Arduino Nano Runs Battery Spot Welder

March 22, 2016 by 23 Comments

Soldering might look like a tempting and cheap alternative when building or repairing a battery pack, but the heat of the iron could damage the cell, and the resulting connection won’t be as good as a weld. Fortunately, though, a decent spot welder isn’t that tough to build, as [KaeptnBalu] shows us with his Arduino-controlled battery spot welder.

spot_welder_zoomWhen it comes to delivering the high currents necessary for spot welding, the Arduino Nano is not necessarily the first thing that comes to mind. But the need for a precisely controlled welding pulse makes the microcontroller a natural for this build, as long as the current handling is outsourced. In [KaeptnBalu]’s build, he lets an array of beefy MOSFETs on a separate PCB handle the welding current. The high-current wiring is particularly interesting – heavy gauge stranded wire is split in half, formed into a U, tinned, and each leg gets soldered to the MOSFET board. Welding tips are simply solid copper wire, and the whole thing is powered by a car battery, or maybe two if the job needs extra amps. The video below shows the high-quality welds the rig can produce.

Spot welders are a favorite on Hackaday, and we’ve seen both simple and complicated builds. This build hits the sweet spot of complexity and functionality, and having one on hand would open up a lot of battery-hacking possibilities.

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Correcting Color Blindness With DLP Projectors

March 21, 2016 by 51 Comments

About five percent of the population is colorblind to one degree or another, and for them seeing the entire spectrum from Roy to Biv is simply impossible. Their eyes simply don’t have the cones to detect certain colors. The brain is the weirdest machine on the planet, though, and with the right tricks of light, even the colorblind can see more colors than they’re accustomed to. That’s the idea behind [PointyOintment]’s entry for the 2016 Hackaday Prize: color blindness correcting goggles.

Any device that claims to correct color blindness comes with a few caveats and a slightly loose interpretation of what ‘color blindness correcting’ actually is. For the same reason you can’t see deep infrared, someone with color blindness cannot distinguish between two colors; the eye simply doesn’t have the sensors to see a specific color of light. This doesn’t mean the ability to distinguish color in color blind individuals can’t be improved, though. The EnChroma glasses use an optical notch filter to block all colors between blue and green, and between green and red. This works, because the human brain is weird enough and can adapt to nearly anything.

[PointyOintmen] isn’t going with an optical notch filter. He’s using spinning color discs from a DLP projector and 3D ‘shutter’ glasses to present the world in different shades of color many times a second. It’s weird, untested, and will take a few hours to get used to, but it is a very interesting idea. Will it allow color blind people to see more colors? That’s a semantic issue, but if you define ‘seeing color’ as being able to differentiate between two different colors, yes, it will.

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The Infrared Theremin

March 21, 2016 by 4 Comments

The traditional theremin is more or less an audio oscillator with two metal rods. Using proximity sensing, one rod controls the pitch of the oscillator and the other controls the volume. [Teodor Costachiou] apparently asked himself the excellent question: Why does the proximity sensor have to use capacitance? The result is an Arduino-based theremin that uses IR sensors to determine hand position.

[Teodor] used a particular type of Arduino–the Flip and Click–because he wanted to use Click boards for the IR sensors and also to generate sound via an MP3 board based around a VS1053. The trick is that the VS1053 has a realtime MIDI mode, and that’s how this Theremin makes it tones.

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Mobile Text Reader With OCR And Text To Speech

March 21, 2016 by 7 Comments

There are devices out there that will magnify text using fancy cameras and displays, devices that will convert these to Braille, and text-to-speech software has been around for thirty years. For his entry into our Raspberry Pi Zero contest, [Markus] decided to combine all these ideas into a simple device that will turn the printed word into speech.

The impetus for [Markus]’ project came to him in the form of a group of blind computer science  students. These students used a specialized program that used specialized hardware and software such as mobile Braille terminals, OCR, and oral exams that allowed these students to study the same thing as everyone else. [Markus] wanted to produce something similar, using simple text-to-speech software instead of a complicated Braille display.

