Clean Up Your Resin-Printing Rinse With Dialysis

September 5, 2023 by Dan Maloney 64 Comments

There’s a lot to like about resin 3D printing. The detail, the smooth surface finish, the mechanical simplicity of the printer itself compared to an FDM printer. But there are downsides, too, not least of which is the toxic waste that resin printing generates. What’s one to do with all that resin-tainted alcohol left over from curing prints?

How about sending it through this homebrew filtering apparatus to make it ready for reuse? [Involute] likens this process to dialysis, and while we see the similarities, what’s going on here is a lot simpler than the process used to filter wastes from the blood in patients with failing kidneys — there are no semipermeable membranes used here. Not that the idea suffers from its simplicity, mind you; it just removes unpolymerized resin from the isopropyl alcohol rinse using the same photopolymerization process used during printing. Continue reading “Clean Up Your Resin-Printing Rinse With Dialysis” →

2023 Hackaday Prize: Two Bee Or More Bee Swarm Detection

August 21, 2023 by Matthew Carlson 6 Comments

In the bustling world of bees, swarming is the ultimate game of real estate shuffle. When a hive gets too crowded or craves a change of scenery, colonies scout out swarms for a new hive. [Captain Flatus O’Flaherty] is a beekeeper trying to capture more native honey bees, and a custom LoRa-enabled capture hive helps him do that.

A catch hive, perched high and mighty, lures scouting as potential new homes. If selected, a swarm of over a thousand bees can move in, where [Flatus]’s detector comes in. Many catch hives are scattered around, and manually checking them is difficult. While the breath of one bee is hard to see, a thousand bees produce enough CO2 to be detected by a sensor. A custom PCB with a solar-powered +30dB LoRa radio measures CO2 and reports back. The PCB contains an ESP32 D4 and a 1-watt Ebyte E22-400M30S LoRa module. If the CO2 levels are still elevated at nightfall, [Flatus] can be pretty confident a swarm has moved in.

Using the data collected, he massaged it to create a dataset suitable for training on XGBoost. With weather data and other conditions, the model tries to predict when a swarm is more or less likely to happen. Apis Mellifera (the local honeybee around [Flatus]) loves sun-kissed, warm, humid afternoons with little wind.

We’ve seen beehive monitors before and love exploring what the data could be used for—video after the break.

Continue reading “2023 Hackaday Prize: Two Bee Or More Bee Swarm Detection” →

the PCB without the case on, showing the screen, battery, and removable sensor

2023 Hackaday Prize: A Reusable Plant Monitor

August 20, 2023 by Matthew Carlson 6 Comments

[Ovidiu] cares for their house plants, trying to dial in the perfect soil humidity and light levels. However, many cheap monitors tend to rust after a few weeks of sitting in a damp, slightly acidic environment. By creating a custom plant monitor with a removable probe, not only can [Ovidiu] integrate better with their Home Assistant setup, but it will also be less wasteful.

The build starts with an ESP32-S3, a TP4056 charging circuit, a small e-ink display, and an AHT20 IC for air humidity and temperature. The ESP32 reads the probe using the capacitance measuring devices for touchpads built into the chip. Or course, a 450mAh battery provides a battery life of about 11 days. The probe is just a bare PCB with a connector at the top, making them cheap and easy to swap. They included pads on the probe for a thermistor for reading soil temperature, but this is optional. A handsome 3D-printed case wraps it all up nicely.

Continue reading “2023 Hackaday Prize: A Reusable Plant Monitor” →

A series of trapezoidal steel "buckets" attached together to form a metal water wheel. They are arranged around a square center frame that attaches to a hub for the wheel to spin about. The wheel is next to a stream and four people of various ages appear to be talking around it. A cinder block building with a metal roof is in the left background, and an older, yellow stone building is far off in the distance on the right of the image. The landscape is lush, green, and mountainous.

Open Source Waterwheel

August 20, 2023 by Navarre Bartz 28 Comments

Here in the West, power going out is an unusual event. But in more remote regions like the Himalayas, reliable electricity isn’t a given. A group of local craftspeople, researchers, and operators in Nepal have worked together to devise a modular waterwheel system.

Based on a 20-30 cm-wide bucket module consisting of only four galvanized steel components, the wheels can be easily built and deployed using resources and tools that are easy to find anywhere in the world. Current test devices generate between 120 and 1,400 Watts of power, depending on the device’s size.

