Winter-Proof (And Improve) Your Resin 3D Printing

January 31, 2025 by Donald Papp 5 Comments

Was your 3D printer working fine over the summer, and now it’s not? With colder temperatures comes an overall surge in print failure reports — particularly with resin-based printers that might reside in outbuildings, basements, or garages. If you think this applies to you, don’t miss [Jan Mrázek]’s tips on improving cold-weather print results. His tips target the main reasons prints fail, helping to make the process a little more resilient overall. [Jan]’s advice is the product of long experience and experimentation, so don’t miss out.

With environmental changes comes the possibility that things change just enough to interfere with layers forming properly. The most beneficial thing overall is to maintain a consistent resin temperature; between 22 and 30 degrees Celsius is optimal. A resin heater is one solution, and there are many DIY options using simple parts. Some of the newer (and more expensive) printers have heaters built in, but most existing hobbyist machines do not.

Temperature control isn’t the only thing, either. Layer formation and build plate adhesion can all be improved by adding rest times between layers. Yes, this increases print time. It also allows resin to settle before the next layer, improving adhesion and preventing blooming (a rough texture caused by an imperfect cure.) Since resin flows less readily at lower temperatures, rest times can help improve results. The best setting depends heavily on your particular setup, so [Jan] gives tips on finding optimal rest times.

Most common knowledge and advice from well-meaning communities online focuses on increasing exposure time or blaming the build plate. [Jan] feels that these are ultimately the wrong way to go about addressing failures. Usually, an environmental change (like the arrival of winter) has simply pushed a printer that was not optimized in the first place outside of its narrow comfort zone. A little optimization can set things back on track, making the printer more resilient and reliable overall.

Electric Vehicle Charging Heats Up

January 22, 2025 by Bryan Cockfield 64 Comments

As the electric vehicle takeover slowly lumbers along, marginally increasing efficiencies for certain applications while entrenching car-centric urban design even further, there are some knock-on effects that are benefiting people and infrastructure beyond simple transportation. Vehicle-to-grid technology has applications for providing energy from the car back to the grid for things like power outages or grid leveling. But [Technology Connections] is taking this logic one step further. Since a large number of EV owners have charging stations built into their garages, he wondered if these charging stations could be used for other tasks and built an electric heater which can use one for power.

This project uses a level 2 charger, capable of delivering many kilowatts of power to an EV over fairly standard 240V home wiring with a smart controller in between that and the car. Compared to a level 1 charger which can only trickle charge a car on a standard 120V outlet (in the US) or a DC fast charger which can provide a truly tremendous amount of energy in a very short time, these are a happy middle ground. So, while it’s true a homeowner could simply wire up another 240V outlet for this type of space heater or other similar application, this project uses the existing infrastructure of the home to avoid redundancies like that.

Of course this isn’t exactly plug-and-play. Car chargers communicate with vehicles to negotiate power capabilities with each other, so any appliance wanting to use one as a bulk electric supply needs to be able to perform this negotiation. To get the full power available in this case all that’s needed is a resistor connected to one of the signal wires, but this won’t work for all cases and could overload smaller charging stations. For that a more complex signalling method is needed, but since this was more of a proof-of-concept we’ll still call it a success. For those wanting to DIY the charger itself, building one from the ground up is fairly straightforward as well.

Thanks to [Billy] for the tip!

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Hot Water Heater Hacked To Run On Solar Juice

September 6, 2024 by Lewin Day 41 Comments

It’s 2024, and there’s no getting around it. Grid energy is expensive. [Darrell] realized that a lot of his money was going on water heating, and he came up with a neat solution. What if he could hack in some solar power to slash his bills at a minimum of fuss? It worked so well for him, he’s whipped up a calculator to help others do the same.

[Darrell]’s idea was simple enough. He hooked up solar panels to just the bottom heating element of his hot water heater. This cut his power bill in half. His calculator is now up at pvh20.com, and it’s designed to help you figure out if it’s feasible for you. It takes into account your location, local power prices, and the amount of sun your area tends to get on a regular basis. It also takes into account the solar panels you intend to use and your water heater to determine how many panels you’ll need for properly hot water. Key all that in, and you’re well on your way to speccing a decent solar hot water setup. From there you’ll just need to buy the right stuff and wire it all up properly.

If you live in an area where the sun shines freely and the power is more expensive than printer ink, this could be a project well worth pursuing. Cheaper hot water is a grand thing, after all. [Darrell’s] calculator is really only the first step, and it doesn’t deal with the practicalities of installation, but that’s half the fun of a good project, right? Happy hacking!

