Hackaday Prize Entry: A PCB To Emulate Coin Cells

September 18, 2017 by 43 Comments

The Coin Cell Emulator CR2016/CR2032 by [bobricius] homes in on a problem some hardware developers don’t realize they have: when working on hardware powered by the near-ubiquitous CR2016 or CR2032 format 3V coin cells, power can be a bit troublesome. Either the device is kept fed with coin cells as needed during development, or the developer installs some breakout wires to provide power from a more convenient source.

[bobricius]’s solution to all this is a small PCB designed to be inserted into most coin cell holders just like the cell itself. It integrates a micro USB connector with a 3V regulator for using USB as an external power source. The board also provides points for attaching alligator clips, should one wish to conveniently measure current consumption. It’s a tool with a purpose, and cleverly uses the physical shape of the PCB itself as an integral part of the function, much like another of [bobricius]’s projects: the Charlieplexed 7-segment LED display.

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AI: This Decade’s Worst Buzz Word

September 18, 2017 by 84 Comments

In hacker circles, the “Internet of Things” is often the object of derision. Do we really need the IoT toaster? But there’s one phrase that — while not new — is really starting to annoy me in its current incarnation: AI or Artificial Intelligence.

The problem isn’t the phrase itself. It used to mean a collection of techniques used to make a computer look like it was smart enough to, say, play a game or hold a simulated conversation. Of course, in the movies it means HAL9000. Lately, though, companies have been overselling the concept and otherwise normal people are taking the bait.

The Alexa Effect

Not to pick on Amazon, but all of the home assistants like Alexa and Google Now tout themselves as AI. By the most classic definition, that’s true. AI techniques include matching natural language to predefined templates. That’s really all these devices are doing today. Granted the neural nets that allow for great speech recognition and reproduction are impressive. But they aren’t true intelligence nor are they even necessarily direct analogs of a human brain.

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A Slew Of NYC Meetups With Tindie And Hackaday This Week

September 18, 2017 by 3 Comments

This is a busy, busy week for Tindie and Hackaday. We’re going to New York, and we have a ton of events planned.

First up is the monthly Hackaday meetup. This time, we’re teaming up with Kickstarter for a pre-Maker Faire Meetup. We’ll be hosting this at Kickstarter’s HQ, and already we have an impressive line of speakers set up to talk about Assistive Technology. These speakers include:

  • Anita Perr and R. Luke Dubois from the NYU Ability Project
  • Andrew Chepaitis from ELIA Life Technology

Also on deck for the for the Hackaday x Kickstarter meetup are live demos from WearWorks, who are developing the WAYBAND, a haptic navigation device and from Elia Frames, a tactile reading system.

The Hackaday x Kickstarter meetup will be Thursday, September 21st, starting at 6:30pm. Here’s the link to RSVP.

This weekend is also World Maker Faire New York and Tindie will be out in force showcasing all the wonderful bits and bobs developed by the Tindie community.

On deck will be [Jasmine] and [Brandon] from Tindie, and of course we’re inviting Tindie sellers to drop by the booth throughout the weekend and showcase their wares.

Also on deck for the World Maker Faire will be [Shulie], [Shayna] and myself. We’ll be tossing brand new Tindie stickers into the audience and giving out Tindie Blinky Badges. If you’ve ever wanted to show your enthusiasm for DIY hardware, now you can with an electronic blinky lapel pin. Solder it up and listen to Benchoff rationalize why it doesn’t need a current limiting resistor! Such fun!

The Science Behind Lithium Cell Characteristics And Safety

September 18, 2017 by 58 Comments

To describe the constraints on developing consumer battery technology as ‘challenging’ is an enormous understatement. The ideal rechargeable battery has conflicting properties – it has to store large amounts of energy, safely release or absorb large amounts of it on demand, and must be unable to release that energy upon failure. It also has to be cheap, nontoxic, lightweight, and scalable.

As a result, consumer battery technologies represent a compromise between competing goals. Modern rechargeable lithium batteries are no exception, although overall they are a marvel of engineering. Mobile technology would not be anywhere near as good as it is today without them. We’re not saying you cannot have cellphones based on lead-acid batteries (in fact the Motorola 2600 ‘Bag Phone’ was one), but you had better have large pockets. Also a stout belt or… some type of harness? It turns out lead is heavy.

