A Beacon Suitable For Tracking Santa’s Sleigh?

December 19, 2016 by Anool Mahidharia 8 Comments

High-altitude ballooning is becoming a popular activity for many universities, schools and hacker spaces. The balloons, which can climb up to 40 km in the stratosphere, usually have recovery parachutes to help get the payload, with its precious data, back to solid ground safely. But when you live in areas where the balloon is likely to be flying over the sea most of the time, recovery of the payload becomes tricky business. [Paul Clark] and his team from Durham University’s Centre for Advanced Instrumentation are working on building a small, autonomous glider – essentially a flying hard drive – to navigate from 30 km up in the stratosphere to a drop zone somewhere near a major road. An important element of such a system is the locator beacon to help find it. They have now shared their design for an “Iridium 9603 Beacon” — a small Arduino-compatible unit which can transmit its location and other data from anywhere via the Iridium satellite network.

The beacon uses the Short Burst Data service which sends email to a designated mail box with its date, time, location, altitude, speed, heading, temperature, pressure and battery voltage. To do all of this, it incorporates a SAMD21G18 M0 processor; FGPMMOPA6H GPS module; MPL3115A2 altitude sensor; Iridium 9603 Short Burst Data module + antenna and an LTC3225 supercapacitor charger. Including the batteries and antenna, the whole thing weighs in at 72.6 g, making it perfectly suited for high altitude ballooning. The whole package is powered by three ‘AAA’ Energizer Ultimate Lithium batteries which ought to be able to withstand the -56° C encountered during the flight. The supercapacitors are required to provide the high current needed when the beacon transmits data.

The team have tested individual components up to 35 km on a balloon flight from NASA’s Columbia Scientific Balloon Facility and the first production unit will be flown on a much smaller balloon, launched from the UK around Christmas. The GitHub repository contains detailed information about the project along with the EagleCAD hardware files and the Arduino code. Now, if only Santa carried this on his Sleigh, it would be easy for NORAD to track his progress in real time.

A DIY Net Gun To Catch Whatever You Want

December 19, 2016 by James Hobson 21 Comments

Suspicious drones hovering about your property? Burglars or other ne’er-do-well test subjects giving you trouble? Need to catch a dog that keeps meandering through your workshop? [William Osman] suggests you build yourself a pneumatic net gun that can shoot 20-30 feet to catch them all.

The net gun is built largely out of PVC pipe; the air tank — filled via a tire valve — uses adapter fittings to shrink it down to a 1″ sprinkler valve, with an air gun to act as a trigger. The net launcher is made of four lengths of pipe bent with the use of a heat gun — an Occam’s Razor solution compared to his first attempt — and is coupled to the end, while the net loads in using wooden dowels with washers as weights. It won’t trap any large game, but it will certainly net you some fun.

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Portable Apple II On An AVR

December 19, 2016 by Rich Hawkes 36 Comments

The Apple II was one of the first home computers. Designed by Steve “Woz” Wozniak, it used the MOS technologies 6502 processor, an 8-bit processor running at about 1 MHz. [Maxstaunch] wrote his bachelor thesis about emulating the 6502 in software on an AVR1284 and came up with a handheld prototype Apple II with screen and keyboard.

Originally, [maxstrauch] wanted to build an NES, which uses the same 6502 processor, but he calculated the NES’s Picture Processing Unit would be too complicated for the AVR, so he started on emulating the Apple II instead. It’s not quite there – it can only reference 12K of memory instead of the 64K on the original, so hi-res graphic mode, and therefore, many games, won’t work, but lo-res mode works as well as BASIC (both Integer BASIC and Applesoft BASIC.)

[Maxstrauch] details the 6502 in his thesis and, in a separate document, he gives an overview of the project. A third document has the schematic he used to build his emulator. His thesis goes into great detail about the 6502 and how he maps it to the AVR microcontroller. The build itself is pretty impressive, too. Done on veroboard, the build has a display, keyboard and a small speaker as well as a micro SD card for reading and storing data. For more 6502 projects, check out the Dis-Integrated 6502 and also, this guide to building a homebrew 6502.

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Samy Kamkar Illustrates How To Be A Hardware Hacker

December 19, 2016 by Mike Szczys 4 Comments

Samy Kamkar is well known for many things, but lately it has been his hardware security hacks that have been turning heads. The nice thing to know is that, despite not having a background in hardware, Samy is able to run with the best of hardware researchers. At the Hackaday SuperConference he offered words of advice for anyone trying to walk the path of discovery with an exciting new piece of electronics. One might say it’s a crash-course in how to be a hardware hacker.

