Tales Of Garage Design: Achieving Precision From Imprecise Parts

April 12, 2016 by Sonya Vasquez 48 Comments

Designing parts to fit perfectly together is hard. Whether it’s the coarseness of our fabrication tools or the procedures of the vendor who makes our parts, parts are rarely the exact dimension that we wish they were. Sadly, this is the penalty that we pay by living in a real world: none of our procedures (or even our measurement tools!) are perfect. In a world of imperfect parts, imperfect procedures, and imperfect measurement techniques, how on earth are we supposed to build anything that works? Fortunately, we’re in luck! From the brooding minds of past engineers, comes a suite of design techniques that can combat the imperfections of living in an erroneous world.

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Beating The Casino: There Is No Free Lunch

August 31, 2015 by Voja Antonic 83 Comments

When you are a hardware guy and you live in a time of crisis, sooner or later you find yourself working for some casino equipment company. You become an insider and learn a lot about their tricks. I’ve been in touch with that business for about 30 years. I made a lot of projects for gambling machines which are currently in use, and I had a lot of contact with casino people, both owners and gamblers.

Now I’m sure you expect of me to tell you about the tricks they use to make you spend your money. And I will: there are no technical tricks. This isn’t because they are honest people, but because they don’t need it. Mathematics and Psychology do all the work.

Does the risk of gambling pay off? Mathematically speaking, no – but it’s up to you to decide for yourself. One thing is for certain – whether you decide to gamble or not, it’s good to know how those casino machines work. Know thy enemy.

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Photonic Reset Of The Raspberry Pi 2

February 8, 2015 by Brian Benchoff 102 Comments

For the past month, the Raspberry Pi 2 has only been available to the Raspi Foundation, and for about 2 weeks, select members of the media who have worn the Raspi 2 on a necklace like [Flavor Flav] wears a clock. That’s not many people with real, working hardware and when a product is released, the great unwashed masses will find some really, really weird bugs. The first one to crop up is a light-sensitive reset of the Raspberry Pi 2.

[PeterO] on the Raspberry Pi forums took a few pictures – with flash – of a running Raspberry Pi 2. It took a little bit of deduction to realize that a camera flash will either reset or turn the Raspi 2 off. Yes, this is weird, and experiments are ongoing.

A short video from [Mike Redrobe] confirms the finding and a reddit thread offers an explanation. U16, a small chip located in the power supply part of the Raspi 2, is sensitive to light. Putting enough photons will cause the Pi to shut down or restart.

There’s still some research to be done, however, I can confirm a cheap green laser pointer will reset a Raspberry Pi 2 when the beam is directed at the U16 chip. This is the chip that is responsible, and this is not an EMP issue. This is a photon/light issue with the U16 chip. The solution to this bug is to either keep it in a case, or put a tiny amount of electrical tape over the chip.

Thanks [Arko] for staying up until an ungodly hour and sending this to me.

How A Real 3D Display Works

November 6, 2014 by Brian Benchoff 78 Comments

There’s a new display technique that’s making the blog rounds, and like anything that seems like its torn from [George Lucas]’ cutting room floor, it’s getting a lot of attention. It’s a device that can display voxels in midair, forming low-resolution three-dimensional patterns without any screen, any fog machine, or any reflective medium. It’s really the closest thing to the projectors in a holodeck we’ve seen yet, leading a few people to ask how it’s done.

This isn’t the first time we’ve seen something like this. A few years ago. a similar 3D display technology was demonstrated that used a green laser to display tens of thousands of voxels in a display medium. The same company used this technology to draw white voxels in air, without a smoke machine or anything else for the laser beam to reflect off of. We couldn’t grasp how this worked at the time, but with a little bit of research we can find the relevant documentation.

A system like this was first published in 2006, built upon earlier work that only displayed pixels on a 2D plane. The device worked by taking an infrared Nd:YAG laser, and focusing the beam to an extremely small point. At that point, the atmosphere heats up enough to turn into plasma and turns into a bright, if temporary, point of light. With the laser pulsing several hundred times a second, a picture can be built up with these small plasma bursts.

Moving a ball of plasma around in 2D space is rather easy; all you need are a few mirrors. To get a third dimension to projected 3D images, a lens mounted on a linear rail moves back and forth changing the focal length of the optics setup. It’s an extremely impressive optical setup, but simple enough to get the jist of.

Having a device that projects images with balls of plasma leads to another question: how safe is this thing? There’s no mention of how powerful the laser used in this device is, but in every picture of this projector, people are wearing goggles. In the videos – one is available below – there is something that is obviously missing once you notice it: sound. This projector is creating tiny balls of expanding air hundreds of times per second. We don’t know what it sounds like – or if you can hear it at all – but a constant buzz would limit its application as an advertising medium.

As with any state-of-the-art project where we kinda know how it works, there’s a good chance someone with experience in optics could put something like this together. A normal green laser pointer in a water medium would be much safer than an IR YAG laser, but other than that the door is wide open for a replication of this project.

Thanks [Sean] for sending this in.

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Hacklet 14 – Hacks Around The House

September 5, 2014 by Adam Fabio 25 Comments

In this weeks Hacklet we’re looking at household hacks. Not necessarily globally connected home automation hacks, but task specific hacks that we want in our lives yesterday!

We’ve all had it happen, you’re burning the midnight oil on a project when you realize it’s garbage night. The mad dash to collect empty anti-static bags, last night’s Chinese food, and the rest of the trash before actually venturing outside in the dark.

