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 a nifty 3D printed box up top to do some math and display the number of cans remaining as a simple bar graph. The sensor reads one bay, and the code multiplies by two to get the total. It was touch and go there for a minute as he wasn’t sure that the HC-SR04s would get a good response from the cylindrical cans. Not only did they give a good reading, the first test was quite accurate.

[Chris] recently finished Mk. II, which replaces the momentary (and the Coke logo) with a second HC-SR04. The first version required the push of a button to do inventory, but now he simply walks up to the machine and knows at a glance if it’s time to make a beer run.

Okay, so maybe you don’t have cool old Coke machine problems. But surely you can find something that needs pinging, like an inconvenient rain barrel.

It’s A Nixie! It’s A VFD! No, It’s A Custom LED Display In A Tube

Like the look of Nixies but they just seem a little overdone? Or perhaps you just don’t want the hassles of a high-voltage power supply? Then maybe these faux-Nixie LED “tube” displays will find a way into your next clock build.

For his 2018 Hackaday Prize entry, [bobricius] decided that what the world needs is a Nixie that’s not a Nixie. To that end, each display is formed by seven surface-mount LEDs soldered to a seven-segment shaped PCB and slipped into a glass tube. The LEDs are in 4014 packages so they’re only 4 millimeters long, but what they lack in size they make up for in brightness. We’re not sure if it’s a trick of the camera, but the LEDs certainly seem to put off a bluish glow that’s reminiscent of vacuum-fluorescent displays — it’s like a Nixie and a VFD all rolled up in one package.  The current case, which hides the clock circuitry on the lower part of the PCB, is just plastic, but this would look spiffy in a fine wooden case.

Could this be another Nixie tube killer that never was? Perhaps, but wherever it ends up, we like the look of it, and we’re glad it’s one of the early Hackaday Prize entries. Have you got something to enter in the greatest hardware competition on Earth? If not, get cracking!

Cutting Edge Of 3D Printing Revealed At Last Weekend’s Midwest RepRap Festival

The last three days marked the 2018 Midwest RepRap Festival. Every year, the stars of the 3D printing world make it out to Goshen, Indiana for the greatest gathering of 3D printers and printing enthusiasts the world has ever seen. This isn’t like any other 3D printing convention — everyone here needs to take the time to get to Goshen, and that means only the people who want to be here make it out.

Over the weekend we covered some amazing hacks and printer builds from MRRF. The ‘BeagleBone On A Chip’ has become a complete solution for a 3D printer controller. This is a great development that takes advantage of the very under-used Programmable Real-Time Units found in the BeagleBone, and will make an excellent controller for that custom printer you’ve been wanting to build. E3D has announced they’re working on an automatic tool-changing printer. It’s a slight derivative of their now-defunct BigBox printer, but is quite possibly the best answer to multi-material filament printers we’ve ever seen. There’s some interest from the community, and if everything goes well, this printer may become a kit, or something of the sort. Filament splicing robots also made an appearance at this year’s MRRF, and the results are extremely impressive. Now you can create multi-color prints with the printer you already own. Is it expensive? Yes, but it looks so good.

This wasn’t all that could be found at MRRF. There were hundreds of printers at the event, and at last count, over 1300 attendees. That’s amazing for a 3D printer convention that is held every year in the middle of nowhere, Indiana. What were the coolest sights and sounds coming out of MRRF this year? Check out the best-of list below.

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A Resistor Cutting Robot You Can Build

If you’re populating kits, it can get tiring and time consuming. Like all good repetitive processes, it should be automated. As far as cutting resistors goes, this is one way to do it, thanks to [Pablo].

The build is actually cribbed from earlier work by a gang called [oomlout]. Parts for these cutters are made with either lasercut or CNC milled sheet stock. A stepper motor is used to transport the resistor tape, and the cutting blades are moved by standard hobby servos. The use of servos for the blades allows the action to be controlled precisely without having to go to the effort of implementing extra limit switches and circuitry.

