Wood And Brass Drink Temperature Monitor Looks Good, Has Class

We’ve all been there. Your current project has hit a wall, or the next step will take days to complete, and you need something to do in the meantime. So you start a project that you envision will fit nicely in the gap, and then, inevitably, it doesn’t. Maybe it even takes so long that the original project gets finished first. So what? There’s nothing wrong with that, especially when the filler project turns out as well as this drink temperature monitor disguised as a circuit sculpture (video, embedded below). Just put your mug on the coaster, and the weight of it activates a hidden switch, which causes the sculpture to display its secret LEDs.

[MakeFunStuff] wanted to make something that looked less like a circuit and more like art, while building a tool that could determine the relative hotness of a beverage. Such a a useful circuit sculpture sounds like a tall order to us, but [MakeFunStuff] pulled it off with finesse and style.

The circuit is based around this Sputnik-looking standalone IR temperature sensor which, as [MakeFunStuff] aptly describes, is “a single-pixel infrared camera that picks up everything in a 90° cone starting at the sensor.”

[MakeFunStuff] paired this easy-to-use sensor with an Arduino Nano and five LEDs that show how hot a beverage is on a scale from 1 to 5. The sensor is hidden in plain sight, suspended from the top of the brass rod sculpture and blending in perfectly. We love that the LEDs are hidden behind a thin layer of carefully-drilled wood and agree that a drill press would have been much easier.

The code is set up for just about every temperature scale from Celsius to Rømer, so that solves that argument. [MakeFunStuff] went with the Kelvin scale because science. Our favorite thing about this video is that [MakeFunStuff] shared their failures and fixes as they built their way toward answering the questions of how to suspend the sensor over the drink, and how best to display the heat level while hiding the electronics. Go grab a hot cup of something and check it out after the break while you let it cool off the normie way.

We admit that we would likely zone out while waiting for the LEDs to disappear. Here’s a smart coaster that uses an ESP8266 to send a message to Discord when your beverage has reached the perfect drinking temperature.

Continue reading “Wood And Brass Drink Temperature Monitor Looks Good, Has Class”

Toggle Switch Puzzle Boggles The Mind, Opens The Box

We all have too much stock of one component or another. Maybe you have more audio pots than you know what to do with, or maybe it’s zener diodes. For [technologyguy], that thing is a pile of toggle switches.  Fortunately he’s always wanted to build a locking box with a binary code that’s laid out in switches — as in, find the right code, and a solenoid unlatches the box. This lovely parts bin special only responds to two combinations out of a possible 4,000+, so anyone who tries to open it should probably block out the afternoon.

Inside you’ll find two 9 V batteries, a home-brew metal latch, a solenoid, and the undersides of four DPDT and eight SPDT toggle switches. If you just picked this thing up and had no idea what was going on, you’d be so screwed as to what to do first. The box needs power, so you’d have to figure out which switch is which. But it’s so much harder than that, because the bottom left switch selects between the two paths that result in an unlocked book-box.

The next two toggles in from the left are on/off selectors for code A and code B, so not only do you have to have the right path chosen, you have to power it, too. The only progress indicators are the LEDs — there’s one for main power, and the other lets you know that the box is unlatched. What a fun conversation piece for the coffee table Zoom-viewable area!

Want to do something far less useful with your throng of toggles? How about a complicated useless machine?

Trick Or Yeet Cannon Will Give Them Candy Shell Shock

One of our favorite things about Halloween is the sheer number of hacks that come out of it each year. This year, hacking is almost a requirement to keep things physically distanced, but that doesn’t mean we can’t have fun. You want fun? How about a candy cannon that launches sweet projectiles at trick-or-treaters from fifty feet?

[Paul McCabe]’s cannon uses a sprinkler valve and an air compressor to launch a pair of fun size candy bars, each encased in a film canister shell. Each trick-or-treater stomps a foot switch fifty feet away at the end of the driveway, and as long as someone is there holding down the primary ignition, the cannon will fire with a nice retort that sounds like a large wind instrument playing a D note.

