Word Tour Map of High Altitude Balloon Launched at Hackaday Supercon.

Supercon Balloon W6MRR-26 Continues Its World Tour

[Martin Rothfield] and other amateur radio operators from San Francisco High Altitude Ballooning (SF-HAB) treated conference attendees to the 2022 Hackaday Supercon to the launch of two High Altitude Balloons (HABs). On the morning of November 6th, the two balloons were launched from a park across the street from Supplyframe DesignLab in Pasadena, California.

Seven days after its launch from Southern California, one of the balloons was over Tajikistan cruising eastward at an altitude of 42,000 feet (12,800 meters). Balloon W6MRR-26 was already approaching China where it will continue its wonderful world tour to parts unknown. The second balloon (call sign W3HAC-11) landed in northern Arizona where it has continued transmitting whenever it receives power from the sun.

Each balloon carries a tiny payload — a printed circuit board powered only by small photovoltaic cells. The board includes a microcontroller, a GPS module, and a Weak Signal Propagation Reporter (WSPR) radio transmitter.  The transmitted operates on the 20 meter amateur radio band at around 14 MHz.

WSPR beacons can provide time, altitude, and location information.  The WSPR telemetry is then relayed via WSPRgates using Automatic Packet Reporting System (APRS) onto the Internet. The collected information can be viewed and mapped on websites such as aprs.fi.

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Pop Your Way To A Fresh Roast Coffee

The preparation and consumption of coffee has become something of an art from in our community, with many people going to extravagant lengths to achieve the perfect cup. [Eric Sorensen] was keen to roast his own beans, but given the price of a dedicated roaster, instead made his own using a hot air popcorn popper.

The story unfolds in several parts, and starts with disabling the thermal cutout on the popper to be replaced with thermal sensors. An Arduino controls both the fan and the heating coil to regulate and vary the roasting temperature over time. Perhaps it’s the software and user interface that most makes this project shine, with a graphical interface on a 320 by 240 pixel touch screen, and a graphing profile interface more reminiscent of a reflow oven than a kitchen appliance. The whole thing is neatly packed away with its power supply in a slimline case, and while we’re no bean experts, we appreciate the uniform brown of the finished product.

Coffee roasters have appeared here numerous times over the years. One of the more recent was this wobble disk design.

Building A LEGO Pneumatic Engine

Pneumatic engines aren’t something we use every day, but they’re compelling things to see working in practice. [Nico71] built an eye-catching example out of LEGO Technic, and it’s remarkably fully-featured.

The build relies on a single pneumatic cylinder driving a flywheel. Flow to the cylinder is determined by camshaft-controlled valves. The valves themselves are custom-built, composed of hose loops that are kinked to shut off flow. In addition to the basic operating components, the engine also features a throttle valve which uses the same kinked-hose principle. The main control valves are installed in a housing that can be rotated relative to the engine’s frame to vary the timing of the valves relative to the flywheel’s rotation. A gear system allows fine adjustment of the timing. The throttle and timing controls are accessible on a tidy control panel complete with a idle-adjust mechanism.

Those wishing to build one themselves can rejoice, for [Nico71] provides instructions for a small fee. We’ve seen other air engines before, too, often of the 3D-printed variety.

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Logic Via DNA

We often say you can make logic gates out of nearly anything. [Steve Mould] would agree as he just finished playing naughts and crosses (tic tac toe if you are an American) with a tray full of DNA. You can see the resulting game and how it works in the video below.

The use of DNA isn’t really significant as it simply implements a logic equation for each of the nine cells. So, for example, each cell is taken by an X (the DNA) only when certain other squares have been taken by O or not taken by O. So you essentially create an AND/OR gate using the state of each cell and its inverse.

