Make Munich Was Awesome

It was a good weekend to be geeky in Bavaria. In addition to our own Hackaday Prize Bring-a-Hack party, there was the reason that we scheduled it in the first place, Munich’s independent DIY expo, Make Munich.

If you’re a loyal Hackaday reader, many of the projects would seem uncannily familiar. I walked in and was greeted by some beautiful word clocks in both German and English, for instance. Still, seeing the Open Theremin being sold with an “as seen on Hackaday” sticker made us smile. And then we had a great conversation about [Urs Gaudenz]’s other project: DIY biological apparatus, also seen on Hackaday.

There were robots galore. Someone (from Gmünd?) was driving around a graffiti-bot and spraying the floor with water instead of paint or chalk to very nice effect. The full evolution of the Zoobotics robot family was on display. Even the Calliope (a German version of the micro:bit) booth had this cute Bluetooth vibrobot. Join me after the break as I dive into all of the great stuff on display over the weekend.

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DIY Lap Counters For Drone Racing

Drone racing is a very exciting sport, in which there is a lot of room for hackers and makers to add that special sauce into the mix. Usually the aerial finish line requires special race-timing hardware to do the lap counting, and there are timing gate transponders available for around $40. In his project CoreIR and CoreIR-Uplink, [Michael Rickert] decided to reverse engineer the IR Protocol that goes into these beacons and made a homebrew version that mimics the original. The transponders send a 7-digit number out repeatedly to a receiver at the finish line as the UAV passes by and that helps track how fast drone pilots flew around a race track. The hack involves flipping an IR LED ON and OFF with the correct timing, and [Michael Rickert] confesses that it was not as easy as he had imagined.

Using a logic analyser he was able to capture the modulated 38Khz carrier signal and extract the timing from the original beacon, but it took a number of iterations to get the code just right. The IRRemote library has a ‘sendRaw’ function which is quite helpful in these situations and was employed for the task. He experimented with a number of Arduino boards to power the project, before finally going with the Arduino Pro Mini. He has shared the code on github, along with photos of the finished hack which replaces the original circuit. The final sketches include functions to generate the 7-digit code to uniquely identify the quadcopter, which completes the hack in itself.

If that was not enough, he’s gone a step further by coding and sharing a desktop client as well, which turns this hack into a full-fledged project and should prove quite useful for drone racers on a budget. The app is written in NodeJS and packaged using the electron framework, a choice that makes for a very simple way to create cross-platform desktop applications.

A build tutorial is available for you to get started, and if drone racing seems a bit tame, check out Drone Wars for a little more carnage.

VR Mech’s Missing Link: The Phone In Your Pocket

In the process of making a homemade Mech Combat game that features robot-like piloted tanks capable of turning the cockpit independent of the direction of movement, [Florian] realized that while the concept was intuitive to humans, implementing it in a VR game had challenges. In short, when the body perceives movement but doesn’t feel the expected acceleration and momentum, motion sickness can result. A cockpit view that changes independently of forward motion exacerbates the issue.

To address this, [Florian] wanted to use a swivel chair to represent turning the Mech’s “hips”. This would control direction of travel and help provide important physical feedback. He was considering a hardware encoder for the chair when he realized he already had one in his pocket: his iPhone.

By making an HTML page that accesses the smartphone’s Orientation API, no app install was needed to send the phone’s orientation to his game via a WebSocket in Unity. He physically swivels his chair to steer and is free to look around using the VR headset, separate from the direction of travel. Want to try it for yourself? Get it from [Florian]’s GitHub repository.

A video is embedded below, but if you’re interested in details be sure to also check out [Florian]’s summary of insights and methods for avoiding motion sickness in a VR Mech cockpit.

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Lens Mount

X-Ray Imaging Camera Lens Persuaded To Join Micro Four Thirds Camera

Anyone who is into photography knows that the lenses are the most expensive part in the bag. The larger the aperture or f-stop of the lens, the more light is coming in which is better for dimly lit scenes. Consequently, the price of the larger glass can burn a hole in one’s pocket. [Anthony Kouttron] decided that he could use a Rodenstock TV-Heligon lens he found online and adapt it for his micro four-third’s camera.

