Hackaday Prize Entry: Density Altitude Gauge

Despite what extraordinarily overpowered quadcopters suggest, the air pressure of whatever a flying machine flys at is extremely important. Pressure is dependent on altitude and temperature, and there are hundreds of NTSB investigations that have concluded density altitude – pressure altitude corrected for nonstandard temperature variations – was the reason for a crash. Normally density altitude is computed through a slide rule or a flight computer, with the pilot entering in altitude and temperature, but somehow accidents still happen. For his entry to The Hackaday Prize, [Neil McNeight] is building an automated density altitude calculator to automate the process entirely.

Instead of having a pilot enter the altitude and temperature into a flight computer manually, [Neil]’s device grabs the current altitude from a GPS unit, and reads the temperature with a tiny sensor acquired from SparkFun. With just a little bit of math, this device will spit out the altitude an airplane or ‘copter thinks it’s at.

While the FAA won’t allow instruments that are cobbled together on a breadboard, this does have a few applications in the RC world. There are extremely high performance racing quadcopters out there now, and knowing how the craft will perform before flying it will save a few props.


The 2015 Hackaday Prize is sponsored by:

An Introduction To Valve’s Tracking Hardware

[Alan Yates] brought a demo of Valve’s new VR tech that’s the basis of the HTC Vive system to Maker Faire this year. It’s exceptionally clever, and compared to existing VR headsets it’s probably one of the best headtracking solutions out there.

With VR headsets, the problem isn’t putting two displays in front of the user’s eyes. The problem is determining where the user is looking quickly and accurately. IMUs and image processing techniques can be used with varying degrees of success, but to do it right, it needs to be really fast and really cheap.

[Alan] and [Valve]’s ‘Lighthouse’ tracking unit does this by placing a dozen or so IR photodiodes on the headset itself. On the tracking base station, IR lasers scan in the X and Y axes. By scanning these IR lasers across the VR headset, the angle of the headset to the base station can be computed in just a few cycles of a microcontroller. For a bunch of one cent photodiodes, absolute angles and the orientation to a base station can be determined very easily, something that has some pretty incredible applications for everything from VR to robotics.

Remember all of the position tracking hacks that came out as a result of the Nintendo Wii using IR beacons and a tracking camera? This seems like an evolutionary leap forward but in the same realm and can’t wait to see people hacking on this tech!

Tin Spider Is 13-foot Rideable Strandbeest

Arguably our best find at Bay Area Maker Faire this year was the Tin Spider built by [Scott Parenteau]. He constructed the 13-foot tall vehicle to take with him on his very first trip to Burning Man back in 2012. There’s very little information available online so we were excited that [Scott] spent some time speaking with us on Saturday.

Continue reading “Tin Spider Is 13-foot Rideable Strandbeest”

Vintage Microammeter Now Tells Temperature

[Craig] sent in this tip about a simple hack he built to convert an old analog micro-ammeter into a thermometer using a few parts. There’s a certain charm to retro analog meters, and there was enough space inside the old meter to accommodate the tiny breadboarded circuit and the three AA batteries to convert it into a cool looking centerpiece which is useful too!

He used the 3-pin MCP9700 analog temperature sensor connected to a LTC1541 – a combined comparator, op-amp and band gap reference voltage all rolled into one package. The thermometer displays 1uA per degree Celsius, has an output of 1mV per degree Celsius for external temperature monitoring / data logging, and draws just about 20uA. While the build itself is pretty simple, [Craig] took the time to walk through every design decision he made in the video after the break. This starts with the design for his circuit, and  moves on to the selection of parts and their values. The video is a must-watch for anyone wanting to learn more about precision op-amp based designs.

The three batteries will drain over time, and a circuit like this one requires a stable reference voltage. That is taken care by the bandgap reference voltage from the LTC1541. This eliminates the use of additional voltage regulators, and allows the circuit to work from 4.5V down to about 3.3V. Check the video after the break to listen to [Craig] describe how it works. We’re not sure how quickly it responds to changes in ambient temperature since the sensor is enclosed inside the meter, so maybe some vents at the back, or bringing out the sensor might be a good idea.

Continue reading “Vintage Microammeter Now Tells Temperature”

Ask Hackaday: The Internet Of Things And The Coming Age Of Big Data

Samsung has thrown its hat into the Internet of Things ring with its ARTIK platform. Consisting of three boards, each possesses a capability proportional to their size. The smallest comes in at just 12x12mm, but still packs a dual core processor running at 250MHz on top of 5 MB flash with bluetooth.  The largest is 29x39mm and sports a 1.3GHz ARM, 18 gigs of memory and an array of connectivity. The ARTIK platform is advertised to be completely compatible with the Arduino platform.

Each of these little IoT boards is also equipped with Samsung’s Secure Element. Worthy of an article on its own, this crypto hardware appears to be built into the processor, and supports several standards. If you dig deep enough, you’ll find the preliminary datasheet (PDF) to each of these boards. It is this Secure Element thing that separates the ARTIK platform from the numerous other IoT devices that have crossed our memory banks, and brings forth an interesting question. With the age of the Internet of Things upon us, how do we manage all of that data while keeping it secure and private?