The Motorola 2600 ‘bag phone’, with a lead-acid battery. Image CC-BY-SA 3.0 source: Trent021

Rechargeable lithium cells have evolved tremendously over the years since their commercial release in 1991. Early on in their development, small grains plated with lithium metal were used, which had several disadvantages including loss of cell capacity over time, internal short circuits, and fairly high levels of heat generation. To solve these problems, there were two main approaches: the use of polymer electrolytes, and the use of graphite electrodes to contain the lithium ions rather than use lithium metal. From these two approaches, lithium-ion (Li-ion) and lithium-polymer (Li-Po) cells were developed (Vincent, 2009, p. 163). Since then, many different chemistries have been developed.

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Chest Of Drawers Stores Audio Memories

September 18, 2017 by 15 Comments

Some people collect stamps, some collect barbed wire, and some people even collect little bits of silicon and plastic. But the charmingly named [videoschmideo] collects memories, mostly of his travels around the world with his wife. Trinkets and treasures are easy to keep track of, but he found that storing the audio clips he collects a bit more challenging. Until he built this audio memory chest, that is.

Granted, you might not be a collector of something as intangible as audio files, and even if you are, it seems like Google Drive or Dropbox might be the more sensible place to store them. But the sensible way isn’t always the best way, and we really like this idea. Starting with what looks like an old card catalog file — hands up if you’ve ever greedily eyed a defunct card catalog in a library and wondered if it would fit in your shop for parts storage — [videoschmideo] outfitted 16 drawers with sensors to detect when they’re opened. Two of the drawers were replaced by speaker grilles, and an SD card stores all the audio files. When a drawer is opened, a random clip from that memory is played while you look through the seashells, postcards, and what-have-yous. Extra points for using an old-school typewriter for the drawer labels, and for using old card catalog cards for the playlists.

This is a simple idea, but a powerful one, and we really like the execution here. This one manages to simultaneously put us in the mood for some world travel and a trip to a real library.

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A Jet Engine On A Bike. What’s The Worst That Could Happen?

September 18, 2017 by 76 Comments

On today’s edition of ‘don’t try this at home,’ we’re transported to Russia to see [Igor Negoda]’s working jet bicycle.

This standard mountain bike comes equipped with a jet engine capable of 18kg of thrust, fixed to the frame under the seat with an adjustable bracket to change it’s angle as needed. A cell phone is zip-tied to the frame and acts as a speedometer — if it works, it’s not stupid — and an engine controller displays thrust, rpm and temperature.  A LiPo battery is the engine’s power source with a separate, smaller battery for the electronics. The bike is virtually overgrown with wires and tubes that feed the engine, including an auxiliary fuel tank where a water bottle normally resides. Where’s the main fuel tank? In [Negoda]’s backpack, of course.

It certainly kicks up a mean dust cloud and makes a heck of a racket but the real question is: how fast does it go? From the looks of the smartphone, 72 km/h, 45 mph, or 18 rods to the hogshead.

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Better Stepping With 8-Bit Micros

September 17, 2017 by 43 Comments

The electronics for motion control systems, routers, and 3D printers are split into two camps. The first is 8-bit microcontrollers, usually AVRs, and are regarded as being slower and incapable of cool acceleration features. The second camp consists of 32-bit microcontrollers, and these are able to drive a lot of steppers very quickly and very smoothly. While 32-bit micros are obviously the future, there are a few very clever people squeezing the last drops out of 8-bit platforms. That’s what the Buildbotics team did with their ATxmega chip — they’re using a clever application of DMA as counters to drive steppers.

The usual way of driving steppers quickly with an ATMega or other 8-bit microcontroller is abusing the hardware timers. It’s quick, but there is a downside. It takes time for these timers to start and stop, and if you’re doing it two hundred times per second with four stepper motors, that clock jitter will ruin your CNC machine. The solution is to use a DMA channel to count down, with each count sending out a pulse to a stepper. It’s a clever abuse of the hardware, and the only drawback is the micro can’t send more than 2¹⁶ pulses per any 5ms period. That’s not really an issue because that would mean some very, very fast acceleration.

The Buildbotics team currently has a Kickstarter running for their four-axis CNC controller using this technique. It’s designed for Taig mills, 6040 routers, K40 lasers, and other various homebrew robots. It’s an interesting solution to the apparent end of the of the age of 8-bit microcontrollers in CNC machines and certainly worth checking out.