The lens came attached to a Fischer Imaging TV camera which was supposedly part of the Fluorotron line of systems used for X-ray imaging. We find [Anthony’s] exploration of the equipment, and discovery of previous hacks by unknown owners, to be entertaining. Even before he begins machining the parts for his own purposes, this is an epic teardown he’s published.

Since the lens was originally mounted on a brass part, [Anthony Kouttron] knew that it would be rather easy to machine the custom part to fit standardized lens adapters. He describes in detail the process for cleaning out the original mount by sanding, machining and threading it. Along the way you’ll enjoy his tips on dealing with a part that, instead of being a perfect circle on the outside, had a formidable mounting tab (which he no longer needed) protruding from one side.

The video after the break shows the result of shooting with a very shallow depth of field. For those who already have a manual lens but lack the autofocus motor, a conversion hack works like a charm as well.

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E-ink Display Driven DIY

E-ink displays are awesome. Humans spent centuries reading non-backlit devices, and frankly it’s a lot easier on the eyes. But have you looked into driving one of these critters yourself? It’s a nightmare. So chapeau! to [Julien] for his FPGA-based implementation that not only uses our favorite open-source FPGA toolchain, and serves as an open reference implementation for anyone else who’s interested.

Getting just black and white on an E-ink display is relatively easy — just hit the ink pixels with the same signal over and over until they give up. Greyscale is made by applying much more nuanced voltages because the pixels are somewhat state-dependent. If the desired endpoint is a 50% grey, for instance, you’d hit it with a different pulse train if the pixel were now white versus if it were now black. (Ever notice that your e-book screen periodically does a white-black flash? It’s resetting all the pixels to a known state.) And that’s not even taking into account the hassles with the various crazy voltages that E-ink displays require, which [Julien] wisely handed off to a dedicated chip.

In the end, the device has to make 20-50 passes through the screen for one user-visible refresh. [Julien] found that the usual microcontrollers just weren’t capable of the speed that he wanted, hence the FPGA and custom waveform tables. We’ve seen E-ink hacks before, and [Julien] is standing on the shoulders of giants, most notably those of [Petteri Aimonen] and [Sprite_tm]. [Julien]’s hack has the fastest updates we’ve ever seen.

We still can’t wait for the day that there is a general-purpose E-ink driver chip out there for pennies, because nearly every project we make with a backlit display would look better, and chew through the batteries slower, with E-ink. In the meantime, [Julien]’s FPGA implementation is pretty close, and it’s fully open.

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Making Metal Dominoes

Nearly as versatile as a deck of playing cards, dominoes are a great addition to any rainy-day repertoire of game sets. [Apollo] from the Youtube channel [carbide3d] has manufactured for themselves a custom set of domino tiles replete with brass pips.

Cutting the bar stock to the appropriate size, [Apollo] ran a few test engravings and hole sizes for the brass pips. That done, all they had to do was repeat the engraving and milling process another couple dozen times, as well as all the requisite wet and dry sanding, and buffing. [Apollo] opted to use paint marker to add a little extra style to the tiles, and advises any other makers who want to do the same to set their engraving depth to .01″ so  the paint marker won’t be rubbed off when buffing the pieces.

When it came to installing the brass balls, [Apollo] undersized the holes by .001″-.002″ for a snug press fit — adding that the hole depth is a little greater than half the ball’s diameter. They used 1/8″ balls for the pips, and 3/16 balls for the center of the tiles which also allows the tiles to be spun for a bit of fidgeting fun during play. Check out the build video after the break.

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Cordless Water Pump!

A water pump is one of those items that are uncommonly used, but invaluable when needed. Rarer still are cordless versions that can be deployed at speed. Enter [DIY King 00], who has shared his build of a cordless water pump!

The pump uses an 18 volt brushed motor and is powered by an AEG 18V LiPo battery. That’s the same battery as the rest of [DIY King]’s power tools, making it convenient to use. UPVC pipe was used for the impeller — with a pipe end cap for a housing. A window of plexiglass to view the pump in motion adds a nice touch.

A bit of woodworking resulted in the mount for the pump and battery pack, while a notch on the underside allows the battery to lock into place. Some simple alligator clips on the battery contacts and the motor connected through a switch are all one needs to get this thing running.

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