A Single-Watt Hydroponic Lighting System

October 31, 2022 by Bryan Cockfield 24 Comments

Hydroponic systems are an increasingly popular way to grow plants indoors using a minimum of resources. Even some commercial farming operations are coming online using hydroponic growing techniques, as these methods consume much less water, land area, and other resources than traditional agricultural methods. The downside is that the required lighting systems often take an incredible amount of energy. That’s why [ColdDayApril] set up a challenge to grow a plant hydroponically using no more than a single watt.

The system is set up to grow a single pepper plant in what is known as a deep-water culture, where the plant is suspended in a nutrient solution which has everything it needs to grow. The lightning system is based around the Samsung LM301B which comes close to the physical limits for converting electricity into white light and can manage around 220 lumens. A special power supply is needed for these low-power diodes, and the light is efficiently directed towards the plant using a purpose-built reflective housing. By placing this assembly very close to the plant and adjusting it as it grows, [ColdDayApril] was able to take the pepper plant from seed to flowering in 92 days.

It’s worth noting that the rest of the system uses a little bit of energy too. A two watt fan helps circulate some air in the hydroponic enclosure, and deep-water systems usually require an air pump to oxygenate the water which uses another two watts. This is still an impressive accomplishment as most hobbyist builds use lighting systems rated in the hundreds of watts and use orders of magnitude more energy. But, if you’re willing to add some fish into the system you can mitigate some of the energy requirements needed for managing the water system even further.

A Solar Supercap Power Supply To Keep Your Projects Running

October 27, 2022 by Lewin Day 16 Comments

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!

ERRF 22: Recreator 3D Turns Trash Into Filament

October 21, 2022 by Tom Nardi 30 Comments

In Back to the Future, Doc Brown returns to 1985 with a version of his DeLorean time machine that has been modified with technology from the future. After telling Marty they need to go on yet another adventure, Doc recharges the DeLorean’s flux capacitor and time circuits by tossing pieces of garbage into the slick Mr. Fusion unit mounted to the rear of the vehicle. The joke being that, in the future, you could simply head over to the local big box store and pick up a kitchen appliance that’s capable of converting waste matter into energy.

Unfortunately, we’re nowhere near powering our homes with banana peels and beer cans. But if the Recreator 3D is any indication, the technology required to turn plastic bottles rescued from the trash into viable PET filament for your 3D printer is all but upon us. While there are still some aspects of the process that could stand to be streamlined, such as fusing multiple runs of filament together into one continuous roll, the core concepts all seem to be in place.

The MK5Kit Mini is currently in development with LDO Motors.

Creator [Josh Taylor] made the trip out to the 2022 East Coast RepRap Festival to not only show off the Recreator 3D, a project he’s been working on now for over a year, but to get people excited about the idea of turning waste plastic into filament. It’s not necessarily a new concept, and in fact [Josh] says earlier efforts such as the PETBOT are what inspired him to create his own open source take on the “pultrusion” concept.

According to [Josh], actually printing with the recycled filament isn’t that different from using commercial PETG, though it’s recommended you lower your speeds. A nozzle temperature of around 260 °C seems to work best, with the bed at 70 °C. Interestingly, the filament produced by the process is actually hollow inside, so the most critical change to make is increasing your extrusion rate to about 130% of normal to compensate for the internal void.

The current revision of the Recreator 3D, known as the MK5Kit, can be assembled using several core components salvaged from a low-cost Ender 3 printer in addition to a number of parts that the user will need to print themselves. For those who’d rather not source the parts, [Josh] says he hopes to get formal kits put together sometime next year, thanks to a partnership with LDO Motors.

But ultimately, [Josh] says the most important thing to him is that the plastic is recycled instead of getting sent to a landfill or incinerator. So whether you build a Recreator 3D or come up with your own design, all are welcome to the PET Pultruders United Facebook group he’s created to discuss the finer points of turning plastic trash into treasure.

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A solar inverter that asks for a password on its display

Decompiling Software To Fix An Old Solar Inverter

October 20, 2022 by Robin Kearey 16 Comments

It’s a fact of life that electronic devices become obsolete after a few years. Sometimes this is because technology has moved on, but it can also happen that a perfectly functional device becomes near-useless simply because the original manufacturer no longer supports it. When [Buy It Fix It] found a pair of second-hand Power-One Aurora solar inverters, he ran into an issue for which he needed access to the service menu, which happened to be password-protected. The original manufacturer had ceased to exist, and the current owner of the brand name was unable to help, so [Buy It Fix It] had to resort to reverse engineering to find the password.

Thanks to the Wayback Machine over at the Internet Archive, [Buy It Fix It] was able to download the PC software bundle that originally came with the inverters. But in order to access all features, a password was required that could only be obtained by registering the unit with the manufacturer. That wasn’t going to happen, so [Buy It Fix It] fired up dnSpy, a decompiler and debugger for .NET programs. After a bit of searching he found the section that checked the password, and by simply copying that section into a new program he was able to make his own key generator.

With the service password now available, [Buy It Fix It] was able to set the inverter to the correct voltage setting and hook it up to his solar panels. Interestingly, the program code also had references to “PONG”, “Tetris” and “tiramisu” at various places; these turned out to be Easter eggs in the code, containing simple versions of those two games as well as a photo of the Italian dessert.