We were sad to learn that the parachute idea didn’t shake out, but the glow sticks are a great addition for night time. Check out the demo after the break, which is followed by a build video and then some more launches for the fun of it.  Don’t have enough time to build a cannon of this caliber? You could put a spooky six-foot slide together pretty quickly.

Continue reading “Trick Or Yeet Cannon Will Give Them Candy Shell Shock”

Brushless HDD Motor Driver From 9V And Painter’s Tape

Hard drives work by spinning platters full of magnetized data while a read/write head very quickly harvests or changes bits as needed. Older (or perhaps cheaper) drives spin at 5400 RPM, better drives spin at 7200 RPM, and elite drives (that mortals like you never shell out for) spin in the 10k-15k RPM range. This spinning is thanks to a sweet combination of a bearing and a brushless DC motor.

Unfortunately you can’t drive a brushless motor without a brushless motor driver. Well, of course that’s not absolutely true — and [Tommy Callaway] has certainly hacked together a crude exception to the rule. He’s using a 9-volt battery and some blue painters tape to drive a brushless motor.

Brushless motors do their thing by placing permanent magnets on the rotor (the part that spins) and placing multiple stationary coils of wire around it. Brushless motor drivers then energize these coils in a vary carefully timed pattern to continuously push the rotor magnets in the same direction.

[Tommy] wired up his 9V to one of these coils and observed that it holds the rotor in position. He then began playing around with different ways automatically break the circuit to de-energize the coil at just the right time. This means using the spinning center of the hard drive as part of the circuit, with blue painter’s tape in alternating patterns to create the timing. Is this a brushless motor driver, or has he just re-invented the brushed motor?

If this workbench trick leaves you wanting for some hardcore BLCD action, you can’t go wrong with this $20 offering to push motors at very high speeds.

Continue reading “Brushless HDD Motor Driver From 9V And Painter’s Tape”

Build A Foam Cutter Right Now

Cutting foam is difficult with traditional methods. The best way is with a hot wire. If you read Hackaday, it is a good bet you can figure out how to use electricity to make a wire hot without any help. However, there’s something  clever about [MrGear’s] minimal build.

As you can see in the video below, he uses a 9V battery, a clip, some popsicle sticks, and the wire from a ballpoint pen. He also used a switch, but we couldn’t help but think that was unnecessary  since you could just unclip the battery to turn the device on and off. Since he used hot glue to attach the switch to the battery, replacing the battery would be a pain.

Continue reading “Build A Foam Cutter Right Now”

Hackaday Links: February 2, 2014

hackaday-links-chain

[Michel] was in need of a 9V battery connector, and in a brilliant bit of insight realized 9V batteries will plug directly into other 9V batteries (just… don’t do that. ever.) Taking a dead 9V, he tore it open, was disappointed by the lack of AAAA cells, and soldered some wires onto the connector.

Sometimes a project starts off as a reasonable endeavour, but quickly becomes something much more awesome. [Wallyman] started off building a hammock stand and ended up making a giant slingshot. We’re not one to argue with something that just became a million times more fun.

We’ve seen solder stencils made out of laser-cut metal, photoetched metal, plastic cut on a vinyl cutter, laser-cut plastic, and now finally one made on a 3D printer. It’s a pretty simple process – get the tCream layer into a .DXF file, then subtract it from a plastic plate in OpenSCAD.

Apple loves their proprietary screws, and when [Jim] tried to open his Macbook Air with the pentalobe screwdriver that came with an iPhone repair kit, he found it was too large. No problem, then: just grind it down. Now if only someone could tell us why a laptop uses smaller screws than a phone…

[Victor] has been playing around with an RTLSDR USB TV tuner dongle for a few months now. It’s a great tool, but the USB thumb drive form factor wasn’t sitting well with him. To fix that, he stuck everything into a classy painted Hammond 1590A enclosure. It looks much cooler, and now [Victor] can waterproof his toy and add a ferrite to clean things up.