DIY Mini Fridge Is Pure Brilliance In Foam

There’s nothing more pleasing on a hot day than an ice-cold beverage. While the vast majority of us have a fridge in the kitchen, sometimes it’s desirable to have a further fridge in the lab, games room, or workshop. To that end, you may find value in this ultra-cheap, low-cost DIY fridge build from [Handy_Bear].

Like many tiny fridge builds, this design eschews complex gas-cycle refrigeration techniques for simple Peltier modules. These are devices that have one cold side and one hot side, because they move heat when electricity is applied. This build uses a Peltier module fitted with a fan to better shift away heat from the hot side, improving the module’s cooling ability.

The “fridge” itself is assembled out of thick XPS insulation foam. A hot wire cutter was used to cut several slabs which were then assembled using hot glue. The Peltier module is installed on the back, at the top of the fridge. Thus, air which is cooled in this area will then travel down through the rest of the fridge’s cavity. [Handy_Bear] also goes over how to produce a working hinge and a gasket for the door, which helps with ease-of-use and efficiency. As a nice touch, a set of 12V LED lights are also installed inside, which light when the door is open. Just like the real thing!

The final build is noisy, slow to cool down, and it uses 60 watts of power to cool down just two regulation-sized sodas. Notably, you could fit two standard NATO smoke grenades in the same space, as they’re almost-identically sized (ask us how we know). However, smoke grenades don’t usually need to be refrigerated.

None of that means it isn’t fun though! Plus, [Handy_Bear] notes that adding a second Peltier would greatly aid the fridge’s ability to quickly chill your grenades sodas. You might even like to explore the use of special fan designs to make the fridge even quieter! Video after the break.

Continue reading “DIY Mini Fridge Is Pure Brilliance In Foam”

A black chandelier that looks somewhat like a fern frond. It has four lights arranged roughly in a circle around the curly end and two clustered near the tail. It is mounted on a dark wood panel ceiling.

Put A Constellation In Your Dining Room

We love lamps here at Hackaday, especially if they imitate natural light sources. [Scott McIndoe] used his love of lamps to fashion a chandelier replicating his favorite constellation, the Southern Cross.

Starting with the Southern Cross’s four major stars and the pointers of Alpha and Beta Centauri, [McIndoe] sketched out a breaking wave form between the six stars to form the spine of this light source. By using smart bulbs for each of the six star positions, he was able to set a scene that replicates the color and relative brightness of each star for that extra astronomical touch.

The top and bottom of the chandelier is laser cut from 3 mm plywood and fitted together using glue and finger joints while the sides are a wood veneer. The entire piece was sanded and coated with a bit of filler before painting. Mounting is accomplished using three eye hooks mounted on the top side of the chandelier.

If you want more celestial lamps, check out [McIndoe]’s previously-featured analemma chandelier or this lithophane moon lamp.

A Low Budget DIY Vibrotactile Stimulator For Experimental CRS

Modern techniques of Coordinated Reset Stimulation (CRS), which is usually administered with invasive deep brain stimulation, can have a miraculous effect on those suffering from Parkinson’s disease. However, the CRS technique can also apparently be administered via so-called vibrotactile CRS (vCRS) which essentially means vibrating certain nerve endings corresponding to brain regions that have a large cortical representation.

An example is vibrating the tips of the fingers using special gloves. This is a medical technique and as such is governed by the FDA. With ongoing trials, patients all around the world will simply have to wait. [HackyDev] has been working with a group of people on developing an open source vCRS glove.

This neuromodulation technique seems so promising, that this upfront effort by hackers around the world is simply a joy to see. Patents be dammed; we can work around them. Interested parties can follow the (very long, tricky-to-follow) thread here.

The hardware [HackyDev] put together uses a nodeMCU as the controller, driving eight motor coils via MOSFETS. The finger-mounted actuators are constructed by ripping the electromagnet out of a relay and mounting it in a 3D printed frame, with a magnet suspended on a spring. This part is mounted on each finger. The nodeMCU presents a simple web form that enables the configuration of the pulse parameters.

A permanent magnet is housed in the spring’s top section

The way the gloves appear to work is due to the way the body perceives sensory input, with a massive bias towards the hands and mouth region, referred to as the cortical homunculus. Each finger has an individual haptic element, which is actuated in a specific sequence with a carefully formed pulse at approx. 250 Hz.

This appears to activate similar in-brain effects as traditional (and invasive) DBS therapy by effectively de-synchronizing certain over-synchronized brain pathways and alleviating the overactive ß-wave activity in the brain. And this calms the tremors as well as many other PD symptoms. It’s all very exciting stuff, and we’ll be following this story closely.

For more on the backstory check out the 2017 paper by Peter A. Tass, as well as this later one, and this one. We’ve seen some recent success with diagnosing or at least detecting PD, by smell as well as via audio, so the future might look a little brighter for quite a number of people.

LED Filament Lamp Is Subtle, Warm, And Elegant

Hackers have loved LEDs from day one, back when they gave us little more than a dim spot of colored light in the darkness. These days, they’re big, bright, and beautiful, and can be used to create some exquisite lighting fixtures. This lamp build from [lonesoulsurfer] is a great example of that.