Inside the software archive was also another program that enabled the programming of low-level functions within the inverter, things that few users would ever need to touch. This program was not written in .NET but in C or something similar, so it required the use of x32dbg to look at the machine code. Again, this program was password-protected, but the master password was simply stored as the unencrypted string “91951” — the last five digits of the manufacturer’s old phone number.

The inverter was not actually working when [Buy It Fix It] first got it, and his repair video (also embedded below) is also well worth watching if you’re into power electronics repair. Hacking solar inverters to enable more features is often possible, but of course it’s much easier if the entire design is open source.

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An infographic showing a tap with a sensor and a flow meter display

2022 Hackaday Prize: Sensible Flow Helps You Keep Track Of Your Water Usage

October 17, 2022 by Robin Kearey 15 Comments

Safe, clean drinking water is a scarce resource that shouldn’t be wasted. But it’s not always easy to see how much you’re using when you turn on the tap: is it one liter a minute? Is it ten? How much do you actually use when washing your hands or brushing your teeth? If you’d like to get some hard data on your water usage, have a look at [Josh EJ]’s Sensible Flow project. It contains designs for a set of sensors that measure your water consumption and a convenient little display that shows the total amount consumed.

The most obvious way of measuring water consumption is to install an off-the-shelf flow meter onto your pipe, which is something that Sensible Flow supports. But probably the most interesting part of the project is a design for a non-invasive flow sensor that you can simply attach to any type of tap. This sensor contains a nine-axis inertial measurement unit (IMU) that detects how far you’ve twisted, turned or tilted the handle, and uses that information to estimate the amount of water flow. You will need to perform an initial calibration step using a timer and measuring cup, but you won’t have to rip open your plumbing just to keep track of your water usage.

Both types of sensors are powered by a coin cell battery that is estimated to work for about one year, thanks to a power-efficient Arduino Pro Mini and a BlueTooth Low Energy (BLE) module to communicate with the base station. The base station plugs into a wall socket and shows the total water consumption on a small one-inch OLED display. STL files for the enclosures are available on the project page, along with detailed circuit diagrams that show how all the parts are connected.

We’ve seen several water flow measurement systems for home use, such as this neat ESP8266-based shower water monitor. If you prefer just a simple visual reminder to turn off the tap, have a look at this LED gadget.

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A Simple Stove, Built For Beans

October 14, 2022 by Bryan Cockfield 17 Comments

Sitting around a campfire or fireplace is an aesthetically pleasing experience in most situations, and can even provide some warmth. But unless you have a modern wood-burning appliance, it’s likely that most of the energy available in the biomass is escaping as un-burned vapors. Surprisingly, solving this problem is almost as easy as buying a can of beans at the store, and the result is a very efficient stove which can be used for heat in a pinch.

[Robert] is demonstrating this gasifier stove, not with beans but using both a can of peas and a larger can of potatoes. Various holes are drilled in each can in a specific pattern, and then the smaller pea can is fitted inside the larger potato can. Once a fire is going, the holes allow for air to flow in a way which traps the escaping un-burned vapors from the fuel and burns them as they flow through the contraption. No moving parts are required; this is all powered by the natural airflow that’s produced by the heat of the fire.

The result of a build like this is not only a stove which can extract a much higher percentage of the available fuel, but also quires much less fuel for a given amount of heat, and produces a much cleaner, less smokey fire. [Robert] also added a screen mantle which allows for this to be used more as a heat source, but similar builds can also be used just as effectively for cooking, too.

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Hackaday Prize 2022: Hedge Watcher Aims To Save Precious Bird Life

October 13, 2022 by Lewin Day 12 Comments

Hedges aren’t just a pretty garden decoration. They’re also a major habitat for many species of insects, birds, and other wildlife. In some areas, a lot of hedge trimming goes during the time that local birds are raising their fledglings, which causes harm at a crucial time. Thus, [Johann Elias Stoetzer] and fellow students were inspired to create Hedge Watcher.

Birds can easily blend in with their surroundings, but thermal cameras are a great way to spot them.

The concept is simple – using thermal vision to spot birds inside a hedge when they may not otherwise be easily visible. Many species blend in with their surroundings in a visual manner, so thermal imaging is a great way to get around this. It can help to avoid destroying nests or otherwise harming birds when trimming back hedges. The idea was sourced from large-scale agricultural operations, which regularly use thermal cameras mounted on drones to look for wildlife before harvesting a field.

However, staring at a thermal camera readout every few seconds while trimming hedges isn’t exactly practical. Instead, the students created an augmented reality (AR) monocular to allow the user to trim hedges at the same time as keeping an eye on the thermal camera feed. Further work involved testing a binocular AR headset, as well as a VR headset. The AR setups proved most useful as they allowed for better situational awareness while working.

It’s a creative solution to protecting the local birdlife, and is to be applauded. There’s plenty of hubris around potential uses for augmented reality, but this is a great example of a real and practical one. And, if you’re keen to experiment with AR yourself, note that it doesn’t have to break the bank either!