Open-Source Solar Modules

February 5, 2024 by Bryan Cockfield 13 Comments

As the price of solar panels continues to fall, more and more places find it economical to build solar farms that might not have been able to at higher prices. High latitude locations, places with more clouds than sun, and other challenging build sites all are seeing increased green energy development. The modules being used have one main downside, though, which is that they’re essentially a black box encased in resin and plastic, so if one of the small cells fails a large percentage of the panel may be rendered useless with no way to repair it. A solar development kit like this one from a group called Biosphere Solar is looking to create repairable, DIY modules that are completely open source, to help solve this issue.

The modular solar panel is made from a 3D printed holster which can hold a number of individual solar cells. With the cells placed in the layout and soldered together, they are then sandwiched between a few layers of a clear material like acrylic or glass with a seal around the exterior to prevent water intrusion. Since the project is open-source any number of materials can be used for the solar cell casing, and with the STL file available it’s not strictly necessary to 3D print the case as other manufacturing methods could be used. The only thing left is to hook up a DC/DC converter if you need one, and perhaps also a number of bypass and/or blocking diodes depending on your panel’s electrical layout.

The project is still in active development, and some more information can be found at the project’s website. While the “recyclability” of large-scale solar farms is indeed a problem, it’s arguably one which has been overblown by various interests who are trying to cast doubt on green energy. A small build like this won’t solve either problem anytime soon, so the real utility here would be for home users with small off-grid needs who want an open-source, repairable panel. It’s a great method to make sure solar technology is accessible and repairable for anyone that wants it, and in a way this approach to building hardware reminds us a lot of the Framework laptops.

Wireless Data Connections Through Light

August 25, 2023 by Bryan Cockfield 38 Comments

When wired networking or data connections can’t be made, for reasons of distance or practicality, various wireless protocols are available to us. Wi-Fi is among the most common, at least as far as networking personal computers is concerned, but other methods such as LoRa or Zigbee are available when data rates are low and distances great. All of these methods share one thing in common, though: their use of radio waves to send data. Using other parts of the electromagnetic spectrum is not out of the question, though, and [mircemk] demonstrates using light as the medium instead of radio.

Although this isn’t a new technology (“Li-Fi” was first introduced in 2011) it’s not one that we see often. It does have a few benefits though, including high rates of data transmission. In this system, [mircemk] is using an LED to send the information and a solar cell as the receiver. The LED is connected to a simple analog modulator circuit, which takes an audio signal as its input and sends the data to the light. The solar cell sends its data, with the help of a capacitor, straight to the aux input on a radio which is used to convert the signal back to audio.

Some of the other perks of a system like this are seen here as well. The audio is clear even as the light source and solar cell are separated at a fairly significant distance, perhaps ten meters or so. This might not seem like a lot compared to Wi-Fi, but another perk shown is that this method can be used within existing lighting systems since the modulation is not detectable by the human eye. Outside of a home or office setting, systems like these can also be used to send data much greater distances as well, as long as the LED is replaced with a laser.

Continue reading “Wireless Data Connections Through Light” →

Two nearly-identical black and white images of a solar installation on top of a roof in NYC. The left image purports to be from 1909 while the other says it is from 1884. Both show the same ornate building architecture in the background and angle of the panels.

The Mysterious Case Of The Disappearing Inventor

August 19, 2023 by Navarre Bartz 10 Comments

When combing through the history of technological innovation, we often find that pinning down a given inventor of something can be tricky. [Foeke Postma] at Bellingcat shows us that even the Smithsonian can get it wrong when given faulty information.

The mystery in question is the disappearance of inventor [George Cove] from a photograph of his solar panel system from 1909 and its reuse as evidence of the first photovoltaic solar panel by another inventor, [Charles Fritts], around 1884. Questions first arose about this image in 2021, but whether this was an example of photo manipulation was merely speculation at the time.

Continue reading “The Mysterious Case Of The Disappearing Inventor” →

An E-ink display showing Conway's Game of Life, with a solar cell beneath it

Solar Powered Game Of Life Follows The Sun’s Rhythm

July 28, 2023 by Robin Kearey 5 Comments

Conway’s Game of Life is a beautiful example of how complex behavior can emerge from a few very simple rules. But while it uses biological terminology such as “cells”, “alive” and “generation”, the basic game is too simplistic to be a model for any real-world biological process. It’s easy to add features to make it a bit more life-like, however, as [David Hamp-Gonsalves] has done by giving the Conway’s creation something of a circadian rhythm.

The basic idea is that the speed at which [David]’s Game of Life evolves is governed by the amount of ambient light. The game runs off a solar cell that charges a battery, with the battery’s voltage determining how long it takes to advance the game by one generation. The system is therefore highly active in full sunlight, and grinds almost to a complete halt at night.

