Open Laser Blaster Shells Out More Bang For The Buck

[a-RN-au-D] was looking for something fun to do with his son and dreamed up a laser blaster game that ought to put him in the running for father of the year. It was originally just going to be made of cardboard, but you know how these things go. We’re happy the design went this far, because that blaster looks fantastic.

Both the blaster and the target run on Arduino Nanos. There’s a 5mW laser module in the blaster, and a speaker for playing the pew pew-related sounds of your choice. Fire away on the blaster button, and the laser hits a light-dependent resistor mounted in the middle of the target. When the target registers a hit, it swings backward on a 9g servo and then returns quickly to vertical for the next shot.

There are some less obvious features that really make this game a hit. The blaster can run in 10-shooter mode (or 6, or whatever you change it to in the code) with a built-in reload delay, or it can be set to fully automatic. If you’re short on space or just get sick of moving the target to different flat surfaces, it can be mounted on the wall instead — the target moves forward when hit and then resets back to flat. Check out the demo video we loaded up after the break.

No printer? No problem — here’s a Node-RED shooting gallery that uses simple wooden targets.

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Measuring The Speed Of Light In 1927

It is hard to remember that a lot of high tech research went on well before the arrival of electronic computers, lasers, and all the other things that used to be amazing but are now commonplace. That’s why we enjoyed [Michel van Biezen’s] two part post on how Michelson computed the speed of light in 1927. You can see the videos below.

Michelson wasn’t the first, of course. Galileo tried. He sent an assistant to the top of a hill with a lantern. When the assistant saw Galileo’s lantern, he was to uncover his lantern. They practiced near each other to account for reaction time. But when the assistant was 3 km away, it didn’t take any more time. The implication was that light traveled instantaneously, but, of course, it is actually just really fast.

By 1927, Michelson tried what was in effect the same technique but with better technology, and this time they put a reflector about 35 km away meaning the light had to go to the reflector and back for a total of about 70 km.

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The Auto-Bartender

It’s the end of the academic semester for many students around the globe, so here comes the flurry of DIY projects. Always a great time to check out all the cool hacks from our readers all over the world. One project that piques our interest comes courtesy of [Jason Ummel] and his Auto-Bartender. (Video, embedded below.)

[Jason] developed this project as a part of his robotics class taught by Professor Martinez, one of our friends at FlexiLab. Powered by one of our favorite microcontrollers, the ATmega328, the Auto-Bartender is driven by a single 12 V motor coupled with 10 individual valves for separate drinks. Drinks are pumped into a cup sitting on top of a scale, allowing the device to know how much of each drink has been dispensed. The entire setup is controlled using a smartphone application developed in MIT App Inventor, a super-easy way to prototype Android applications.

Furthermore, [Jason] incorporated a number of user-centered design considerations into his project. These include an LCD to display updates, a green LED to indicate the device is in progress, and a buzzer to let the user know the drink is complete.

We really like the combination of craftsmanship, electronics hardware design, and software development that [Jason] put into his project. It’s the kind of project we know our readers will enjoy.

It looks like Jason substituted tap water for Whiskey and Dr. Pepper for his demo. Not exactly what we had in mind, but I guess he still has exams to finish.

Cool project [Jason]! We can’t wait to see Auto-Bartender on Hackaday.io.

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These LED Shades Will Blind You With Science

Unless you’re particularly fond of looking at the back of 88 individual WS2812B LEDs, these “RGB Goggles” from [Mukesh Sankhla] won’t offer you much of a view. But from an outsider’s perspective, the smartphone-controlled glasses certainly make a statement. Just don’t try to operate any heavy machinery while wearing them.

The build starts off with a pair of shades dark enough that the lights won’t be obvious until they’re powered up. [Mukesh] then carefully aligned the LEDs into a grid pattern on a piece of clear tape so they could be soldered together with the fewest number of jumper wires possible. Even if you’re not in the market for some technicolor eyewear, this clever arrangement of WS2812B modules could come in handy if you’re looking to make impromptu LED panels.

To control the LEDs, [Mukesh] is using an Arduino Nano and an HC-06 Bluetooth module that’s linked to an application running on an Android smartphone. The software, developed with the MIT App Inventor, allows the user to easily switch between various patterns and animations on the fly. With such an easy-to-use interface, the RGB Goggles don’t look far off from a commercial product; other than the whole not being able to actually see through the thing.

We’ve actually seen a number of custom glasses projects over the years, as it seems that a cheap pair of shades make an ideal platform for head-mounted hacks. We’ve even found what may be the ideal power source for them.

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Automated Pancake Making For Devotees Of Fluffy Pancakes

We have a weakness for automated pancake machines here at Hackaday, but in terms of complete pancake machines rather than CNC batter printers we’re surprised to see more from the rest of the world than we do from the USA. Perhaps this has something to do with differences in opinion on what constitutes a pancake, whether the moniker should be applied to a large and thin disk of cooked batter, or to a smaller, thicker, and fluffier variety. For Europeans only the former will do, while for Americans anything but the latter is simply crêpe. To restore American honour in the world of automated pancakes then, a team of students from Kennesaw State University in Georgia, USA, have built a pancake vending machine for fluffy American-style pancakes as part of their coursework.

Sadly for the team the COVID-19 pandemic put a stop to their lab work and stopped them making a fully functional vending machine, but the important part of robotic pancake making is something they’ve completely nailed. In the video below the break we see them testing various batter mixes before developing their mixer and batter delivery system, and finally a robotic flipper that cooks the pancakes on a griddle and delivers them to a plate.  It also has the unexpected benefit of stacking pancakes.

We’re sure that without the pandemic they would have made a fully-functional vending machine for lucky Georgia students to sate their appetites upon. Meanwhile for pancake-crazy readers, here are complete pancake making machines from South Africa, and from France.

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Portable MRI Machine Comes To The Patient

To say that the process of installing a magnetic resonance imager in a hospital is a complex task is a serious understatement. Once the approval of regulators is obtained, a process that could take years, architects and engineers have to figure out where the massive machine can be installed. An MRI suite requires a sizable electrical service to be installed, reinforced floors to handle the massive weight of the magnet, and special shielding in the walls and ceiling. And once the millions have been spent and the whole thing is up and running, there are ongoing safety concerns when working around a gigantic magnet that can suck ferromagnetic objects into it at any time.

MRI studies can reveal details of diseases and injuries that no other imaging modality can match, which justifies the massive capital investments hospitals make to obtain them. But what if MRI scanners could be miniaturized? Is there something inherent in the technology that makes them so massive and so expensive that many institutions are priced out of the market? Or has technology advanced far enough that a truly portable MRI?

It turns out that yes, an inexpensive MRI scanner is not only possible, but can be made portable enough to wheel into a patient care room. It’s not without compromise, but such a device could make a huge impact on diagnostic medicine and extend MRI technologies into places far beyond the traditional hospital setting.

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Hackaday Podcast 066: The Audio Overdub Episode; Tape Loop Scratcher, Typewriter Simulator, And Relay Adder

Hackaday editors Elliot Williams and Mike Szczys stomp through a forest full of highly evolved hardware hacks. This week seems particularly plump with audio-related projects, like the thwack-tackular soldenoid typewriter simulator. But it’s the tape-loop scratcher that steals our hearts; an instrument that’s kind of two-turntables-and-a-microphone meets melloman. We hear the clicks of 10-bit numbers falling into place in a delightful adder, and follow it up with the beeps and sweeps of a smartphone-based metal detector.

Direct download (~60 MB)

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