low power “sleep mode” when not being updated, and retains the last image loaded.

It sounds unbelievable, but it is true. You can harvest most of what you need for a simple solar cell from powdered donuts and tea. Powdered donuts have nanoparticles of titanium dioxide which is a “high band gap semi conductor”.  This means that it can be used to make solar cells. The tea is simply used to dye the material so it can pick up the visible spectrum. The process is a bit too involved to be something you would just toss together in the field, but it’s cute nonetheless.

[Knut Karlsen] put together a prototype set of solar rechargeable batteries. He always seemed to have batteries laying around on his worktable and figured they might as well be charging. The flexible solar cells were given to him by researchers at the IFE and are rated at 1.8V. He used superglue to secure them to the C cells. A silver conductive pen plus flat wires from a Canon lens connect the solar cells to the battery terminals. The batteries just trickle charge for now, but he’s going to try to build cells with built in charge controllers in the future.

[dark sponge] decided to make his DS lite, solar powered. Or, at least charged via solar panels.  He was able to find solar cells that were 60×60 mm, which means he could fit 4 of them on the outside of the DS. This gives him a total of 6V at 80 mA output. These panels charge the battery between uses. The DS has to be open and laying on its face for all 4 panels to be exposed, but this way of mounting them didn’t alter the pocket-ability of the unit. He says he’s been using it for a while and hasn’t had to plug it in yet, but we have concerns about wiring the panels directly to the battery. As [cyrozap] points out in the comments on the instructable, this is a Lithium Ion battery, shouldn’t there be some charging circuitry involved?

The 25th Chaos Communication Congress is underway in Berlin. One of the first talks we dropped in on was [script]’s Solar-powering your Geek Gear. While there are quite a few portable solar products on the market, we haven’t seen much in the way of real world experience until now.

[script] selected a four segment folding solar panel after some research. He pointed out that solar is currently more of a necessity technology than money saving since the panels can be very expensive. For connectors, he recommended ones that were safe, polarized, and difficult to short, like the RIA connect 230 series he used. Most of the device plugs were easily purchasable, but some had to be salvaged from old AC adapters. A key component of his setup was the adjustable voltage regulator. It’s based on the LTC3780 buck-boost controller which is 98% efficient and can be adjusted from 4V to 25V.

[script] covered some of the problems he ran into in use. The first was an Nokia that refused to charge until a resistor was added to reduce the current delivered. Less sensitive devices like portable peltier fridges will work without any issue. For laptop use, he ran into problems with demand spikes killing the power delivery. He added a large cap normally used in car audio systems to make power delivery more consistent. Laptops can consume as little as 15W during normal use, but when they’re charging the battery, the draw can jump to 50W. On his ThinkPad, he was able to turn off charging to prevent this. He monitored the performance of the panel by building a Kill A Watt style device using an ATmega8 to measure current and voltage and log it to EEPROM.

In conclusion, [script] stated that he was happy with his experience, but that it was still impractical to use the portable panel in anything other than direct sunlight.

Have a room in your house that really could benefit from some sunlight? Build a Suntrack to reflect light in as long as possible. The two axis motor set up is built from a couple of  satellite dish positioning motors with the control electronics removed. The whole thing is controlled with a PIC 18f2520.  Once calibrated, it will reflect the sun into your room, updating every twenty seconds. While this may not be the most efficient way of lighting a room, it is a cool way to do it if you absolutely must have sunlight. We can’t help but wonder if there would be a way of using a solar powered system to do this to save energy. Could this possibly be done using BEAM “head” circuit?

[via Hacked Gadgets]

Our love for solar projects continues on with this method to make your own solar panels. [Mike] built a 60 watt solar panel from individual solar cells he purchased off eBay. Procuring parts off of eBay normally causes others hardship when they try to duplicate the project, however in this case there are so many types of cells people can use to produce their own unique solar panel. Even cells that are extremely damaged my still be used, as in this example. To charge a 12 volt battery the number of cells in series just needs to be 16-18 volts, and the rest in parallel will supply more current. Charging a battery without a charge controller is not recommended, but commercial ones are easily had. Those not interested in jumping all the way in with solar may want to test the waters by building their own panel and putting it to use as a charging station for your portable gadgets.