Control is by an Arduino Uno, with an A4988 driver controlling the stepper. Servo control is achieved with the Uno’s onboard peripherals. There’s a video below of the machine in operation, which shows it to be a simple and efficient tool for the job.

This build turns an otherwise maddeningly basic chore into a set-and-forget operation. We’ve seen other work in this area before from the [oomlout] team, too. Video after the break.

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Norman Borlaug Saves A Billion

Everyone loves a hero. Save someone from a burning building, and you’ll get your fifteen minutes of fame. That’s why I’m always surprised that more people don’t know Norman Borlaug, who would have celebrated his 104th birthday on Sunday. He won the Nobel prize in 1970 and there’s good reason to think that his hacking efforts saved about a billion people from starving to death. A billion people. That’s not just a hero, that’s a superhero.

To understand why that claim is made, you have to go back to the 1970s. The population was growing and was approaching an unprecedented four billion people. Common wisdom was that the Earth couldn’t sustain that many people. Concerns about pollution were rampant and there were many influential thinkers who felt that we would not be able to grow enough food to feed everyone.

Paul Ehrlich, in particular, was a Stanford University biologist who wrote a book “The Population Bomb.” His forecast of hundreds of millions starving to death in the 1970s and 1980s, including 65 million Americans, were taken very seriously. He also predicted doom for India and that England would not exist by the year 2000.

Here we are 40 or 50 years later and while there are hungry people all over the world, there isn’t a global famine of the proportions many people thought was imminent. What happened? People are pretty good problem solvers and Norman Borlaug — along with others — created what’s known as the Green Revolution.

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Robot Uses Iron Man Tech To Walk

Designing a bi-pedal robot is a relatively straight forward task, given the array of tools that we now have at our disposal. There are many open source examples out there for anyone to get started. Designing one that doesn’t fall over a lot… well that’s not so simple. This is because when we walk our center of balance is constantly shifting, so during our adolescence we learn to shift our body weight around to maintain a stable center of balance. By the time we hit our mid-teens most of us have mastered the art of walking, and can maintain stability even through intense movements such as seen in many sports.

The question is of course, how does one convey this type of learning into a bi-pedal robot? It’s not easy to say the least. Take a look at what the robotics team over at Guangdong University of Technology’s School of Automation in China are doing. They’ve strapped a pair of ducted fan jet engines to the feet of a bi-pedal setup. What this does is allow the robot to maintain its center of balance over a large distance. Generally we see bi-pedal robots “tip toe over egg shells” because they need to keep the center of balance as stable as possible. By applying a thrusting force that comes out of the foot; they’re able to maintain center of gravity even though the robot is extended well beyond its normal range of motion.

Be sure to check out the video below for an excellent demonstration. Sometimes Hollywood does hackers a great service by giving us some inspiration!

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Drill Bit Gauge Is Interdenominational Black Magic

Oh, sure – when you buy a new set of drill bits from the store, they come in a handy holder that demarcates all the different sizes neatly. But after a few years when they’ve ended up scattered in the bottom of your toolbox for a while, it becomes useful to have some sort of gauge to measure them. [Caspar] has the solution, and all you need is an old steel rule.

The trick is to get a ruler with gradations for inches and tenths of inches. After cutting the ruler off just after the 6″ point, the two halves are glued together with some steel offcuts and epoxy. By assembling the two halves in a V shape with a 1 mm drill bit at the 1″ position, and a 5 mm drill bit at the 5″ marker, a linear slope is created that can be used to measure any drill bits and rod of the appropriate size inserted between the two.

It’s a handy tool to have around the shop when you’ve amassed a collection of bits over the years, and need to drill your holes accurately. Additionally, it’s more versatile than the usual method of inserting bits in appropriately sized holes, and can be more accurate.

Now that you’ve organised your drill bits, perhaps you’d like to sharpen them?