An ESP32 runs the simulation and outputs the result to a 400 x 300 pixel e-ink display. The display is extremely power-efficient by its very nature; the ESP’s main processor core, on the other hand, is deliberately placed into deep sleep mode most of the time to save as much power as possible. The Ultra Low Power (ULP) co-processor, meanwhile, keeps an eye on the lithium battery’s voltage as it’s slowly being charged by the solar cell. When the voltage reaches 3.3 V, the main CPU wakes up and computes the Game’s new state. In bright sunlight this happens every few seconds, while on an overcast day it could take minutes or even hours.

[David]’s interesting idea of changing Life‘s activity based on the amount of energy available turns the Game into something resembling a cold-blooded animal. We’ve seen a similar approach in a “solar creature” that runs a Life-life simulation on a seven-segment LCD. If it’s speed you care about however, you’re better off implementing Life in an FPGA.

A loudspeaker with a supercapacitor PCB next to it

Hackaday Prize 2023: Supercapacitors Let Solar Speaker Work In Darkness

July 8, 2023 by Robin Kearey 13 Comments

Solar panels are a great way to generate clean electricity, but require some energy storage mechanism if you also want to use their power at night. This can be a bit tricky for large solar farms that feed into the grid, which require enormous battery banks or pumped storage systems to capture a reasonable amount of energy. It’s much easier for small, handheld solar gadgets, which work just fine with a small rechargeable battery or even a big capacitor. [Jamie Matthews], for instance, built a loudspeaker that runs on solar power but can also work in the dark thanks to two supercapacitors.

The speaker’s 3D-printed case has a 60 x 90 mm² solar panel mounted at the front, which charges a pair of 400 Farad supercaps. Audio input is either through a classic 3.5 mm socket or through the analog audio feature of a USB-C socket. That same USB port can also be used to directly charge the supercaps when no sunlight is available, or to attach a Bluetooth audio receiver, which in that case will be powered by the speaker.

A speaker's passive radiator next to a solar panel — The solar panel sits right next to the passive radiator before both are covered with speaker fabric.

The speaker’s outer shell, the front bezel, and even the passive radiator are 3D-printed and spray-painted. The radiator is made of a center cap that is weighed down by a couple of M4 screws and suspended in a flexible membrane. [Jamie] used glue on all openings to ensure the box remains nearly airtight, which is required for the passive radiator to work properly. Speaker fabric is used to cover the front, including the solar panel – it’s apparently transparent enough to let a few watts of solar power through.

A salvaged three-inch Bose driver is the actual audio source. It’s driven by a TI TPA2013D1 chip, which is a 2.7 W class-D amplifier with an integrated boost converter. This enables the chip to keep a constant output power level across a wide supply voltage range – ideal for supercapacitor operation since supercaps don’t keep a constant voltage like lithium batteries do.

[Jamie] has used the speaker for more than nine months so far and has only had to charge it twice manually. It probably helps that he lives in sunny South Africa, but we’ve seen similar solar audio projects work just fine in places like Denmark. If you’re taking your boombox to the beach, a sunscreen reminder feature might also come in handy.

If You Can’t See A Solar Panel, That Doesn’t Mean It’s Not There

December 31, 2022 by Jenny List 45 Comments

In the shift away from fossil fuel energy sources, there has been a huge expansion in solar power. We’ve seen solar thermal plants in the desert and photovoltaic panel farms covering huge areas of land, but perhaps the most potential comes from placing the panels on rooftops. In some parts of the world this is encouraged through a system of subsidies, as is the case in Italy. But what if your building is part of a protected world heritage site such as the Roman city of Pompeii? The answer comes in the form of traditional roof tiles that hide their photovoltaic elements under a polymer skin that looks for all the world like a traditional Roman pan tile. As is so often the case with such products, the manufacturer’s description page is cagey about the details in the name of protecting their invention. What they do tell us is that the tile uses conventional solar cells mounted underneath the polymer layer, which is described as “opaque at the sight but translucent to sun rays“. This sounds like an inherent contradiction, so naturally, we’re intrigued as to how it works. Continue reading “If You Can’t See A Solar Panel, That Doesn’t Mean It’s Not There” →

Solar Cells As Art Form

August 31, 2022 by Bryan Cockfield 10 Comments

When most of us approach a project, we have a certain problem to solve. 3D printing, microcontrollers, batteries, and all kinds of technologies are usually tools to accomplish some task. This is not necessarily true in the art world, though, where the intrinsic nature of these tools can be explored for their own sake rather than as a means to an end. The latest one that came across our desk is this light-powered sound generator.

The art piece looks a bit like a mobile with rotating arms, holding various small solar cells each connected to a speaker. As the arms pivot, the light falling on the cells changes which drives a specially-designed circuit connected to a speaker. The circuit acts as an oscillator, passing the changing voltage from the cell through various capacitors and transistors to produce changing tones in the speaker.

The effect of the rotating solar panels is not only oscillations from the speakers as the light changes, but oscillations in the sound of the speakers as they rotate towards and away from the observer. It’s a unique project and perfect for the art show it was in. It’s also not the only sound-focused art installation we’ve ever seen before, be sure to check out this one based on an ESP32.