Baseboard Heaters Get Automated

April 10, 2024 by Bryan Cockfield 12 Comments

If you’re lucky enough to have central heating and/or air conditioning, with an automatic thermostat, you probably don’t have to worry too much about the outside temperature. But central HVAC is far from the only way of maintaining temperature in a home. From wood stoves to boilers there are many options depending on your climate and home type, and [Murphy’s Law] has a decentralized baseboard system instead of something centralized. An ESP8266 solution was found that was able to tie them all together.

There are other types of baseboard heaters, but in [Murphy’s Law]’s case the heaters were electric with a separate thermostat for each heater. Rather than build a control system from the ground up to replace the thermostats, turnkey smart wall switches were used instead. These switches happened to be based on the popular ESP8266 microcontroller, like plenty of other off-the-shelf automation solutions, which meant less work needed to be done on the line voltage side and the microcontroller’s firmware could be easily customized for use with Home Assistant.

While [Murphy’s Law] doesn’t live in the home with the fleet of electric baseboard heaters anymore, the new home has a single baseboard heater to keep a bathroom warm since the central heating system doesn’t quite keep it warm enough. This system is able to scale up or down based on number of heaters, though, so it’s still a capable solution for the single room and has since been updated to use the ESP32. All of the code for this project is available on GitHub as well, and for those of you attempting to add other HVAC components to a home automation system this project that loops in a heat pump is worth taking a look at as well.

Rocket Stove Efficiently Heats Water

August 4, 2023 by Bryan Cockfield 19 Comments

Rocket stoves are an interesting, if often overlooked, method for cooking or for generating heat. Designed to use biomass that might otherwise be wasted, such as wood, twigs, or other agricultural byproducts, they are remarkably efficient and perform relatively complete combustion due to their design, meaning that there are fewer air quality issues caused when using these stoves than other methods. When integrated with a little bit of plumbing, they can also be used to provide a large amount of hot water to something like an off-grid home as well.

[Little Aussie Rockets] starts off the build by fabricating the feed point for the fuel out of steel, and attaching it to a chimney section. This is the fundamental part of a rocket stove, which sucks air in past the fuel, burns it, and exhausts it up the chimney. A few sections of pipe are welded into the chimney section to heat the water as it passes through, and then an enclosure is made for the stove to provide insulation and improve its efficiency. The rocket stove was able to effortlessly heat 80 liters of water to 70°C in a little over an hour using a few scraps of wood.

The metalworking skills of [Little Aussie Rockets] are also on full display here, which makes the video well worth watching on its own. Rocket stoves themselves can be remarkably simple for how well they work, and can even be built in miniature to take on camping trips as a lightweight alternative to needing to carry gas canisters, since they can use small twigs for fuel very easily. We’ve also seen much larger, more complex versions designed for cooking huge amounts of food.

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Home Heating With Bitcoin Miners Is Now A Real Thing

May 13, 2023 by Tom Nardi 63 Comments

If you were reading this post a month ago, you could have been forgiven for thinking it was an April Fools post. But we assure you, this is no joke. A company called HeatBit has recently opened preorders for their second generation of Bitcoin miner that doubles as a space heater.

The logic goes something like this: if you’re going to be using an electric space heater anyway, which essentially generates heat by wasting a bunch of energy with a resistive element, why not replace that element with a Bitcoin miner instead? Or at least, some of the element. The specs listed for the HeatBit Mini note that the miner itself only consumes 300 watts, which is only responsible for a fraction of the device’s total heat output. Most of the thermal work is actually done by a traditional 1000 watt heater built inside the 46 cm (18 inch) tall cylindrical device.

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Tube Amplifier Uses Low Voltage, Sips Battery

April 6, 2023 by Bryan Cockfield 25 Comments

Much like vinyl records, tube amplifiers are still prized for their perceived sound qualities, even though both technologies have been largely replaced otherwise. The major drawback to designing around vacuum tubes, if you can find them at all, is often driving them with the large voltages they often require to heat them to the proper temperatures. There are a small handful of old tubes that need an impressively low voltage to work, though, and [J.G.] has put a few of them to work in this battery-powered audio tube amplifier.

The key to the build is the Russian-made 2SH27L battery tubes which are originally designed in Germany for high-frequency applications but can be made to work for audio amplification in a pinch. The power amplifier section also makes use of 2P29L tubes, which have similar characteristics as far as power draw is concerned. Normally, vacuum tubes rely on a resistive heater to eject electrons from a conductive surface, which can involve large amounts of power, but both of these types of tubes are designed to achieve this effect with only 2.2 volts provided to the heaters.

[J.G.] is powering this amplifier with a battery outputting 5V via a USB connection, and driving a fairly standard set of speakers borrowed from a computer. While there aren’t any audio files for us to hear, it certainly looks impressive. And, as it is getting harder and harder to find vacuum tubes nowadays, if you’re determined to build your own amplifier anyway take a look at this one which uses vacuum tubes built from scratch.