Hackaday Links: September 29, 2019

In a sure sign that we’ve arrived in the future, news from off-world is more interesting this week than Earth news. When the InSight probe landed on Mars last year, it placed the first operating magnetometer on the Red Planet. Since then, the sensitive instrument has been logging data about the planet’s magnetic field, and now there are reports that researchers have discovered a chain of pulsations in the magnetic field. Pulsations in planetary magnetic fields aren’t all that strange; pulse trains that occur only at Martian midnight are, though. Researchers haven’t got a clue yet about what this means. We assume they’ve eliminated artifacts like something on the lander being turned on at local midnight, so when they figure it out it should be fascinating.

In more news from the future, Boston Dynamics is trolling us again. We covered the announcement early this week that they’re putting their Spot quadruped robot on sale – sort of. Turns out you need to be selected to qualify based on the application you have in mind, plus have several Ferraris full of cash to spend. While everyone was watching the adorable antics of Spot as it wandered through improbably industrial vignettes, Boston Dynamics also released this slightly terrifying video of their Atlas robot running through a gymnastics routine.  It starts with a headstand and a front roll and ends with a slipt leap and whatever the gymnastics equivalent of a figure skating axel jump is. Yes, it has a special roll cage attached to make the tumbles a bit smoother, but it’s still some remarkable stuff.

How are your RF design skills? If they’re good enough to design an RF power amp, you might want to check out this homebrew RF design challenge. Put on by NXP Semiconductors, the design must use one of their new LDMOS RF power transistors. They’ll send you samples so you can build your design, and you stand to win up to $3000 plus $1000 worth of NXP products. The contest opened back in May but is running through the middle of November, so you’d better hurry.

Speaking of RF, wouldn’t it be interesting to see a snapshot of the RF spectrum over the entire planet? ElectroSense thinks so, and they’re working on a crowdsourcing model to set up a globe-spanning network of connected RF sensors. The idea is similar to what FlightAware does for monitoring the locations of aircraft with a distributed network of ADS-B receivers. But where FlightAware only monitors a narrow slice of spectrum, ElectroSense wants it all – DC to 6 GHz. You can build a sensor from an SDR and a Raspberry Pi and start contributing to the effort, which only has a handful of sensors at the moment.

Has affordable metal 3D-printing finally arrived? For certain values of affordability, it soon will, when One Click Metal launches their new selective laser melting printer. Thomas Sanladerer did a video with the principals, and the prototype looks promising. SLM is not a new process, but patents on the core process recently ran out, so startups like One Click Metal are jumping into the market. Their printer won’t be cheap — you’ll still need to write a check with many zeroes — but with more players, the price should come down.

And finally, what’s this world coming to when a startup specializing in building giant fighting robots can’t make a go of it? MegaBots is shutting down, and while that’s certainly bad news for its founders and employees, it’s great news for anyone in the market for used battle bots. The company’s flagship bot, the 15-ton Eagle Prime, is currently up for auction on eBay. Bidding started at $1 with no reserve, but if you were looking for a steal, you’re a bit late. The high bid is currently $100,100, which is still an incredible buy considering it cost $2.5 million to build. You’ll have to pay for shipping, but you’ll have a super-destructive mecha of your own to drive around. And think how cool you’ll look rolling into some kid’s backyard birthday party. Presumably one you’ve been invited to.

Ask Hackaday: What Good Is A Robot Dog?

It is said that Benjamin Franklin, while watching the first manned flight of a hot air balloon by the Montgolfier brothers in Paris in 1783, responded when questioned as to the practical value of such a thing, “Of what practical use is a new-born baby?” Dr. Franklin certainly had a knack for getting to the heart of an issue.

Much the same can be said for Spot, the extremely videogenic dog-like robot that Boston Dynamics has been teasing for years. It appears that the wait for a production version of the robot is at least partially over, and that Spot (once known as Spot Mini) will soon be available for purchase by “select partners” who “have a compelling use case or a development team that [Boston Dynamics] believe can do something really interesting with the robot,” according to VP of business development Michael Perry.

The qualification of potential purchasers will certainly limit the pool of early adopters, as will the price tag, which is said to be as much as a new car – and a nice one. So it’s not likely that one will show up in a YouTube teardown video soon, so until the day that Dave Jones manages to find one in his magic Australian dumpster, we’ll have to entertain ourselves by trying to answer a simple question: Of what practical use is a robotic dog?

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Spot Welding …Plastic?

Plastic milk bottles, when your project or prototype needs an urgent source of plastic, they are often the first thing to hand. Convenient and flexible, but strong at the same time and usually free, they’re the ultimate source of material in a pinch. However, when it comes to actually manipulating the HDPE plastic they’re made from, there’s often a challenge. It’s easy to cut, but not so easy to join. Conventional glues can have a hard time, making it difficult to bond.