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How Has Amazon Managed To Make Hackers Love Alexa?

December 19, 2016 by Jenny List 114 Comments

Our hackspace has acquired an Amazon Dot, courtesy of a member. It mostly seems to be used as a source of background music, but it has also spawned a seemingly never-ending new entertainment in which the hackspace denizens ceaselessly bait their new electronic companion with ever more complex and esoteric requests. From endless rephrasing and careful enunciation of obscure early reggae artists to try to settle a musical argument to hilarious mis-hearing on the part of our silicon friend, the fun never stops. “Alexa, **** off!” it seems results in “I’m sorry, I can’t find a device of that name on this network”.

That is just the experience of one hackspace, but it evidently does not end there. Every other day it seems that new projects using Alexa pass through the Hackaday timeline, so it looks as though Amazon’s online personal assistant has been something of a hit within our community.

Fair enough, you might say, we’re always early adopters of any new technology. But it’s a development over which I wonder; am I alone in finding it surprising? It’s worth taking a moment to look at the subject.

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Password-Free Guest WiFi From Raspberry Pi

December 19, 2016 by Bryan Cockfield 31 Comments

Anytime you’re having more than a handful of people over to your place for a wild rager or LAN party (or both), you’ll generally need a way to make sure everyone can get their devices on the network. Normally, this would involve either putting your WiFi password into more phones than you can count or yelling your password across a crowded room. Neither of these options suited [NicoHood] and his partner, however, so he came up with another more secure solution to the WiFi-in-a-crowded-room problem.

He calls his project “guestwlan” and it’s set up to run on a Raspberry Pi with a touch screen. When a potential WiFi user approaches the Pi and requests access to the network, the Pi displays a QR code. Within that code is all of the information that the prospective device needs to connect to the network. For those who have already spotted the new security vulnerability that this creates, [NicoHood] has his guest WiFi on a separate local network just to make sure that even if someone nefarious can access the Internet, it would be more difficult for them to do anything damaging to his local network. As it stands, though, it’s a lot more secure than some other WiFi networks we’ve seen.

[NicoHood] also released his software on Git but it has been configured for use with Arch. He says that it would probably work in a Debian environment (which the Raspberry Pi-specific OS is based on) but this is currently untested. Feel free to give it a try and let us know how it goes.

Closing The Loop On An Artificial Pancreas

December 19, 2016 by Dan Maloney 43 Comments

Life as a parent is never easy, but when you’ve got a kid with Type 1 diabetes it’s a little harder. Sometimes it feels like a full-time job in itself; there’s never a break. With carb counts and insulin ratios that change throughout the day, every meal is a medical procedure. A romp in the snow or a long bike ride can send her blood glucose plummeting. The overnights are the worst, though, because you never know if you overestimated the number of carbs at dinner and gave her too much insulin. Low blood glucose is easily treated with a few sips of juice, but if it goes unnoticed in the middle of the night, it could be fatal. That’s why parents of diabetics are always a little glassy eyed — we rarely sleep.

Why is all this necessary? It’s because Type 1 diabetes (T1D) is an autoimmune disease that attacks the insulin-producing beta cells in the pancreas. Once those cells are dead, insulin is no longer produced, and without insulin the rest of the cells in the body can’t take in the glucose that they need to live. Diabetics have to inject just the right amount of insulin at just the right time to coincide with the blood glucose spike that occurs after meals. Knowing how much to give and when is why we say we have to “learn to think like a pancreas.”

1-1-2-4_ping — Animas Ping insulin pump, partial teardown. The cylinder on the bottom is the battery, the motor and syringe compartment are on top. Source: Animas

Things are better than they used to be, for sure. Insulin pumps have been a game changer for T1Ds. An insulin pump is just a tiny syringe pump. A small motor moves the plunger on a disposable syringe filled with a few days worth of insulin. The hormone is delivered through a small catheter placed under the skin every few days — painful, but better than a needle stick with every meal and snack. A computer keeps track of everything and provides safety against overdosing on insulin, so it’s terribly convenient, but we still need to “think like a pancreas” and calculate the amount to deliver.

Even with its shortcomings, my daughter’s pump has been a blessing, and I’ll do whatever it takes to keep her in the latest gear. Pumps generally cost about $5000 or so, and need to be replaced every three years. While I’m not looking forward to paying the bill when her current pump gives up the ghost, I am certainly keen to do a teardown on the old one. I suspect it’s dead simple in there — a tiny gear motor, some kind of limit switches, and a main board. It’ll be painful to see how little my money buys, but it’ll be cool to play around with it.

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