Building A Devil’s Toothpaste Rocket Motor

October 21, 2021 by 25 Comments

When it comes to weird and wacky homebrew rocket experiments, [Integza] keeps himself fairly busy. He’s now attempted a design repurposing Devil’s Toothpaste for propulsion.

Devil’s Toothpaste is really the same as the famous Elephant Toothpaste experiment, just executed with higher concentration hydrogen peroxide. In this case, [Integza] is using 50% hydrogen peroxide combined with potassium permanganate as a catalyst. When the two are combined, the hydrogen peroxide breaks down into oxygen and water, which [Integza] uses here to propel a skateboard.

The potassium permanganate catalyst is impregnated into 3D printed porous ceramic parts. The peroxide is then  injected into this matrix via a compressed air mechanism, where it decomposes, creating a jet of water and oxygen that then blasts out of a 3D printed rocket nozzle to generate thrust.

It works surprisingly well, even if it’s a messy and unconventional way to build a rocket. It’s also a lot less fiery than most of [Integza]’s previous projects. Video after the break.

Continue reading “Building A Devil’s Toothpaste Rocket Motor” →

Smokeless Burn Barrel Makes Your Backyard Fire Much Cleaner

October 21, 2021 by 80 Comments

Old 55-gallon drums are often repurposed into fire barrels with the simple addition of a few holes cut into the walls. Generally, they’re fit enough for purpose but can have a very smoky output, particularly when overloaded.  However, this design from [Building Stuff Is Fun] combines two drums into one to create a barrel that burns far more efficiently with less smoke! (Video, embedded below.)

Note the vent holes feeding oxygen to the fire just before the barrel outlet.

Through some clever cuts and folding of steel, a single burn barrel is created from the original two that helps eliminate smoke entirely, through two clever design features. First of all, plentiful air is provided to the fire thanks to the intakes at the bottom of the barrel. Secondly, the barrel-in-barrel design, paired with some smart vents, helps provide fresh air to the fire just before it leaves the barrel. This extra oxygen supply helps create secondary combustion at the outlet which burns up all the matter that would normally be passed out as smoke.

The design involves a lot more work than just hacking some holes in an old drum, but the results are undeniably impressive. The output of the smokeless burn barrel looks far hotter and cleaner. We’ve seen similar designs used to supply workshop heat, too. Video after the break.

Continue reading “Smokeless Burn Barrel Makes Your Backyard Fire Much Cleaner” →

Going Forward To The Land: Technology For Permaculture

October 21, 2021 by 34 Comments

It’s usual for a Hackaday scribe to read hundreds of web pages over a typical week as we traverse the world in search of the good stuff to bring you. Sometimes they’re obvious Hackaday stories but as you’ll all no doubt understand we often end up on wild tangents learning about stuff we never expected to be excited about. Thus it was last week that I happened upon a GQ piece charting the dwindling remains of the communes set up in rural California by hippies during the counterculture years.

With only a few ageing residents who truly embraced the back-to-the-land dream remaining, these adventurously-designed home-made houses are gently decaying into the forest. It’s a disappearing world, but it’s also close to home for me as someone who crew up on a self-sufficiency smallholding in the 1970s. My parents may not have been hippies in the way those of everyone else in that scene at the time seemed to be, but I learned all my curiosity and hacking skills in the many opportunities presented to a small child by an unruly combination of small farm and metalworking business. There’s part of me that would build a hippy home in a Californian forest in a heartbeat, and throw myself with gusto into subsistence vegetable growing to get me through each winter.

Continue reading “Going Forward To The Land: Technology For Permaculture” →

Announcing The Next Round Of Remoticon Talks

October 21, 2021 by 2 Comments

It’s coming up fast — Hackaday Remoticon 2021 is just a few weeks away, and we’re working around the clock to load up the weekend with awesome and inspiring talks that are bound to get the creative juices racing through your crazy straw brain.

Come and practice your neuroplasticity with us on November 19th and 20th. Remoticon is free-as-in-beer this year, unless you want a t-shirt. Even then, $25 is peanuts, because we’re sure that you’ll find a few talks that are priceless, and you’ll have a cool shirt to remember them by. Grab your ticket right now! We’ll wait.