The build uses LED filaments, which have grown popular for the way they emulate old-fashioned Edison filament bulbs. The filaments consist of tiny LEDs all in a row, covered in flexible material to allow them to act like a filament. They’ll happily power up from just 3V, and deliver great brightness and lovely warm light.

[lonesoulsurfer] bent up an elegant oval-shaped frame for the lamp, using common brass tubing. In the middle of the are two lengths of white plastic tubing with the LEDs inside. The brass is painted black, with the LEDs providing two bright glowing lines on the arms of the oval. The base is then made out of wood and copper tubing, providing a pop of material contrast to the rest of the frame.

It’s an elegant build, and one you can readily recreate at home. If you do so with enough finesse, it will stunt on anything Ikea or (Australian) Kmart has put out in the last decade, in both material quality and uniqueness. We do love a good lamp build around these parts, after all. Video after the break.

Continue reading “LED Filament Lamp Is Subtle, Warm, And Elegant”

The USAF (Almost) Declares War On Illinois Radio Amateurs

Every week the Hackaday editors gather online to discuss the tech stories of the moment, and among the topics this week was the balloons shot down over North America that are thought to be Chinese spying devices. Among the banter came the amusing thought that enterprising trolls on the Pacific rim could launch balloons to keep the fearless defenders of American skies firing off missiles into the beyond.

But humor may have overshadowed by events, because it seems one of the craft they shot down was just that. It wasn’t a troll though, the evidence points to an amateur radio pico balloon — a helium-filled Mylar party balloon with a tiny solar-powered WSPR transmitter as its payload.

The balloon thought to have been shot down was launched by the Northern Illinois Bottlecap Balloon Brigade, a group of radio amateurs who launch small helium-filled Mylar balloons carrying the barest minimum for a solar-powered WSPR beacon. Its callsign was K9YO, and having circumnavigated the globe seven times since its launch on the 10th of October it was last seen off Alaska on February 11th. Its projected course and timing tallies with the craft reported shot down by the US Air Force, so it seems the military used hundreds of thousands of dollars-worth of high-tech weaponry to shoot down a few tens of dollars worth of hobby electronics they could have readily tracked online. We love the smell of napalm in the morning!

Their website has a host of technical information on the balloons and the beacons, providing a fascinating insight into this facet of amateur radio that is well worth a read in itself. The full technical details of the USAF missile system used to shoot them down, sadly remains classified.

Stair Climbing Rover Gets Up With Rocker Bogies

Doctor Who eventually made light of the fact that the Daleks were critically impaired when it came to staircases. This rover from [WildWillyRobots] doesn’t share that issue, thanks to a smart suspension design.

The rover itself is built using 3D printed components for everything from the enclosure, to the suspension system, as well as the wheels themselves. It uses a rocker-bogie design, which NASA designed for Mars-bound rovers and we often see copied for terrestrial applications. Gear motors are used for their plentiful torque, and they are placed directly within the wheels. Servos allow the individual wheels to be steered, allowing the rover to crab sideways and perform zero-radius turns.

The rocker-bogie setup does a great job of keeping the rover’s wheels touching the ground, even over rough terrain. It readily tackles a random pile of bricks with ease, in a way that many four-wheeled designs would struggle to match. Given its trials on Mars, it’s easy to call the rocker-bogie setup a thoroughly-proven design.

We’ve featured plenty of other rocker-bogie builds in the past; many of them are 3D printed as well.

Continue reading “Stair Climbing Rover Gets Up With Rocker Bogies”

A Call For Better Shower Temperature Controls

A good shower is a beautiful, rejuvenating experience. Contrarily, a shower that’s either too hot or too cold becomes a harrowing trial of endurance. [Ben Holmen] has been musing on the way we control temperature in our showers, and he has come to the conclusion that it’s not good enough. He’s done the math, quantified the problem, and is calling for better solutions for all.

[Ben]’s plot of shower temperature vs. mixer tap angle.
[Ben]’s complaint rests with the mixer taps that have become the norm in modern shower installations. These taps have a 180-degree range of motion. On one end, you get maximum cold water output, on the other, maximum hot water output. This is fine for a kitchen sink where we often want one extreme or the other, and exact temperature isn’t important. However, for a shower, it’s terrible.

By [Ben]’s measurements, just a 10-degree range on his own shower tap corresponds to comfortable, usable temperatures. That’s means just 5.6% of the control range is devoted to temperatures the user is likely to select. His argument goes that this is the opposite of how it should work, and that most of the tap’s range should be dedicated to comfortable temperatures.

Ideal water temperature curve, compared to standard tap.

This would allow much finer control of shower temperature in the actual useful range. It would allow us to make tweaks to our shower temperature without having to ever-so-delicately nudge the mixer tap. Extreme hot and extreme cold temperatures should still be available, but left at the utter extremes.

Sadly, [Ben] doesn’t work for Big Tap, so he can’t directly influence the product sold to the public. Instead, he’s calling for manufacturers to develop shower valves that prioritize the temperatures that humans desire most. Unfortunately, it’s not immediately clear how the mechanics of such a valve would work without adding considerable cost and complexity when compared to the traditional model.

What do you think? Are things fine the way they are, or does [Ben] have a point? Perhaps you’re a two-tap evangelist! In any case, we’d love to hear your comments below. Meanwhile, if you’re more worried about the water bill than the temperature, we can help you there as well!