Martian Dust Storm May Spell Doom For Rover

August 28, 2018 by Tom Nardi 65 Comments

Everyone knows that space is an incredibly inhospitable place, but the surface of Mars isn’t a whole lot better. It’s a dim, cold, and dry world, with a wisp of an atmosphere that provides less than 1% of Earth’s barometric pressure. As the planet’s core no longer provides it with a magnetosphere, cosmic rays and intense solar flares bathe the surface in radiation. Human life on the surface without adequate environmental shielding is impossible, and as NASA’s fleet of rovers can attest, robotic visitors to the planet aren’t completely immune to the planet’s challenges.

As a planet-wide dust storm finally begins to settle, NASA is desperately trying to find out if the Red Planet has claimed yet another victim. The agency hasn’t heard from the Opportunity rover, which landed on Mars in 2004, since before the storm started on June 10th; and with each passing day the chances of reestablishing contact are diminished. While they haven’t completely given up hope, there’s no question this is the greatest threat the go-kart sized rover has faced in the nearly 15 years it has spent on the surface.

Opportunity was designed with several autonomous fail-safe systems that should have activated during the storm, protecting the rover as much as possible. But even with these systems in place, its twin Spirit succumbed to similar conditions in 2010. Will Opportunity make it through this latest challenge? Or has this global weather event brought the long-running mission to a dramatic close?

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PiPod: A Raspberry Pi Zero Portable Music Player

August 28, 2018 by Ben James 16 Comments

[Bram] wasn’t satisfied with the portable music playback devices that were currently available. He craved an offline music player that had a large storage capacity but found that this was only available in high-end, off-the-shelf options, which were far too expensive. [Bram] decided to make his own, powered by a Raspberry Pi zero. After building an initial prototype, the design was iterated a few times, with the latest version featuring a BOM cost of roughly €80.

The whole project is open source, with hardware and software files available on the project GitHub. A 2.2″ TFT displays the UI, which is of course completely customisable. Everything is squashed into a 3D printed case, which has the smallest form factor possible whilst retaining a decent amount of battery life. The electronics are what you’d expect: a boost converter to produce 5 V for the Pi from the 3.7V battery, a charge controller and a battery protection circuit. As a bonus, the battery voltage is monitored with a 12-bit ADC which reports to the Pi, enabling it to do a safe shutdown at low voltage, and display battery level on the UI.

Since the whole purpose of the device is to play audio, onboard filtered PWM wasn’t going to cut it, so instead a 24-bit DAC talks to the Pi via I2S. The audio player backend is VLC, so there’s support for plenty of different file types. A disc image of the whole system is available with everything pre-configured, and you can even buy the assembled PCB from Tindie.

Want to keep the look and feel of your old iPod? We covered an impressive restoration of a 6th gen model, upgrading the storage and battery significantly.

Where’s The Cat? Locating Your Moggy Without Eating Batteries

August 28, 2018 by Jenny List 38 Comments

Where the Hackaday Cat goes when she steps over the threshold into the wider world is a mystery, she reveals her whereabouts strictly on her terms and would we suspect be very cagey were we able to ask her about it. [Andy C] however has a need to know where his cat is spending her time, so he’s made a GPS collar for a bit of feline spying.

There are commercial GPS collars for pets, but they all share the flaw of extremely limited battery life. His challenge then was to create a collar that delivered the required pinpoint fix alongside a battery life measured in months. The solution was a combination of a low-power miniature GPS receiver and a low-power PC microcontroller hooked up to an FSK radio whose frequency he doesn’t give but which we suspect is probably the usual 433 MHz. The collar remains in low power mode until it receives a call on the FSK, at which point it wakes up, gets a GPS fix, transmits it, and returns to sleep.

The summary links to a series of posts which provide an extremely detailed look at all aspects of the project, and go well beyond mere GPS trackers for a cat. If you have an interest in low power devices or antenna matching for example, you’ll find a lot of interesting stuff in these pages. Of course, if all you need is a GPS tracker though, you may prefer a simpler option.