Radio MDZhB

If you have a shortwave receiver, tune it to 4625 kHz. You’ll hear something that on the surface sounds strange, but the reality is even stranger still. According to the BBC, the radio station broadcasts from two locations inside Russia — and has since 1982 — but no one claims ownership of the station, known as MDZhB. According to the BBC:

[For 35 years, MDZhB] has been broadcasting a dull, monotonous tone. Every few seconds it’s joined by a second sound, like some ghostly ship sounding its foghorn. Then the drone continues.
Once or twice a week, a man or woman will read out some words in Russian, such as “dinghy” or “farming specialist”. And that’s it.

If you don’t have a shortwave handy, you can always try one of the many web-based software defined radios. Search for 4.6 MHz, and pick a location that should have propagation to Russia and you are all set.

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Manually-Adjustable Three-Axis Gimbal

[Tim Good] built a 3-axis gimbal out of 3D-printed and machined pieces, and the resulting design is pretty sweet, with a nice black-on-black look. He machined the flat pieces because they were too long to be printed in his 3D-printer.

The various axes swivel on four bearings each, and each ring features a manual locking mechanism made out of steel stainless pins that immobilize each axis. The gimbal operation itself appears to be manual. That said, [Tim] used 12-wire slip rings to power whatever camera gets mounted on it–it looks like the central enclosure could hold a camera the size of a GoPro.

[Tim] has shared his design files on Thingiverse: it’s a complicated build with 23 different files. This complexity got us wondering: aren’t there two pitch axes?

We definitely love seeing gimbal projects here on Hackaday. A few cases in point, a gimbal-mounted quadcopter, another project with a LIDAR added to a camera gimbal, and this gimbal-mounted coffee cup.



Simple Step-Climbing Robot Climbs Like It’s On Mars

[Navin Khambhala] is a master at making simple what most would expect to be a complex build. Now he’s done it again with a remote controlled robot that can easily climb steps and role over rough terrain. The parts count is small and many of them are commonly available.

The suspension that makes it all possible is the rocker-bogie. It’s the same suspension we’ve all seen used by the various rovers ambling around on Mars. The whole frame is made of PVC pipes with some connecting metal bars, and each wheel has its own twelve-volt DC motor. Motor control is done simply with a module that combines the 2.4 GHz receiver with motor controllers. When you watch the video below, note where only one hole is drilled through the PVC for making connections instead of two holes. Where there’s only one hole, the two sections of PVC are free to rotate independently of each other. Turning the robot is done by rotating the wheels on one side in one direction and the wheels on the other side in the opposite direction. This is called a differential drive or tank drive, and we’ve highlighted it before for use in making hamster-drive type BB-8 droids.

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Hackaday Prize Best Product Finalist: Reconfigurable Robots

Reconfigurable robots have been around for ages. One of the first and most popular reconfigurable robots came out of the MIT Media Lab, and last year, DTTO, a modular snake-like robot, won the 2016 Hackaday Prize. There’s a lot that can be learned from a robot that can turn from a walker to a swimmer to something that clambers over rough terrain, and [Salvador]’s EMME does just that. It’s a 3D printed robot and controller that’s the closest you can get to, ‘the Lego of robots’. All you need to do is plug some wheels into a controller and you’re off to the races.

[Salvador]’s EMME is a brilliant little robot that’s only made of a few generic parts. These parts snap together or join with magnets to turn into any device you can imagine that somehow turns rotation of a wheel into linear motion. All the parts are 3D printed, work without cables or connectors, and the robot itself is controlled by a wireless gem-shaped 3D printed controller.

Already, [Salvador] has on-road wheels for EMME, off-road wheels, above-water wheels, and submersible accessories. This is already an all-terrain robot that’s easy to put together and easy to control, but [Salvador] isn’t done yet. he’s working on new hardware based on the ESP32 and working on the vast amount of documentation required for a robot that can do anything.

You can check out [Salvador]’s pitch video for EMME below.

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Wooden Domino Laying Machine

[Matthias Wandel]  has come up with another awesome machine, this time a machine that sets up neat rows of dominos. If you’ve followed [Matthias]’s work over the years then you’ll know that this is a wooden version of one he made out of LEGO® back in 2009.

In true [Matthias] fashion he uses just the one motor both for moving the machine along and for pushing the dominos in place. Not satisfied with that efficient use of parts, the rubber band belts that transfer rotation from the motor shaft to the wheels (bearings) double as the rubber surfaces for those wheels. One of many joys from watching [Matthias] work is seeing how he forms wood into shapes that most people would have trouble sculpting from clay. In this case he does this when he needs parts for reaching over his domino magazine to hold a guide rail in place, and of course the parts are well-rounded and clean-looking.

You might also ask, where did he get all the wooden blocks for dominos? He made them of course, all 300 or so.

Be sure to check out the video below of both the build, and of it in action.

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FLEX Pager Protocol in Depth

We love pager hacks. One of our earliest head-slappers was completely reverse-engineering a restaurant pager’s protocol, only to find out that it was industry-standard POCSAG. Doh!

[Corn] apparently scratches the same itch, but in the Netherlands where the FLEX protocol is more common. In addition to walking us through all of the details of the FLEX system, he bought a FLEX pager, gutted it, and soldered on an ATMega328 board and an ESP8266. The former does the FLEX decoding, and the latter posts whatever it hears on his local network.

These days, we’re sure that you could do the same thing with a Raspberry Pi and SDR, but we love the old-school approach of buying a pager and tapping into its signals. And it makes a better stand-alone device with a lot lower power budget. If you find yourself in possession of some old POCSAG pagers, you should check out [Corn]’s previous work: an OpenWRT router that sends pages.

3DP Enigma Keyboard Improves on the Original

[Asciimation], who previously created an Enigma Machine wristwatch, decided to go all-in and make a 3D-printed Enigma machine. Not a perfect replica, but rather an improved version that works the same but doesn’t concern itself with historical accuracy. For instance, the current step involves building the keyboard. Rather than trying to re-create the spring-and-pin method of the original, he simply swapped in readily available, double-throw micro switches.

This project has a tremendous amount of fascinating detail. [Asciimation] did his research and it shows; he downloaded blueprints of the original and used hacked digital calipers to precisely measure each rotor’s teeth, so that it could be re-created for printing. He even re-created the Enigma font to ensure that his printed rotor wheels would look right–though in doing so he discovered that the original machine used one typeface for the keyboard, one for the wheels, and one for the indicator lamps.

We previously published [Asciimation]’s Enigma machine wristwatch project, where he simulated the functionality of an Enigma with an Arduino.

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