A software tool was also developed that takes the head and flow rate of a location as inputs to calculate the dimensions of the optimal wheel and expected power output for an installation. This lets communities find ideal sites for power generation and calculate the expected costs.

We’ve covered a few other DIY hydropower setups, from repurposed washing machines to custom scratch builds.

Off-Grid EV Charging

August 19, 2023 by Bryan Cockfield 40 Comments

There are plenty of reasons to install solar panels on one’s home. Reducing electric bills, reducing carbon footprint, or simply being in a location without electric service are all fairly common. While some of those might be true for [Dominic], he had another motivating factor. He wanted to install a charger for his electric vehicles but upgrading the electric service at his house would have been prohibitively expensive. So rather than dig up a bunch of his neighbors’ gardens to run a new service wire in he built this off-grid setup instead.

Hooking up solar panels to a battery and charge controller is usually not too hard, but getting enough energy to charge an EV out of a system all at once is more challenging. The system is based on several 550W solar modules which all charge a lithium iron phosphate battery. The battery can output 100 A DC at 48 V which gives more than enough power to charge an EV. However there were some problems getting this much power through an inverter. His first choice let out the magic smoke when it was connected, and it wasn’t until he settled on a Growatt inverter capable of outputting 3.5 kW that the system really started to take shape.

All of this is fairly straightforward, but there’s an extra touch here that makes this project noteworthy. [Dominic] wanted to balance incoming power from the photovoltaic system to the current demands from the EVs to put less strain on the battery. An ESP32 was programmed to only send as much power to the EVs as the solar system is producing at any given time, and also includes some extra logic to make sure the battery doesn’t drain itself from the idle power requirements of the inverter. Right now the system works well but the true test will be when it goes through its first winter. Even though solar panels are more efficient at colder temperatures, if the amount of sunlight or the angle of the panels aren’t ideal there is generally much less production.

Black Graphics On Your TV, For A Greener World?

August 14, 2023 by Jenny List 97 Comments

Can you really save energy by carefully choosing the colors displayed on a TV screen? Under some conditions, yes. Or at least that’s the conclusion of a team at the BBC that looked at reducing the energy consumption impact of their output by using what they call Lower Carbon Graphics. In short, they’re trying to ensure that OLED displays or those with reactive backlights use less energy when displaying BBC graphics, simply by using more black.

It turns out that a lot of British households play radio stations on their TVs, and the BBC sends a static image to each screen in this mode. As part of a redesign across the organisation, the BBC removed the bright background colours from these images and replaced it with black, with a remarkable reduction in power consumption, at least on OLED and FALD screens. (On normally backlit screens, 89% of British TVs, this does nothing.)

If you look hard at their numbers, though, listening to radio on the TV is horrendously inefficient; can you imagine a radio that consumes 100 W? If the BBC really wants to help reduce media-related energy consumption, maybe they should stop broadcasting radio programming on the TV entirely.

Anyway, as we move toward a larger fraction of OLED screens, on TVs and monitors alike, it’s fun to think that darker images use up to 40% less power. Who knew that Hackaday was so environmentally friendly? Black is the new green!

Header: RIA Novosti archive/ Igor Vinogradov, CC-BY-SA 3.0.

3D Print Your Own Seiko-Style “Magic Lever” Energy Harvester

August 9, 2023 by Donald Papp 20 Comments

Back in 1956, Seiko created their “magic lever” as an integral part of self-winding mechanical watches, which were essentially mechanical energy harvesters. The magic lever is a type of ratcheting arrangement that ensures a main gear only ever advances in a single direction. [Robert Murray-Smith] goes into detail in this video (here’s a link cued up to 1:50 where he begins discussing the magic lever)

There is a lot of naturally-occuring reciprocal motion in our natural world. That is to say, there is plenty of back-and-forth and side-to-side, but not a lot of round-and-round. So, an effective mechanism for a self-winding watch needed a way to convert unpredictable reciprocal motion into a unidirectional rotary one. The magic lever was one way to do so, and it only has three main parts. [Robert] drew these up into 3D models, which he demonstrates in his video, embedded below.

The 3D models for Seiko’s magic lever are available here, and while it’s fun to play with, [Robert] wonders if it could be integrated into something else. We’ve certainly seen plenty of energy harvesting projects, and while they are mostly electrical, we’ve also seen ideas about how to harvest the energy from falling raindrops.

Continue reading “3D Print Your Own Seiko-Style “Magic Lever” Energy Harvester” →