Misc Hacks

4046 Articles

Measuring Temperature Without A Thermometer

November 2, 2024 by 19 Comments

If you need to measure the temperature of something, chances are good that you could think up half a dozen ways to do it, pretty much all of which would involve some kind of thermometer, thermistor, thermocouple, or other thermo-adjacent device. But what if you need to measure something really hot, hot enough to destroy your instrument? How would you get the job done then?

Should you find yourself in this improbable situation, relax — [Anthony Francis-Jones] has you covered with this calorimetric method for measuring high temperatures. The principle is simple; rather than directly measuring the temperature of the flame, use it to heat up something of known mass and composition and then dunk that object in some water. If you know the amount of water and its temperature before and after, you can figure out how much energy was in the object. From that, you can work backward and calculate the temperature the object must have been at to have that amount of energy.

For the demonstration in the video below, [F-J] dangled a steel ball from a chain into a Bunsen burner flame and dunked it into 150 ml of room-temperature water. After a nice long toasting, the ball went into the drink, raising the temperature by 27 degrees. Knowing the specific heat capacity of water and steel and the mass of each, he worked the numbers and came up with an estimate of about 600°C for the flame. That’s off by a wide margin; typical estimates for a natural gas-powered burner are in the 1,500°C range.

We suspect the main source of error here is not letting the ball and flame come into equilibrium, but no matter — this is mainly intended as a demonstration of calorimetry. It might remind you of bomb calorimetry experiments in high school physics lab, which can also be used to explore human digestive efficiency, if you’re into that sort of thing.

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3D Printed Hardware Sorter Keeps It Simple

November 2, 2024 by 8 Comments

If you’re like us, you’ve got at least one bin dedicated to keeping the random hardware you just can’t bear to part with. In our case it’s mostly populated with the nuts and bolts left over after finishing up a car repair, but however it gets filled, it’s a mess. The degree to which you can tolerate this mess will vary, but for [EmGi], even a moderately untidy pile of bolts was enough to spur this entirely 3D-printed mechanical bolt sorter.

The elements of this machine bear a strong resemblance to a lot of the sorting mechanisms we’ve seen used on automated manufacturing and assembly lines. The process starts with a hopper full of M3 cap head bolts of varying lengths, which are collated by a pair of elevating platforms. These line up the bolts and lift them onto a slotted feed ramp, which lets them dangle by their heads and pushes them into a fixture that moves them through a 90° arc and presents them to a long sorting ramp. The ramp has a series of increasingly longer slots; bolts roll right over the slots until they find the right slot, where they fall into a bin below. Nuts can also feed through the process and get sorted into their own bin.

What we like about [EmGi]’s design is its simplicity. There are no motors, bearings, springs, or other hardware — except for the hardware you’re sorting, of course. The entire machine is manually powered, so you can just grab a handful of hardware and start sorting. True, it can only sort M3 cap head bolts, but we suspect the design could be modified easily for other sizes and styles of fasteners. Check it out in action in the video below.

Just because it’s simple doesn’t mean we don’t like more complicated hardware sorters, like the ones [Christopher Helmke] builds.

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Building A Hydrogen-Powered Foam Dart Cannon

November 1, 2024 by 18 Comments

Nerf blasters are fun and all, but they’re limited by the fact they have to be safe for children to play with. [Flasutie] faced no such restrictions when building his giant 40 mm foam dart launcher, and it’s all the better for it.

This thing is sizeable—maybe two to four times bigger than your typical Nerf blaster. But that’s no surprise, given the size of the foam ammunition it fires. [Flasutie] shows us the construction process on how the 3D-printed blaster is assembled, covering everything from the barrel and body assembly to the chunky magazine. Loading each round into the chamber is a manual process, vaguely akin to a bolt-action mechanism, but simplified.

It’s the method of firing that really caught our eye, though. Each round has a cartridge and a foam projectile. Inside the cartridge is a quantity of flammable HHO gas generated, presumably, from water via electrolysis. The blaster itself provides power to a spark gap in the cartridge that ignites the gas, propelling the projectile through the barrel and out of the blaster.

We’ve seen plenty of Nerf blasters and similar builds around these parts, including some with a truly impressive rate of fire. Video after the break.

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Word Of The Day Calendar Is Great Use Of E-Paper

October 28, 2024 by 10 Comments

If you’re trying to learn a new language, there are always a lot of words to learn. A word-of-the-day calendar can help, and they’re often readily available off the shelf. Or, you can grab some hardware and build your own, as [daedal-tech] did!

The project was built as a gift to help [daedal-tech]’s partner with their efforts to pick up French. Thus, a Raspberry Pi Zero 2W was employed and paired with a small Waveshare e-Paper display. These were stuffed inside a fancy light switch plate from Hobby Lobby and a small stand, the pair of which act as a pretty nice little frame for the build. The Pi runs a small Python script which employs the BeautifulSoup4 library and the Python Image library. Basically, the script grabs French words and spits them out on the display with a small description such that one might understand their meaning.

It’s a simple build, but one that has some real utility and is fun to boot. We might see more word clocks than calendars around these parts, but we love both all the same!

DIY Air Bearings, No Machining Required

October 20, 2024 by 26 Comments

Seeing a heavy load slide around on nearly frictionless air bearings is pretty cool; it’s a little like how the puck levitates on an air hockey table. Commercial air bearings are available, of course, but when you can build these open-source air bearings, why bother buying?

One of the nice things about [Diffraction Limited]’s design is that these bearings can be built using only simple tools. No machining is needed past what can be easily accomplished with a hand drill, thanks to some clever 3D-printed jigs that allow you to drill holes with precision into stainless steel discs you can buy on the cheap. An extremely flat surface is added to the underside of these discs thanks to another jig, some JB Weld epoxy, and a sheet of float glass to serve as an ultra-flat reference. Yet more jigs make it easy to scribe air channels into the flat surface and connect them to the air holes through a bit of plaster of Paris, which acts as a flow restriction. The video below shows the whole process and a demo of the bearings in action.

[Diffraction Limited] mentions a few applications for these air bearings, but the one that interests us most is their potential use in linear bearings; a big CNC cutter using these air bearings would be pretty cool. We seen similar budget-friendly DIY air bearings before, including a set made from used graphite EDM electrodes.

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Ideal Diodes And How To Build Them

October 19, 2024 by 17 Comments

[Julian] knows that real diodes you can buy don’t work exactly like we say they do. That’s actually pretty common. We routinely ignore things like wire resistance and source resistance in batteries. Diodes have problems that are harder to ignore, such as the forward voltage drop. So, while a real diode will only pass current in one direction, it will also drop some of the voltage. [Julian] shows you how you can get simulated ideal diodes and why you might want them in a recent video you can see below.

The video starts with a simple demonstration and enumerates some of the practical limitations. Then, he pulls out some ideal diode modules. These typically don’t solve every problem, so they aren’t really ideal in the theoretical sense. But they typically appear to have no forward voltage drop.

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Power Supply PCB Redesign

October 19, 2024 by 6 Comments

We’ve often heard you should do everything twice. The first time is to learn what you need to do, and the second time is to do it right. We bet [Ian Carey] would agree after taking his old linear power supply PCB and changing it to a switching regulator design. You can see more about the project in the video below.

The first power-up revealed a problem with the 3.3V output. We’ve often thought it is harder to troubleshoot a new design than it is to repair something that is known to have worked at one time.

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