[Mehmet-cileli] doesn’t have to deal with any of that, thanks to My Bins, his automated trash and recycling can moving system. Normally the bins are stationed near the house. Each garbage night, the system springs into action. The cans and their platform pivots 90 degrees. The entire system then rolls along a track to the curb. Once the cans have been collected, everything rolls back ready for more trash. We just hope [Mehmet’s] garbage men are nice enough to put the bins back on their platform!

Next we have the perfect cup of tea. [Marcel] kept forgetting his tea while it was steeping. After ending up with ink a few times, he built this Automatic Tea Timer. A button starts the timer, and after a few minutes, the tea bag is automatically lifted and a light illuminates to let you know your tea is ready. [Marcel] used a ~~Raspberry Pi~~ ~~Arduino~~ ~~555~~ simple R-C timer circuit to create his delay. The lift arm is a discarded hard drive read arm. The light bulb limits current through the voice coils.

[Juan Sandu] always has veggies with his Smart Small Greenhouse. [Juan] has created a desktop sized greenhouse that gives plants what they crave. No, not Brawndo, we’re talking water, warmth, and light. An Arduino Uno uses sensors to monitor humidity, temperature, light, and moisture. Based upon one of two pre-set plant types, the system determines when to water, turn on lights, or even power up a fan to keep temperatures plant friendly. [Juan] is still working on his greenhouse, but his code is already up on Github.

Next up is [nerwal] with his entry in The Hackaday Prize, GrillUp. GrillUp is a remote grill temperature monitoring system with a cooling spray. Up to 6 food grade thermometers provide GrillUp with its temperature data. If things are getting a bit too hot, Grillup cools the situation down by spraying water, beer, or your favorite marinade. The system is controlled over Bluetooth Low Energy from an android smart phone. A laser pointer helps to aim the water spray. Once the cooling zones are set up, the system runs automatically. It even has a sprinkler mode, where it sprays everything down.

Every hacker’s house needs some Sci-fi mood lights, right? [spetku and maehem] round out this weeks Hacklet with their Fifth Element Stone Mood Lighting. Originally an entry in the Hackaday Sci-fi contest, these mood lights are based on the elemental stones in everyone’s favorite Bruce Willis movie. The lights are 3D printed in sections which stack over foamboard cores. The actual light comes from a trio of RGB LEDs. LED control is from the same brain board which controls the team’s Robot Army. The lights are designed to open up just like the ones in the movie, though fire, earth, wind, and water are not required. The servos [spetku and maehem] selected weren’t quite up to the task, but they mention this will be remedied in a future revision.

That’s a wrap for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hackaday Links: May 18, 2014

May 18, 2014 by Brian Benchoff 9 Comments

Think the original Pong is cool? How about point to point Pong? [v8ltd] did it in three months, soldering all the leads directly to the chip pins. No sockets required. It’s insane, awesome, a masterpiece of craftsmanship, and surprising it works.

[Jeremy Cook] is building a servo-powered light graffiti thing and needed a laser diode. How do you control a laser pointer with a microcontroller? Here’s how. They’re finicky little buggers, but if you get the three-pack from Amazon like [Jeremy] did, you get three chances to get it right.

NFC tags in everything! [Becky] at Adafruit is putting them in everything. Inside 3D printed rings, glued onto rings, and something really clever: glued to your thumbnail with nail polish. Now you can unlock your phone with your thumb instead of your index finger.

Photographs capture still frames, but wouldn’t it be great if a camera could capture moving images? No, we’re not talking about video because this is the Internet where every possible emotion, reaction, and situation can be expressed with an animated GIF. Meet OTTO, the camera that captures animated GIFs! It’s powered by the Raspberry Pi compute module, so that’s interesting.

[Nate] was getting tired of end mills rolling around his bench. That’s a bad thing. He came up with a solution, though: Mill a piece of plywood into a tray to hold end mills.

The Da Vinci printer, a printer that only costs $500 because they’re banking on the Gillette model, has been cracked wide open by resetting the DRM, getting rid of the proprietary host software, and unbricking the device. Now there’s a concerted effort to develop custom firmware for the Da Vinci printer. It’s extraordinarily bare bones right now, but the pins on the microcontroller are mapped, and RepRap firmwares are extremely modular.

Stop Motion Water Droplets

March 1, 2014 by Brian Benchoff 22 Comments

logo

The folks at Physalia studio were asked by a company called IdN to produce a little bit of video with a logo. After tossing a few ideas around, they hit upon the concept of projecting the IdN logo inside a falling water droplet. CGI would never get this idea right, so the finished product is the result of stop-motion animation created inside several thousand falling drops of water.

Taking a picture of a falling water droplet was relatively easy; a small drip, a laser pointer and photodiode, and a flash trigger were all that was needed to freeze a drop of water in time. The impressive part of the build is a motion control system for the camera. This system moves the camera along the vertical axis very slowly, capturing one water droplet at a time.

Behind the droplet is a an animation that’s seemingly inspired by a Rorschach test, ending on the IdN logo. The frames for these animations were printed out and placed inside the test chamber/studio upside down to account for the optical effects of a sphere of water.

The end result is a product of over 20,000 pictures taken, all edited down into a single 30-second shot. An amazing amount of work for such a short video but as you can see in the videos below, it’s well worth the effort.

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