Self-Cleaning Tech Could Help Solar Panels Keep Efficiency Up

Solar panels are a special kind of magic — turning light into useful electrical energy. However, they don’t work nearly as well when they’re covered in dust, dirt, and grime. Conventional solutions involve spraying panels down with pure water, which is expensive and wasteful, or dry scrubbing, which can cause efficiency loss through scratching the panels. However, innovative new methods may offer useful solutions in this area, as shared by EETimes.

Researchers at MIT have explored the use of electrostatic methods to remove dust from solar panels. By creating a sufficiently strong electrostatic field, dust particles can be compelled to leap off of solar panels. The cleaning method requires no water and is entirely non-contact. It uses a motor system to pass a charged electrode past the surface of the panels, with the opposite charge applied to the panels themselves. This repels the dust from the panels and onto the moving electrode.

Other methods include the use of special “self-cleaning” glass manufactured with a laser etching technique. The method, referred to as Direct Laser Interference Patterning, or DLIP, creates microscopic features on the order of 300 nm to 30 um on the surface of the glass. The pattern creates a so-called “functional surface” from which dirt simply slides off. The laser-etched pattern has no negative impact on transparency.

If these ideas prove practical, expect them to take off quickly. Commercially viable technologies spread fast in the renewable space, as we’ve seen with the rapid uptake of floating solar farms in recent years. 

Solar Powered Split Wireless Mechanical Keyboard

When thinking about a perfect keyboard, some of us have a veritable laundry list: split, hot-swapping, wireless, 3d printed, encoders, and a custom layout. The Aloidia keyboard by [Nguyen Vincent] has all that and more.

One of the first things to notice is a row of solar panels on the top, which trickle charge the keyboard. The keyboard uses 65uA in idle and 30uA when in a deep sleep. With the solar panels providing anywhere between 600-1200uAh a day, the battery should last a year and a half under even harsh conditions. The encoders were specially chosen to reduce pull-up power consumption. Given the focus on power and the lack of wires between the halves, you might wonder how the connection to the computer is handled. Does one-half handle the connection and use more power? The answer is that both talk to a dongle based around an nRF52840. This lets the keyboard halves idle most of the time and enables the dongle to handle the expensive communications to the host PC.

Instead of an e-paper screen in the top left, [Nguyen] placed a Sharp memory display. The 3D-printed case is stunning, with no visible screws on the top and tenting feet on the bottom. The two halves snap together very satisfactorily with the power of magnets (the printed palm rests also magnetically attach). Overall it is an incredibly well-thought-out keyboard with all sorts of bells and whistles.

There are project logs with detail to dig into and more videos and photos. We love a good keyboard journey like this one that went for a more ergonomic shape that meant more custom wiring.

Schematics are up on hackaday.io in the files section—video after the break.

Thanks [Shantanu] for the tip!

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Supercon 2022: Irak Mayer Builds Self-Sustainable Outdoor IoT Devices

[Irak Mayer] has been exploring IoT applications for use with remote monitoring of irrigation control systems. As you would expect, the biggest challenges for moving data from the middle of a field to the home or office are with connectivity and power. Obviously, the further away from urbanization you get, the sparser both these aspects become, and the greater the challenge.

[Irak] solves his connectivity problem by assuming there is some WiFi network within range, building a system around the Blues Wireless WiFi note card. Substituting their cellular card would be an option for applications out of WiFi range, but presumably without changing too much on the system and software side of things. Leveraging the Adafruit FeatherWing INA219, which is a bidirectional current sensor with an I2C interface, for both the power generation and system consumption measurements. For control, [Irak] is using an Adafruit ESP32 board, but says little more about the hardware. On the software side, [Irak] is using the Blues Wireless NoteHub for the initial connection, which then routes the collected data onto the Adafruit IoT platform for collation purposes. The final part of the hardware is a LiPo battery which is on standby to soak up any excess power available from the energy harvesting. This is monitored by an LC709203f battery fuel gauge.

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Screenshot from the presentation, showing the datalogger product image next to the datalogger specs stated. The specs are suspiciously similar to those of a Raspberry Pi 3.

Reclaiming A Pi-Based Solar Datalogger

There’s quite a few devices on the market that contain a Raspberry Pi as their core, and after becoming a proud owner of a solar roof, [Paolo Bonzini] has found himself with an Entrade ENR-DTLA04DN datalogger which – let’s just say, it had some of the signs, and at FOSDEM 2023, he told us all about it. Installed under the promise of local-only logging, the datalogger gave away its nature with a Raspberry Pi logo-emblazoned power brick, a spec sheet identical to that of a Pi 3, and a MAC address belonging to the Raspberry Pi Foundation. That spec sheet also mentioned a MicroSD card – which eventually died, prompting [Paolo] to take the cover off. He dumped the faulty SD card, then replaced it – and put his own SSH keys on the device while at it.

