A Bar Graph for Beer Fridge Vitals

[ChrisN219] has an antique Coke machine that used to hold glass bottles. Now it holds around 30 tall boy cans of his favorite post-work suds. The only problem is that [Chris] has no idea how many cans are in it without opening up the door or keeping tally on a nearby slate board. Enter the Arduino.

He wanted to make something completely non-invasive to the machine (phew!) while using as many parts he already had as possible. The result is a simple circuit that uses an ultrasonic sensor mounted inside the machine to ping the depths, and a Nano in …read more

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Pocket-Sized Multiduino Does it All

How many times have you wished for a pocket-sized multimeter? How about a mini microcontroller-based testing rig? Have you ever dared to dream of a device that does both?

Multiduino turns an Arduino Nano into a Swiss Army knife of portable hacking. It can function as an analog multimeter to measure resistance, voltage drop, and continuity. It can also produce PWM signals, read from sensors, do basic calculator functions, and display the health of its rechargeable battery pack.

Stick a 10kΩ pot in the left-side header and you can play a space shooter game, or make line drawings by twisting …read more

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Touchless Shop Doors Over-Engineered to a Blissful Level

When [John Saunders] wanted an automatic door for his shop, rather than settle for a commercial unit, he designed and built a proximity-sensing opener to ease his passing. Sounds simple, right?

Fortunately for us, there are no half-measures at Saunders Machine Works, thanks to the multiple Tormach workcells and the people who know how to use them. The video below treats us to quite a build as a result; the first part is heavy on machining the many parts for the opener, so skip ahead to 8:33 if you’re more interested in the control electronics and programming.

The opener uses …read more

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Wireless Protocol Reverse Engineered to Create Wrist Wearable Mouse

We’ve seen a few near-future sci-fi films recently where computers respond not just to touchscreen gestures but also to broad commands, like swiping a phone to throw its display onto a large flat panel display. It’s a nice metaphor, and if we’re going to see something like it soon, perhaps this wrist-mounted pointing device will be one way to get there.

The video below shows the finished product in action, with the cursor controlled by arm movements. Finger gestures that are very much like handling a real mouse’s buttons are interpreted as clicks. The wearable has a Nano, an MPU6050 …read more

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Arduino BabyTV is Big Fun at Low Resolution

What kind of TV do you have? An older 720p model, or the now standard 1080p? Perhaps you’ve made the leap to the next generation, and are rocking a 4K display in the living room. All those are are fine and dandy if you just want to watch the local sportball contest, but where’s the challenge in that? With all the technology and modular components we have access to anymore, nowadays all the real hackers are making their own TVs.

Of course, when [Nikolai] built his very own LED TV, he did have to make a few concessions. For one …read more

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Smartphone Controlled Periodic Table of Elements

It wouldn’t be much of a stretch to say that here at Hackaday, we’re about as geeky as they come. Having said that, even we were surprised to hear that there are people out there who collect elements. Far be it from us to knock how anyone else wishes to fill their days, but telling somebody at a party that you collect chemical elements is like one step up from saying you’ve got a mold and fungus collection at home. Even then, at least a completed mold and fungus collection won’t be radioactive.

But if you’re going to spend …read more

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Edgytokei: Time On The Edge

Taking inspiration from Japanese nunchucks, [ekaggrat singh kalsi] came up with a brilliant clock that tells time using only hour and minute hands, and of course a base for them to sit on. The hands at certain parts of the hour seem to float in the air, or as he puts it, to sit on their edges, hence the name, the Edgytokei, translating as “edge clock”.

The time is a little difficult to read at first unless you’ve drawn in a clock face with numbers as we’ve done here. 9:02 and 9:54 are simple enough, but 9:20 and 9:33 can …read more

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Final Project for Better Sleep

It’s that time of year again, and students around the world are scrambling (or have already scrambled) to finish their final projects for the semester. And, while studying for finals prevents many from sleeping an adequate amount, [Julia] and [Nick] are seeking to maximize “what little sleep the [Electrical and Computer Engineering] major allows” them by using their final project to measure sleep quality.

To produce a metric for sleep quality, [Julia] and [Nick] set out to measure various sleep-related activities, specifically heart rate, motion and breath frequency. During the night, an Arduino Nano mounted to a glove collects data …read more

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Make A Cheap Muon Detector Using Cosmicwatch

A little over a year ago we’d written about a sub $100 muon detector that MIT doctoral candidate [Spencer Axani] and a few others had put together. At the time there was little more than a paper on arxiv.org about it. Now, a few versions later they’ve refined it to the level of a kit with full instructions for making your own under the banner, CosmicWatch including PCB Gerber files for the two surface mount boards you’ll need to assemble.

What’s a muon? The Earth is under constant bombardment from cosmic rays, most of them being nuclei expelled from supernova …read more

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Hackaday Prize Entry: Dynamometer for Post Stroke Rehabilitation

For those who have suffered a stroke, recovery is a long and slow process that requires rehabilitation to start as early as possible. Quite often, secondary stroke attacks complicate matters. Spasticity — muscle contraction and paresis — muscular weakness, are two of the many common after-effects of stroke. Recovery involves doing repeated exercises to strengthen the muscles and bring back muscle memory. Benchmarking progress becomes difficult when caregivers are only able to use qualitative means such as squeezing tennis balls to monitor improvement. To help provide quantitative measurements in such cases, [Sergei V. Bogdanov] is building a Dynamometer for Post-Stroke …read more

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