What is The Internet of Things?

These kind of terms get thrown around too much. It was just the other day I was watching television and heard someone talk about ‘hacking’ their dinner. Really? Wiki defines the IoT as –

“a network of physical objects or “things” embedded with electronics, software, sensors and connectivity to enable it to achieve greater value and service by exchanging data with the manufacturer, operator and/or other connected devices.”

Let’s paint a realistic picture of this. Imagine your toaster, shower head, car and TV were equipped with little IoT boards, each of which connects to your personal network. You walk downstairs, put the toast in the toaster, and turn on the TV to catch the morning traffic. A little window pops up and tells you the temperature outside, and asks if you want it to start your car and turn on the air conditioning. You select “yes”, but not before you get a text message saying your toast is ready. Meanwhile, your daughter is complaining the shower stopped working, making you remind her that you’ve programmed it to use only so much water per shower, and that there is a current clean water crisis in the country.

This is the future we all have to look forward to. A future that we will make. Why? Because we can. But this future with its technical advancements does not come without problems. We’ve already seen how malicious hackers can interfere with these IoT devices in not so friendly ways.

Is it possible for our neighbor’s teenage kid to hack into our shower head? Could she turn our toaster on when we’re not home? Or even start our car? Let’s take this even further – could the government monitor the amount of time you spend in the shower? The amount of energy your toaster uses? The amount of time you let your car idle?

Clearly, the coming age of the Internet of Things doesn’t look as nice when we lose the rose colored glasses. The question is how do we shape our future connected lives in a way that is secure and private? If closed source companies like Samsung get their IoT technology into our everyday household items, would you bet a pallet of Raspberry Pi’s that the government will mine them for data?

This, however, does not have to happen. This future is ours. We made it. We know how it works – down to the ones and zeros. There is no fate, except that which we make. Can we make the coming IoT revolution open source? Because if we can, our community will be able to help ensure safety and privacy and keep our personal data out of the government’s hands. If we cannot, and the closed source side of things wins, we’ll have no choice but to dig in and weed out the vulnerabilities the hard way. So keep your soldering irons sharp and your bus pirates calibrated. There’s a war brewing.

Vintage Lens On A Modern Camera

Sometimes you get plain lucky in multiple ways, enabling you to complete a hack that would otherwise have seemed improbable. [Mario Nagano] managed to attach a vintage 1950’s lens to a modern mirrorless camera (translated from Portuguese).

Photographers tend to collect a lot of gear and [Mario] is no exception. At a local fair in Sao Paolo, he managed to pick up a Voigtlander Bessa I – a bellows camera (or folding camera). It came cheap, and the seller warned him as much, commenting on the bad external shape it was in. But [Mario] had a sharp eye, and noticed that this was a camera that would have remained closed most of the time, due to its construction.

Inspection showed that the bellows was intact. What excited and surprised him was the excellent Color-Skopar objective mounted on a Prontor-S trigger, which is considered premium compared to the entry level Vaskar lens. His plan was to pick up another Voigtlander Bessa-I with a better preserved body, but the cheaper lens and do a simple swap. He never did find another replacement though. Instead, he decided to fix the excellent vintage lens to a DSLR body.

He’d read about a few other similar hacks, but they all involved a lot of complicated adapters which was beyond his skills. Removing the lens from the vintage camera was straightforward. It was held to the body by a simple threaded ring nut and could not only be removed easily, but the operation was reversible and didn’t cause any damage to the old camera body. The vintage lens has a 31.5mm mounting thread while his Olympus DSLR body had a standard 42mm thread. Fabricating a custom adapter from scratch would have cost him a lot in terms of time and money. That’s when he got lucky again. He had recently purchased a Fotodiox Spotmatic camera body cap. It’s made of aluminium and just needed a hole bored through its center to match the vintage lens. There’s no dearth of machine shops in Sao Paolo and it took him a few bucks to get it accurately machined. The new adapter could now be easily fixed to the old lens using the original 31.5mm ring nut.

The lens has a 105mm focal length, so the final assembly must ensure that this distance is maintained. And he got lucky once again. He managed to dig up a VEB Pentacom M42 macro bellows from an old damaged camera. Was it worth all the effort ? Take a look at these pictures here, here and here.

Adafruit And The Arduinos At Maker Faire

The apparent lull on the Arduino front the last few weeks was just the calm before the storm that is the Bay Area Maker Faire (BAMF). Both companies claiming the Arduino name were there over the weekend, with news and new products in tow. Ironically, you could see from one booth straight over to the other. Small world.

Perhaps the biggest news from Arduino LLC is that hacker-friendly Adafruit is now going to be making officially-licensed boards in the US. Competing with this news, Arduino SRL brought its new boards, including the Yun Mini and ARM-powered Arduino M0. And [Massimo Banzi] and Arduino LLC seem to be taking an end-run around the Arduino SRL trademark by announcing the “Genuino” brand for European production. For all the details, read on!

Continue reading “Adafruit And The Arduinos At Maker Faire”