At this point, Entrade no longer offered devices with local logging, only the option of cloud logging – free, but only for five years, clearly not an option if you like your home cloud-free; the local logging was not flawless either, and thus, the device was worth exploring. A quick peek at the filesystem netted him two large statically-compiled binaries, and strace gave him a way to snoop on RS485 communications between the datalogger and the solar roof-paired inverter. Next, he dug into the binaries, collecting information on how this device did its work. Previously, he found that the device provided an undocumented API over HTTP while connected to his network, and comparing the API’s workings to the data inside the binary netted him some good results – but not enough.

The main binary was identified to be Go code, and [Paolo] shows us a walkthrough on how to reverse-engineer such binaries in radare2, with a small collection of tricks to boot – for instance, grepping the output of strings for GitHub URLs in order to find out the libraries being used. In the end, having reverse-engineered the protocol, he fully rewrote the software, without the annoying bugs of the previous one, and integrated it into his home MQTT network powered by HomeAssistant. As a bonus, he also shows us the datalogger’s main PCB, which turned out to be a peculiar creation – not to spoil the surprise!

We imagine this research isn’t just useful for when you face a similar datalogger’s death, but is also quite handy for those who find themselves at the mercy of the pseudo-free cloud logging plan and would like to opt out. Solar tech seems to be an area where Raspberry Pi boards and proprietary interfaces aren’t uncommon, which is why we see hackers reverse-engineer solar power-related devices – for instance, check out this exploration of a solar inverter’s proprietary protocol to get data out of it, or reverse-engineering an end-of-life decommissioned but perfectly healthy solar inverter’s software to get the service menu password.

A Solar Supercap Power Supply To Keep Your Projects Running

Solar garden lights and many other similar trinkets typically rely on cheap rechargeable batteries as a power source when the sun isn’t shining. [Darryl] figured that a supercapacitor could do the job instead, and set about building a solar supercap power supply that could run various projects. 

The power supply is built to use a small 60 x 40mm solar panel that provides approximately 500 mW at max output. This charges two supercapacitors which feed their output into a TPS61200 boost converter, specifically designed for working with ultra-low input voltages down to 0.3 V. The boost convert can then be configured to output 3.3 V or 5 V depending on the desired voltage for the device to be powered. A special MOSFET array part is used to charge the dual supercaps in series, ensuring they stay balanced and don’t get overcharged by the sun.

The design has worked well in practice. [Darryl] reports that it has successfully powered a LoRa device reporting every 10 minutes for over two years without issue.

Solar power is a magical thing, capable of providing energy for free if you can get out there and capture it. If you’re working on your own solar-powered projects, don’t hesitate to drop us a line!

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Hackaday Links: September 11, 2022

Good news out of Mars from the little lunchbox that could — in the seven times that MOXIE has run since it arrived in February 2021, it has reached its target production of six grams of oxygen per hour, which is in line with the output of a modest tree here on Earth. The research team which includes MOXIE engineers report that although the solid oxide electrolysis machine has shown it can produce oxygen at almost any time or day of the Martian scale, they have not shown what MOXIE can do at dawn or dusk, when the temperature changes are substantial, but they say they have ‘an ace up (their) sleeve’ that will let them do that. We can’t wait to see what they mean.

In other, somewhat funnier space news — early last Sunday morning, the ESA’s Solar Orbiter was cruising by Venus as part of a gravity-assist maneuver to get the Orbiter closer to the Sun. Two days before the Orbiter was to reach its closest point to the spacious star, it spat a coronal mass ejection in the general direction of both Venus and the Orbiter (dibs on that band name), as if to say ‘boo’. Fortunately, the spacecraft is designed to withstand such slights, but the same cannot be said for Venus — these events have their way with Venus’ atmosphere, depleting it of gasses.

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Hackaday Prize 2022: A Sun-Chasing Robot

There’s plenty of power to be had from the sun, but you need to be out of the shade to receive it. [Dennis] built a robot by the name of Sun Chaser that has the smarts to go where the sun is shining.

Sun Chaser is essentially a robotic solar panel, tasked with filling up its batteries as much as possible. It can then be used as a power supply for campsites or other remote areas, and used to charge devices as required.

A Raspberry Pi runs the show, paired with a Squid motor controller to run the drive system. Sun Chaser has a motorized solar panel onboard which can track the sun for maximum output, with the aid of six photoresistors to guide the positioning. A camera is used to image the area around Sun Chaser, too, and processing is used to identify sunny regions which will provide the most energy.

Even outside of its useful applications, the idea of having a robot that can run around and keep itself juiced up is a fun one. Solar power gives a robot a greater sense of autonomy, after all. This author has experimented in this field to great enjoyment, too. Video after the break.

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