Enter [zimitt], and a spot welding solution for joining HDPE with ease. Ok, so ‘spot welding’ might be a little optimistic given the speed of this process, but it’s useful nonetheless. To heat the plastic, a cheap soldering iron is recommended. A low wattage, straight-to-the-wall one does well, especially as they commonly have the washer-style end shown in the picture. To protect the plastic from burning, a BBQ mat is used – they’re temperature resistant and usually made with a PTFE surface.

First, place the two sheets of plastic face to face and sandwich top and bottom with the BBQ mat. Apply some heat to the mat with the soldering iron then, after a few seconds, remove the iron and provide pressure with a flat object to bond the plastic. [zimitt] used an espresso tamper for this which was ideal.

The results are impressive, and [zimitt] experiments with different plastics as well. Of course, you should exercise caution when attempting anything like this, given the health risks present when heating up different types of plastic.

HDPE is easy to recycle at home, and we’ve seen a lot of great uses: a plastic joiner’s mallet, plastic tiles, and even a filament extruder for 3D printing.

SpotMini Struts Its Stuff

Boston Dynamics, the lauded robotics company famed for its ‘Big Dog’ robot and other machines which push mechanical dexterity to impressive limits have produced a smaller version of their ‘Spot’ robot dubbed ‘SpotMini’.

A lightweight at 55-65 lbs, this quiet, all-electric robot lasts 90 minutes on a full charge and boasts partial autonomy — notably in navigation thanks to proprioception sensors in the limbs. SpotMini’s most striking features are its sleek new profile and manipulator arm, showing off this huge upgrade by loading a glass into a dishwasher and taking out some recycling.

Robots are prone to failure, however, so it’s good to know that our future overlords are just as susceptible to slipping on banana peels as we humans are.

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Communicating From Anywhere With A SPOT Connect

[Nate] over at Sparkfun put up a great tutorial for using the SPOT personal satellite communicator with just about any microcontroller. These personal satellite transmitters were originally intended to pair with the bluetooth module of a smart phone, allowing you to send a short 41-character message from anywhere in the world. Now, you can use these neat little boxes for getting data from remote sensors, or even telemetry from a weather balloon.

[Nate]’s teardown expands on [natrium42/a>] and [Travis Goodspeed]’s efforts in reverse-engineering the SPOT satellite communicator. The hardware works with the Globalstar satellite constellation only for uplink use. That is, you can’t send stuff to a remote device with a SPOT. After poking around the circuitry of the original, first-edition SPOT, [Nate] pulled out a much cheaper SPOT Connect from his bag of tricks. Like the previous hacks, tying into the bluetooth TX/RX lines granted [Nate] full access to broadcast anything he wants to a satellite sitting in orbit.

We’ve seen the SPOT satellite messaging service put to use in a high altitude balloon over the wilds of northern California where it proved to be a very reliable, if expensive, means of data collection. Sometimes, though, XBees and terrestrial radio just aren’t good enough, and you need a satellite solution.

The SPOT satellite service has an enormous coverage area, seen in the title pic of this post. The only major landmasses not covered are eastern and southern Africa, India, and the southern tip of South America. If anyone out there wants to build a transatlantic UAV, SPOT, and [Nate]’s awesome tutorial, are the tools to use.

Tip ‘o the hat to [MS3FGX] for sending this one in.

Reverse Engineering Bluetooth Using Android And SPOT As An Example

[Travis Goodspeed] wrote in to tell us about his work reverse engineering the Bluetooth communications on this SPOT module. He’s targeted the post as a general guide to sniffing Bluetooth transmissions, but was inspired to use the SPOT as an example after seeing this other SPOT hack. We know he’s a fan of getting things to work with his Nokia N900, and that’s exactly where he ended up with the project.

This module was manufactured to be controlled by an Android phone. But there’s no control app available for the Nokia handset. Since Android uses the open-source Bluez package for the Bluetooth protocol, it’s actually pretty easy to get your hands on the packets. After grabbing a few test sets he shows how he deciphered the packets, then wrote a quick Python script to test out his findings. After working his way through the various commands available (grabbing the SPOT serial number, getting position data from it, etc) [Travis] wrote up a frontend in QT mobility for use on the N900.

Hacking SPOT Personal Satellite Tracker To Pass More Information

For less than $100 you can buy a little tracking module that will upload your location to a satellite. But you’ll only get latitude and longitude information. [Natrium42] spent some time reverse engineering the hardware, and the communications protocol, to allow custom data to be transferred using a SPOT module.

The flat fee for the hardware includes a one-year service plan allowing you to tack your device on the SPOT website. [Natrium42] started poking around in the transmitted data packages, and figured he could push custom messages like altitude data if he had some way to encode it as a valid latitude/longitude package. He found that location data is transmitted as two sets of three bytes each. The four least significant bits of each set get rounded by the server, leaving a total of 40 usable bits between the two data sets. He wrote encoding and decoding functions that will allow you to transfer whatever information you want.

So what is this good for? To get the process working he removed the MSP430 microcontroller from the board and is using his own replacement. So you can transmit GPS data from the onboard module, your own module, or sensor data for anything you’re able to hook up the to the replacement uC.