The physical design of [Markus]’ project is uniquely functional – a hand-held device with a camera up front, a Pi in the middle, and a speaker and headphone jack on the back. The hand grip includes a large battery and a trigger for telling the Pi to read a few words aloud.

The software is built around the SnapPicam and includes a lot of the functionality already needed. OCR is largely a solved problem with Tesseract, and text-to-speech is easy with Festival.

Although [Markus] is just plugging a few existing software modules together, he’s come up with a device that is certainly unique and could be exceptionally useful to anyone with a vision impairment.

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The Raspberry Pi Zero contest is presented by Hackaday and Adafruit. Prizes include Raspberry Pi Zeros from Adafruit and gift cards to The Hackaday Store!
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Critter Twitter Trap Traps Critters, Pings Twitter

March 21, 2016 by 8 Comments

Got aliens in your attic? Squirrels in the skirting board? You need a trap, and [John Mangan] has come up with an interesting way to let you know that you have caught that pesky varmint: the IoT Critter Twitter Trap. By adding a ball switch, Electric Imp and a couple of batteries to a trap, he was able to set the trap to notify him when it caught something over Twitter. To do this, he programmed the Electric Imp to send a message over when a varmint trods on the panel inside the trap, slamming its door shut. The whole thing cost him less than $60 and can be seen in action after the break.

This is a pretty neat hack. I used to help with a Feral Fix program, where feral cats would be trapped, neutered and returned to the wild. This involved baiting the trap, then waiting hours in the cold nearby for the ferals to get comfortable enough to climb inside and trigger the trap. [John’s] version would only work indoors (as it uses WiFi), but it wouldn’t be that difficult to add a cell phone dongle or other RF solution to extend the range. With this hack, I could have at least waited somewhere warmer, while the trap would ping me when it was triggered.

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Raspberry Pi Zero Contest Grand Prize Winners!

March 21, 2016 by 17 Comments

The Raspberry Pi Zero Contest presented by Adafruit and Hackaday came to a close last week, as the clock struck 11:59 am on Sunday, March 13, 2016. Since then our team of judges has been working to pick the top three entries. It was a hard job sorting through nearly 150 amazing creations.  In the end though, the judges were able to pick three grand prize winners. Each winner will receive a $100 gift card to The Hackaday Store.  So let’s get to the winners!

[JohSchneider] and [Markus Dieterle] both won Pi Zero boards and went on to win $100 gift certificates. [shlonkin] didn’t win a Pi Zero, but persevered and continued working on the classroom music teaching aid even without a Zero board. The top winners aren’t the only ones who are doing well. Everyone who entered has a head start on a great project for The 2016 Hackaday Prize.

I’d like to thank Hackaday’s own [Dan Maloney], [Kristina Panos], [Sophi Kravitz] and [Brian Benchoff] who joined me to judge the contest. The entire Hackaday staff is indebted to [Limor Fried] and [Phil Torrone] over at  Adafruit for coming up with 10 live videos, and providing 10 hard to find Pi Zero boards for our winners. The biggest thanks go to the entrants. If I could send a prize out to each and every one of you, I would!

The Hacker’s Notebook: A Mission Log For Every Project

March 21, 2016 by 46 Comments

While “writing it down” might seem like common sense, it wasn’t always the case. From the times of Ancient Greece, Plato tells a story of a worried Egyptian King, who, upon witnessing the invention of writing, remarks,

“If men learn this, it will implant forgetfulness in their souls; they will cease to exercise memory because they rely on that which is written, calling things to remembrance no longer from within themselves, but by means of external marks. [1]”

To some, the notebook was a dangerous device, a thief that would rob us of our memories [2]. Fortunately, these days, there’s plenty of evidence from our Psych texts that say we humans are pretty shabby at keeping the facts straight. In fact, each time we recall a memory, we change it! Here lies the beauty of the notebook. Have an idea for a new project? Why not log it somewhere for future reference? With diligence, the notebook can become our own personal hub for spurring on new project ideas.

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