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.
It seems that the longer a technology has been around, the more likely it is that all of the ideas and uses for that technology will be fleshed out. For something that’s been around for around 5500 years it must be especially rare to teach an old dog new tricks, but [Sebastian] has built a sundial that’s different from any we’ve ever seen.
Once done with all of the math for the sundial to compute its angles and true north based on his latitude and longitude, [Sebastian] used Autodesk Inventor to create a model. From there it was 3D printed, but the interesting part here is that the 3D printer allowed for him to leave recesses for numbers in the sundial. The numbers are arranged at such angles inside the sundial so that when it’s a particular hour, the number of the hour shines through the shadow of the sundial which creates a very unique effect. This would be pretty difficult to do with any machine tools but is easily accomplished via 3D printing.
[Sebastian] wanted a way to appreciate the beauty of time, and he’s certainly accomplished that with this new take on the sundial! He also wonders what it would be like if there was a giant one in a park. This may also be the first actual sundial build we’ve featured. What does that mean? Check out this non-pv, sun-powered clock that isn’t a sundial.
Thanks to [Todd] for the tip!
The simplest and easiest way to charge a battery with a solar panel is to connect the panel directly to the battery. Assuming the panel has a diode to prevent energy from flowing through it from the battery when there’s no sunlight. This is fairly common but not very efficient. [Debasish Dutta] has built a charge controller that addresses the inefficiencies of such a system though, and was able to implement maximum power point tracking using an Arduino.
Maximum power point tracking (MPPT) is a method that uses PWM and a special DC-DC converter to match the impedance of the solar panel to the battery. This means that more energy can be harvested from the panel than would otherwise be available. The circuit is placed in between the panel and the battery and regulates the output voltage of the panel so it matches the voltage on the battery more closely. [Debasish] reports that an efficiency gain of 30-40% can be made with this particular design.
This device has a few bells and whistles as well, including the ability to log data over WiFi, an LCD display to report the status of the panel, battery, and controller, and can charge USB devices. This would be a great addition to any solar installation, especially if you’ve built one into your truck.
This is [Debasish]’s second entry to The Hackaday Prize. We covered his first one a few days ago. That means only one thing: start a project and start documenting it on hackaday.io
Most of our energy comes from dead algae or dead ferns right now, and we all know that can’t continue forever. The future is by definition sustainable, and if you’re looking for a project to change the world for this year’s Hackaday Prize, you can’t do better than something to get the world off carbon-based fuels.
The simplest solar builds can be as fun as a redneck hot tub – a solar thermal water heater repurposed into a heated swimming pool with the help of a pump and JB Weld. You can even build a hose-based version for $100. They can be as useful as a Maximum Power Point Tracking charger for a solar setup – a few bits of electronics that ensure you’re getting the most out of your solar cells. You can, of course, access solar power in a roundabout way with a wind generator built from a washing machine and a 555 timer.
Getting energy from the sun is one thing, and putting it to use is another thing entirely. We spend a lot of energy on transportation, and for that there’s a solar power bike, an electric scooter, or a completely open source electric car.
Building the machines that make sustainable energy possible or even just the tools that will let us use all that energy are just a few ideas that would make great entries for The Hackaday Prize. You could go another direction and build the tools that will build and maintain these devices, like figuring out a way to keep these batteries and generators out of the landfill. Any way you look at it, anything that actually matters would make a great entry to The Hackaday Prize.
[Carl] recently upgraded his home with a solar panel system. This system compliments the electricity he gets from the grid by filling up a battery bank using free (as in beer) energy from the sun. The system came with a basic meter which really only shows the total amount of electricity the panels produce. [Carl] wanted to get more data out of his system. He managed to build his own monitor using an Arduino.
The trick of this build has to do with how the system works. The panel includes an LED light that blinks 1000 times for each kWh of electricity. [Carl] realized that if he could monitor the rate at which the LED is flashing, he could determine approximately how much energy is being generated at any given moment. We’ve seen similar projects in the past.
Like most people new to a technology, [Carl] built his project up by cobbling together other examples he found online. He started off by using a sketch that was originally designed to calculate the speed of a vehicle by measuring the time it took for the vehicle to pass between two points. [Carl] took this code and modified it to use a single photo resistor to detect the LED. He also built a sort of VU meter using several LEDs. The meter would increase and decrease proportionally to the reading on the electrical meter.
[Carl] continued improving on his system over time. He added an LCD panel so he could not only see the exact current measurement, but also the top measurement from the day. He put all of the electronics in a plastic tub and used a ribbon cable to move the LCD panel to a more convenient location. He also had his friend [Andy] clean up the Arduino code to make it easier for others to use as desired.
In need of a jacuzzi to complete your backyard but just don’t have the cash? Need a swimming pool for the little ones but tired of the cheap plastic ones popping and leaking all over the place? Look no further than [inexplorata]’s self-explanatory “Hippie-Redneck Solar-Heated Kiddo Swimmin’ Pool And Hot Tub“.
The pool uses a six-foot-diameter metal stock tank, provided by a neighbor. After some liberal use of JB Weld, the tank functions as a makeshift pool on the cheap, but the magic doesn’t end there. [inexplorata] found a solar thermal water heater that someone was getting rid of and snagged it to heat up the water, which is almost a necessity for most parts of the Northern Hemisphere right now.
A sump pump in a bucket handles water circulation, and [inexplorata] points out that the single water heater is more than enough to keep the water nice and warm (“hot enough to poach a rhino” is the scientific term used on the project page) so if you’ve got the means, this might be a welcome addition to the backyard! The build was posted on Reddit, the users of which had some helpful suggestions for improving the pool if you want to tackle this yourself. If you don’t have a solar thermal water heater, you could always make one of those too.
An interesting take on Hackerspace outreach is spooking the local community into calling the FAA and even the Air Force. It wasn’t exactly the plan at Quelab, but after an experimental solar tetroon got away from [Gonner Menning], one of the space’s members, that’s exactly what happened.
This is the first we remember hearing of solar tetroons. A tetroon is actually a fairly common weather balloon design using four triangle-shaped pieces. The solar part is pretty neat, it’s a balloon that uses the sun to heat air inside of a balloon. Instead of filling the bladder with a lighter-than-air gas it is filled with regular air and the sun’s rays heat it to become lighter than the surrounding ambient air.
For this particular flight the balloon was never supposed to be off the tether. Previous iterations had turned out to be rather poor fliers. Of course it figures that when [Gonner] finally tuned the design with an optimal weight to lift ratio it slipped its leash and got away. The GPS package tracked it for quite a while but ended up dying and the craft was nary to be found.
We weren’t going to embed the local news coverage video, but at the end the talking heads end up rolling around the word “Hackerspace” in their mouths like it’s foreign food. Good for a giggle after the break.
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