The Phidgets Solar Powered Weather Station

weather

Yes, it’s a weather station, one of those things that records data from a suite of sensors for a compact and robust way of logging atmospheric conditions. We’ve seen a few of these built around Raspberry Pis and Arduinos, but not one built with a Phidget SBC, and rarely one that has this much thought put in to a weather logging station.

This weather station is designed to be autonomous, logging data for a week or so until the USB thumb drive containing all the data is taken back to the lab and replaced with a new one. It’s designed to operate in the middle of nowhere, and that means no power. Solar it is, but how big of a solar panel do you need?

That question must be answered by carefully calculating the power budget of the entire station and the battery, the size of the battery, and the worst case scenario for clouds and low light conditions. An amorphous solar cell was chosen for its ability to generate power from low and indirect light sources. This is connected to a 12 Volt, 110 amp hour battery. Heavy and expensive, but overkill is better than being unable to do the job.

Sensors, including temperature, humidity, and an IR temperature sensor were wired up to a Phidgets SBC3 and the coding began. The data are recorded onto a USB thumb drive plugged into the Phidgets board, and the station was visited once a week to retrieve data. This is a far, far simpler solution than figuring out a wireless networking solution, and much better on the power budget.

Via embedded lab

Solar power for your bike

After the headlight on his bike died, [Patrick] decided this was the best time to hack the remains and solve a few problems: namely a constantly drained battery from accidentally forgetting to turn the light off. He opted for a solar solution, as he already had both an Adafruit solar lithium charger and a Seeed Li-po Rider. [Patrick] picks the Adafruit board for its extra safety features like temperature sensing to prevent the cell from overheating.

The build uses 9 eBay-sourced 2V mini solar panels attached neatly on the bike’s mudflaps. Three groups of 3 panels in series provide the needed 6V into the Adafruit lithium board which safely charges a spare 900mAh Nokia phone battery from the junk drawer. [Patrick] admits this solar setup may be overkill. He decided to include a USB jack to keep his phone charged for some Google maps navigation. The Adafruit board does not step up to 5V, however, so [Patrick] tacks on a Mintyboost kit to kick the Lipo’s output up high enough to charge the phone.

Solar’s not the only alternative way to power your bike’s lights. Check out the RattleGen from earlier this year if you missed it.

Boominator solar stereo keeps the music pumping even in cloudy weather

Despite 40-some years of product improvements, boomboxes today still require a half dozen D-cell batteries and measure their life in single digit hours.  After this, the batteries get chucked in the trash. Tired of the absurd cost and quantity of batteries required in a typical boombox, reddit user [anders202] has whipped up a solution that will keep the party going and the landfills empty. Using some off-the-shelf components and some impressive woodworking skills, he created the “Boominator”.

Despite its environmentally-conscious design, this green machine packs a whallop. Using its dual 10W solar panels, it can drive four woofers and tweeters to produce an estimated 102dB of sound with power to spare.  This extra juice can be used to charge its two internal 7.2Ah batteries or a cellphone using the integrated USB charging ports.  Better still, Anders chose amorphous solar panels (as opposed to crystalline) which produce power even in cloudy weather as demonstrated during a cloudy day at the Roskilde festival in Denmark.  For more information, check out the reddit comment thread.

Video demo after the jump

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Hardware store goods and an mbed combine help solar panels track the sun

sun-tracking-solar-panels

If you have the space, and can build a tracking rig cheaply you’ll be able to get a lot more out of your solar panels. That’s because they work best when the sun’s rays are hitting them perpendicular to the surface and not at an angle. [Michael Davis] hit both of those stipulations with this mbed powered solar tracker.

At a garage sale he picked up an antenna motor for just $15. The thing was very old, but still wrapped in the original plastic. It’s beefy enough to move his panels, but he first needed a way to mount everything. After checking his angles he built a base out of wood and used galvanized water pipe as an axle. Cable clamps mate his aluminum angle bracket frame to the pipe. This frame holds the panels securely.

To track the sun he used two smaller cells which aren’t easy to pick out in this image. They are monitored by the mbed microcontroller which measures their output in order to point the assembly in the direction which has the most intense light. A couple of limit switches are included to stop the assembly when it reaches either side.

This technique of using small solar cells as the tracking sensors seems to work well. Here’s another project that took that approach.

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$4 volt meter from a dollar store pedometer

[Paulo]’s got a few solar panels on his shed, and while he does have a fairly nice setup with a battery charge controller, he found himself looking around for a panel voltmeter. Of course you can buy a panel voltmeter for under $20, but [Paulo] wanted something that fit his 4-4-4 plan; his voltmeter should cost under $4, draw less than 4mA, and last for 4 years. The jury is still out on the 4 year qualifier, but he did manage to meet his other goals by repurposing a dollar store pedometer as a voltmeter.

The pedometer in question is a very simple device. After inspecting the PCB, [Paulo] found it operates by looking at a trigger pin and incrementing the number on the display each time the circuit closed. [Paul] designed a very small PIC12F-powered circuit that reads the voltage of his batteries and triggers the pedometer’s LCD for every 10th of a volt. To display 12.6 Volts, [Paulo]’s code triggers the LCD 126 times, for example.

After wiring up the reset button so the display will go back down to zero for each new reading, [Paulo] encased his new volt meter in a plastic box. It’s not exactly a fast way of measuring voltage, but seeing as how that won’t change very fast, it’s the perfect solution for [Paulo]’s solar charger setup.

How to make that old satellite dish cook all your meals

Grab that old satellite dish out of the dark corner of you garage and get those hot dogs ready. [Share alike license] is going to show us how to turn the dish into a solar cooker.

Harnessing the sun’s power requires a reflective surface. Although the image above makes it look like a mirror finish, this is really just covered in foil tape. This is what’s used to seal duct work and can be had for a few bucks at any home store. You’ll notice the dish is pointed up quite a bit more than it would have been when receiving satellite television. The mount on the back of the dish has been turned 180 degrees to allow for this. You want the rays to be focused on the bottom of the cooking area instead of the side and this will do the trick. A small grate was added just below the pinnacle of the receiver tripod. For now it has only been used to boil a pot of water. We’d like to see it grilling up some dogs but you’ll have to figure out a way to catch the drippings. We wonder if a transparent baking pan would block too much of the heat energy?

This is a great way to add purpose to neglected equipment. But if you’re serious about solar cooking you need something more along these lines.

Upgrading a solar lamp to charge an iPad

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[Phillip] and the crew at Voltaic Systems took a look at the Sunnan solar powered desk lamp from IKEA a while back, and while they thought it was pretty useful, there were definitely some things they wanted to change.

First on their list of revisions was to increase the capacity of the stock battery pack. Taking the lamp apart and unscrewing the pack’s lid revealed a set of 3 AA cells, which they swapped out for higher-capacity models with more than double the watt-hour rating.

A beefed up battery is a good start, but the lamp’s tiny solar panel has no hope of topping off the batteries outside of Death Valley. To ensure that they get a nice full charge, a small jack was wired into to the battery pack, allowing the group to connect any size external solar panel they pleased.

Finally, [Phillip] and Co. wanted the ability to charge an iPad2 from the lamp’s battery pack. They hacked in a small USB connector and a slightly modified MintyBoost board to provide a little extra juice to their tablet.

While they are still testing the modifications, they say that everything is working nicely, citing that the extra battery capacity and charging abilities are a great addition.