Big Power, Little Power, Tiny Power, Zap!

Our Hackaday Prize Challenges are evaluated by a panel of judges who examine every entry to see how they fare against judging criteria. With prize money at stake, it makes sense we want to make sure it is done right. But we also have our Hackaday Prize achievements, with less at stake leading to a more free-wheeling way to recognize projects that catch our eye. Most of the achievements center around fun topics that aren’t related to any particular challenge, but it’s a little different for the Infinite Improbability achievement. This achievement was unlocked by any project that impressed with their quest for power, leading to some overlap with the just-concluded Power Harvesting Challenge. In fact, when the twenty Power Harvesting winners were announced, we saw that fourteen of them had already unlocked the achievement.

Each of the Power Harvesting winners will get their own spotlight story. And since many of them have unlocked this achievement, now is the perfect time to take a quick tour through a few of the other entries that have also unlocked the Infinite Improbability achievement.

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High Efficiency, Open-Sourced MPPT Solar Charger

A few years ago, [Lukas Fässler] needed a solar charge controller and made his own, which he has been improving ever since. The design is now mature, and the High Efficiency MPPT Solar Charger is full of features like data logging, boasts a 97% efficiency over a range of 1 to 75 Watts, and can be used as a standalone unit or incorporated as a module into other systems. One thing that became clear to [Lukas] during the process was that a highly efficient, feature-rich, open-sourced hardware solution for charge controllers just didn’t exist, at least not with the features he had in mind.

Data logging and high efficiency are important for a charge controller, because batteries vary in their characteristics as they recharge and the power generated from things like solar panels varies under different conditions and loads. An MPPT (Maximum Point Power Tracking) charger is a smart unit optimized to handle all these changing conditions for maximum efficiency. We went into some detail on MPPT in the past, and after three years in development creating a modular and configurable design, [Lukas] hopes no one will have to re-invent the wheel when it comes to charge controllers.

Open Hardware Takes Charge in Papua New Guinea

You probably don’t think much about charging your phone. Just find an outlet, plug it in, and wait a while. Can’t find a cable or wall wart? A rainbow of cheap, candy-colored options awaits you down at the brightly-lit corner drugstore.

This scenario couldn’t be further from reality in third world countries like Papua New Guinea, where people living in remote jungles have cell phone coverage, but have to charge their phones by hooking them up directly to cheap solar panels and old car batteries.

[Marius Taciuc] wants to change all of that. At the suggestion of his friend [Brian], he designed an intermediary device that takes any input and converts it to clean 5 volts with a low-cost, reliable buck converter. The inputs are a pair of alligator clips, so they can be connected to car battery terminals, bare-wire solar panel leads, or 9V connectors.

Mobile phones mean so much to the people of Papua New Guinea. They’re like a first-world care package of news, medical advice, and education. At night, they become simple, valuable lanterns. But these dirty charging hacks often lead to house fires. Someone will leave their phone to charge in the morning when they go off to hunt, and come home to a pile of ashes.

This is an open, simple device that could ultimately save someone’s life, and it’s exactly the type of project we’re looking for. [Marius] hopes to see these all over eBay someday, and so do we. Charge past the break to see [Marius] discuss the Brian Box and the people he’s trying to help.

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Hackaday Prize Entry: Arduino MPPT Controller

Imagine you’re building a small solar installation. The naive solution would be grabbing a solar panel from Horror Freight, getting a car battery and AC inverter, and hoping everything works. This is the dumb solution. To get the most out of a solar you need to match the voltage of the solar cell to the voltage of the battery. How do you do that? With [Debasish]’s entry for The Hackaday Prize, an Arduino MPPT Solar Charge Controller.

This Maximum Power Point Tracker uses a buck converter to step down the voltage from the solar cell to the voltage of the battery. It’s extremely efficient and every proper solar installation will need a charge controller that does something similar.

For his MPPT, [Debasish] is using an Arduino Nano for all the math, a DC to DC buck converter, and a few MOSFETs. Extremely simple, but [Debasish] is connecting the entire controller to the Internet with an ESP8266 module. It’s a great example of building something for much less than it would cost to buy the same thing, and a great example for something that has a chance at making the world a little better.

 


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Beach Buddy is a Boombox, Phone Charger, and Sunburn Warner

The Beach Buddy

When you venture out onto the beach for a day in the sun, you’re probably not preoccupied with remembering the specifics about your sunscreen’s SPF rating—if you even remembered to apply any. [starwisher] suffered a nasty sunburn after baking in the sunlight beyond her sunscreen’s limits. To prevent future suffering, she developed The Beach Buddy: a portable stereo and phone charger with a handy sunburn calculator to warn you the next time the sun is turning you into barbecue.

After telling the Beach Buddy your skin type and your sunscreen’s SPF rating, a UV sensor takes a reading and an Arduino does a quick calculation that determines how long until you should reapply your sunscreen. Who wants to lug around a boring warning box, though?

[starwisher] went to the trouble of crafting a truly useful all-in-one device by modifying this stereo and this charger to fit together in a sleek custom acrylic enclosure. There’s a switch to activate each function—timer, charger, stereo—a slot on the side to house your phone, and an LCD with some accompanying buttons for setting up the UV timer. You can check out a demo of all the Beach Buddy’s features in a video below.

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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

Boost Peak Power Tracking Battery Charger

[Rusdy] is building a solar charger for his electric bike, and quickly realized the lithium cells in his bike wouldn’t work well with the most common charge controllers out there. Solar cells have an IV curve, of course, and this changes with the amount of sunlight, requiring some conversion circuitry. Most of the charge controllers out there operate in buck mode, but the commercial boost mode converters [Rusdy] needed for his 36V battery are pricey as all get out. What was [Rusdy] to do? Build his own Boost MPPT solar charger, of course.

The circuit used for the charge circuit is fairly similar to a boost converter, with a little bit of logic required to get the maximum power out of the solar cells. [Rusdy] had an Arduino lying around, so that took care of the logic, and by sampling the voltage and current with the analog pins, he can turn a MOSFET on and off to get the most out of his solar cells.

The finished product works perfectly with an efficiency greater than 87%. Charging current and the final trickle charge is adjustable through software, allowing [Rusdy] to get the most out of his solar panels and electric bike. The board itself is just a prototype and could use a layout revision, but we’ve got to hand it to him for cloning a >$300 charge controller with an Arduino and a few scraps in a part drawer.