Rocket Stove Efficiently Heats Water

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.

Continue reading “Rocket Stove Efficiently Heats Water”

Turning A Window Air Conditioning Unit Into Whole-House AC

Although air conditioning units are generally subdivided into a number of categories, including window, split and whole house/building units, they still work the same, with the compressor, condenser and expansion stages.

Extending the wiring for the AC unit’s controller board (Credit: HowToLou)

In the case of widely available window AC units you can indeed use them as designed in a window, or as [HowToLou] is in the process of demonstrating, as a whole-house AC unit. The main thing to keep an eye out for here is the rated capacity of the window AC unit (in British Thermal Units, square meters/feet). In this case [Lou] used a pretty beefy $600, 24,000 BTU window unit that should be good for about 1200 sqf (~111 m2) .

Most of the modifications are pretty straightforward, with the control board needing to have its wiring extended, as well as the AC unit’s air intake and exhaust on the indoors side. The unit is then placed outside on a stable foundation and inserted into a suitably sized hole in the side of the building, with the controller’s cable running to it from indoors. For the next step, [Lou] intends to connect the air channels on the AC unit to the house’s furnace ducts, to complete the whole-house AC installation.

Compared to a regular whole-house AC unit, this DIY approach has the advantage of anyone being able to just buy and install a window AC unit, whereas whole-house AC tends to require a licensed installer and a lot of additional costs. How well [Lou]’s DIY approach ends up working will hopefully be revealed in a Part 2.

Continue reading “Turning A Window Air Conditioning Unit Into Whole-House AC”

Pizza Elevator Is The Most Vital Pandemic Technology Of All

Remember the darkest days of lockdown and the pandemic? We were trying to distance ourselves from strangers wherever possible. [scealux]’s pizza elevator was spawned at this time to make apartment pizza deliveries as contactless as possible, and it’s charmingly branded to boot.

The build was intended to loft a pizza from street level to a third-floor balcony (by the American convention, ground floor is numbered one). Built with CNC-cut wooden parts, the elevator frame snap-fits on to the balcony railing. From there, a single spool runs out wire to four corners of the elevator platform.

As the crank is turned, the platform lowers under its own weight. The pizza can then be placed on the platform, and dinner can be lifted back up to the apartment. It’s a simple design, and one that manages to lift the pizza in a stable and flat fashion. With that said, we’d still like to see some anti-tip railings on a potential revision two.

Mock the branding all you will, it’s actually a smart design choice. The recognizable logo made the device’s purpose super obvious to the pizza delivery person, easing the introduction of the technology to a new user base.

If you want to make your own pizza instead of ordering out, you can automate that too.

Continue reading “Pizza Elevator Is The Most Vital Pandemic Technology Of All”

Denim Epoxy Table Is A Work Of Art

Epoxy has become a hugely popular material in the woodworking and furniture worlds. Who doesn’t love glossy, translucent finishes, after all? [Cam] recently spotted some neat combinations of epoxy with denim, and decided to see if he could replicate the technique to create a very unique desk. We’d say he succeeded.

A significant amount of material was involved, with [Cam] claiming he used 1,000 square feet of denim and 20 gallons of epoxy. The denim was sourced as a bulk roll, making it easy to cut to the proper size to make the desk. Liquid Glass epoxy was used for its visual qualities and its hard-wearing nature.

Combining the two materials was a challenging task. The 50 layers of denim had to be squeegeed one at a time to remove excess epoxy, a process made harder by the thickness of the material. Once all laid up, the stack of denim was compressed between sheets of wood, leading to an epoxy spill of monumental proportions.

Regardless, when the final desk was cleaned up and polished, the results were well worth the trouble. It looks like some kind of crazy denim gem thanks to the rich shine and perfect grain. It’s a material we’d like to play with ourselves.

Continue reading “Denim Epoxy Table Is A Work Of Art”

ESP32 Freezer Alarm Keeps Tabs On Tricky Door

Leaving your freezer door open accidentally is a great way to make a huge mess in the kitchen. [Guy Dupont] had a freezer that would regularly fail to close properly, and was sick of the regular meltdown events. Thus, he whipped up a very digital solution.

The build combines an ESP32 with a reed switch, which is activated by a magnet on the freezer door. If the freezer door is open, the reed switch similarly remains open. The ESP32 checks the switch status every few minutes, and if the door remains open for two consecutive checks, it raises the alarm. A notification is sent to [Guy] via WiFi so that he can rectify the situation. The rig runs off a 400 mAh battery, which lasts for just over three weeks running door checks at two minute  intervals.

Based on [Guy]’s YouTube video, it appears the freezer door is jamming up against the wall. Perhaps shoving the freezer into a better position would help, though we suspect he would have thought of that first. And, in his own words, “That would be a very boring YouTube video, wouldn’t it?”

It’s not the first fridge alarm we’ve featured, and it won’t be the last, refrigeration gods willing.

Continue reading “ESP32 Freezer Alarm Keeps Tabs On Tricky Door”

Smart Powermeter Uses E-Paper Display

In most places around the world, electricity is getting ever more expensive. Cutting back on your usage is one of the easier ways to escape this pain. This smart powermeter from [JGAguagdo] may prove a useful tool to achieve that goal.

The project uses an ESP32-S2 as the brains of the operation. It’s capable of reading up to six current-transformer clamps for measuring current draw in AC devices. It also features an embedded BMP280 temperature and air pressure sensor. Live data is displayed on a 2.9-inch e-Paper display, making it clear and easy to read under normal lighting conditions. By default, it’s set up to display graphs of power usage both over the last 24 hours, and the last ten days. It can even be set up with the prevailing energy rates in your area to display a realistic figure for what you’ll pay for your daily usage.

It can even be set up to work with Home Assistant for more logging and control options. We can imagine that, with a little work, you could even do some fancy plotting of energy use versus temperature to determine the performance and cost of your home HVAC setup.

If you want one with a minimum of fuss, you can score one on Tindie. Alternatively, design files are available on GitHub, too. We’ve featured some other great power meters over the years, and if you’re cooking up your own smart designs, don’t hesitate to let us know!

Awning Motorized And Automated To Avoid Wind Damage

Awnings can be architecturally beautiful, and they provide lovely shelter from the sun and even a bit of rain. They don’t always like taking a pounding from high winds though. [Steve Carey] installed some nice awnings, but wanted to avoid any potential issues, so he built an automated system to extend and retract them for him. 

An ESP32 serves as the brains of the operation. It’s set up to open and close the blinds using a high-torque brushed motor run by a BTS7960 motor driver. The motor turns the awning’s rod via a hook, so it can be readily removed in the event [Steve] moves house. Reed switches are used as end stops to ensure the motor stops when the awning is fully open or closed. The ESP32 is hooked up to an accelerometer mounted on the awning. It’s set up to sum the accelerations detected in all three axes, and close the awning in the event conditions get too windy.

There’s a certain peace of mind that comes with having your awning hooked up with a preventative safety system. We don’t have a lot of awning posts on Hackaday, but we have seen a good number of automated blinds in the past. If you’ve been working on your own outdoor home automation gear, be sure to hit up the tipsline! Happy…awnings…ing? Anyway.