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Hackaday supercon badge PCB showing illuminated activity lights after being loaded with a punch card

Supercon Badge Reads A “Punch” Card

This year’s Hackaday Supercon, the first since 2019 thanks to the pandemic, was a very similar affair to those of the past. Almost every hardware-orientated hacker event has its own custom electronic badge, and Supercon was no different. This year’s badge is a simulation platform for a hypothetical 4-bit CPU created by our own [Voja Antonic], and presented a real challenge for some of the attendees who had never touched machine code during their formative years. The challenge set was to come up with the most interesting hack for the badge, so collaborators [Ben Hencke] and [Zach Fredin] set about nailing the ‘expandr’ category of the competition with their optical punched card reader bolt-on.

Peripheral connectivity is somewhat limited. The idea was to build a bolt-on board with its own local processing — using a PixelBlaze board [Ben] brought along — to handle all the scanning details. Then, once the program on the card was read, dump the whole thing over to the badge CPU via its serial interface. Without access to theirPrinted paper faux punch card showing read LEDs and an array of set and reset bits of the encoding usual facilities back home, [Ben] and [Zach] obviously had to improvise with whatever they had with them, and whatever could be scrounged off other badges or other hardware lying around.

One big issue was that most people don’t usually carry photodiodes with them, but luckily they remembered that an LED can be used as a photodiode when reverse-biased appropriately. Feeding the signal developed over a one Meg resistance, into a transconductance amplifier courtesy of a donated LM358 there was enough variation for the STM32 ADC to reliably detect the difference between unfilled and filled check-boxes on the filled-in program cards.

The CPU required 12-bit opcodes, which obviously implies 12 photodiodes and 12 LEDs to read each word. The PixelBlaze board does not have this many analog inputs. A simple trick was instead of having discrete inputs, all 12 photodiodes were wired in parallel and fed into a single input amplifier. To differentiate the different bits, the illumination LEDs instead were charlieplexed, thus delivering the individual bits as a sequence of values into the ADC, for subsequent de-serialising. The demonstration video shows that it works, with a program loaded from a card and kicked into operation manually. Such fun!

Punch cards usually have a hole through them and can be read mechanically, and are a great way to configure testers like this interesting vacuum valve tester we covered a short while back.

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Amphibious Dragster Drives On Water

Dragsters are typically about peak performance on a tarmac drag strip. [Engineering After Hours] took a different tack, though, building a radio-controlled amphibious dragster intended to cross small bodies of water.

The build is based on a Traxxas Raptor RC car. However, it’s been heavily reworked from a pickup-like design to become a dragster with a motor mounted in the rear. It’s also been fitted with a foam underbody to allow it to float when stationary. The rear tires have been replaced with 3D-printed versions with large paddles, which provide propulsion in the water.

Initial tests showed the car struggled to make progress in the water, as the paddle tires tended to drag the rear end deeper under water. The tiny dragster tires up front didn’t help it steer, in water either. Large foam discs were added to the front tires to enable them to act as better rudders.

Fitted with its water tires and foam floatation aids, the car can only drive slowly on land, but [Engineering After Hours] points out this is enough to call it amphibious. It does a better job at skittering around on water, and it was able to cross a local pond at low speed.

We’ve seen some other creative techniques for making amphibious vehicles, like these crazy star-shaped wheels. Video after the break.

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Simple Plywood Lamp Has Neat Hidden Switch

Shortly after the development of the electric light came the light switch, presumably. Of course, obvious switches are old-hat, and this neat lamp build from [Giovanni Aggiustatutto] goes with a design that’s altogether more coy.

The lamp itself is a minimalist modern design, with a cube-like body constructed out of plywood. It was easily constructed by simply stacking up several layers of plywood to create the form. Inside the housing, a bulb holder was installed hooked up to a Shelly smart relay to enable the lamp to be used as a smart device. The relay also has a switch input for direct control. This is hooked up to a micro-switch that is tucked into the base. Tilting the lamp to one side triggers the micro-switch and turns the lamp on and off as desired.

Overall, it’s a simple build that is elegant and functional. It eschews switches on the lamp cord and other fussy details, while featuring both smart control and a direct switch as well. We’ve featured some other great lamps before, too. Video after the break.

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