A few days ago we announced mechanical engineering marvel Jeremy Fielding as our second keynote speaker. Passion is paramount to all projects, and Jeremy’s passion is making things move. He’s a renaissance man with a quiver full of self-taught skills, and is sure to bring enthusiasm to his keynote talk, which focuses on building hardware that moves, and how to handle the mechatronic mysteries that arise when trying to scale things up.

For now, let us indulge you with a preview of the second round of talks and speakers that we’ll be showcasing on November 19th and 20th. There’s plenty more where these came from, and we’ll be serving up fresh samples all the way until Remoticon weekend.

Continue reading “Announcing The Next Round Of Remoticon Talks” →

3D Printable Scope Probe Adapts To Your Needs

October 21, 2021 by 18 Comments

If there’s one this we electronics engineers are precious about, it’s our test gear. The instruments themselves can be obscenely expensive, since all that R&D effort needs to be paid back over a much smaller user base compared to say a DVD player. The test probes themselves can often come with an eye-watering price tag as well. Take the oscilloscope probe, pretty much everyone who tinkers with hardware will be familiar with. It’s great for poking around, looking desperately for inspiration when you’re getting stuck in with some debug, but you’ve only got two hands, and that doesn’t leave any spare for button pushing.

Hands-free probing solutions exist, but they can be pricey, flimsy or just a pain to use. Sometimes you just want to solder a wire and leave the probe attached, hoping the grounding lead doesn’t fall off and short something. We’ve seen many solutions to this, so here’s yet another one you can 3D print yourself, so it’s almost free to make.

The two-part 3D printed assembly embeds a pair of wires with a Molex 0008500113 sprung terminal on one end, which can be terminated with your choice of pins, headers or just a pair of plain ‘ol wires. Once you’ve dropped your wiring of choice inside, simply glue the halves with a little cyanoacrylate and you’re good to go. Designed around the Siglent 200MHz PP215 specifically, it is likely compatible with many other brands. Thingiverse only has STL files (sigh!) so it may be tricky to adapt it to your exact probe dimensions, but the idea is good at least.

There is no shortage of electronics probing solutions out there, and boy have we covered a few over the years, here’s a low-cost current probe, an Open Source 2 GHz scope probe, and if you want to get really hacky, look no further for inspiration than the 2019 Hackaday SuperCon SMD Challenge.

Thanks [daniel] for the tip!

A 1971 Thermos compliments this mid-century corner of my office.

The Incredible Tech Of The Vacuum-Seal Flask

October 21, 2021 by 38 Comments

I recently started using a 50-year-old vacuum-seal flask that belonged to my Grandpa so that I don’t have to leave the dungeon as often to procure more caffeine. Besides looking totally awesome on my side desk, this thing still works like new, at least as far as I can tell — it’s older than I am.

Sir James Dewar's original vacuum-seal flask.
Sir James Dewar’s original vacuum-seal flask. Image via the Royal Institute

Of course this got me to wondering how exactly vacuum-seal flasks, better known in household circles as Thermoses work, and how they were invented. The vacuum-seal flask is surprisingly old technology. It was first invented by Scottish chemist Sir James Dewar and presented to the Royal Institute in 1892. Six years later, he would be the first person to liquefy hydrogen and is considered a founding father of cryogenics. Continue reading “The Incredible Tech Of The Vacuum-Seal Flask” →

Build A Moon Phase Clock That Looks Like The Real Thing

October 21, 2021 by 8 Comments

The moon is a beautiful thing that has captivated humanity for centuries, particularly before the advent of television and the Internet when there was nothing else to watch. [JCM_MatSci] developed a clock which tracks the phases of the moon, so you can keep an eye on the state of Earth’s satellite without even having to turn your gaze to a window.

The clock relies on a simplified model of the lunar phases, based around the synodic month which averages 29.530588 days. For non-astronomical purposes, it’s pretty much close enough. The clock uses a high-torque off-the-shelf quartz movement in order to move a 3D-printed geartrain and attached moon assembly. The gears step down the output from the clock to turn the ersatz Moon to display the appropriate phase.

It’s a neat gift for Moon buffs out there, and we’re sure there are still a few even if nobody’s been since 1972. We guess it’s kind of like one of those national parks that everyone loves from their childhood but never visits anymore.

If you have visited the moon recently, however, be sure to drop us a line. We (and a few other million people) have some questions for you.