The Simplest Microwave Receiver

We are used to microwave receivers requiring complex chipsets and exacting PCB layouts, but as [CHZ-soft] has shown, it does not always have to be that way. With nothing more complex than a germanium point-contact diode and an oscilloscope, you can quickly, easily, and cheaply resolve microwave signals, as we are shown with a 2.4GHz wireless mouse.

Of course, there’s nothing new here, what we’re being shown is the very simplest incarnation of a crystal set. It’s a wideband device, with only the length of the wires providing any sort of resonance, but surprisingly with the addition of a very selective cavity resonator it can be turned into a useful receiver. Perhaps the most interesting take-away is that the germanium point-contact diode — once a ubiquitous component — has almost entirely disappeared. In most applications it has been supplanted by the Schottky diode, but even those usually don’t quite possess the speed in the point contact’s home ground of radio detection. This is a shame, because there are still some bench-level projects for which they are rather useful.

So if you have a point contact diode and AM radio doesn’t attract, give it a go as a microwave detector. And if the point contact diode has attracted your interest then you may want to read our piece on Rufus Turner, who brought us its archetype, the 1N34A.

Via Hacker News.

Hackaday Links: June 7, 2020

For many of us who were in college at the time, the 1989 release of Will Wright’s classic SimCity sounded the death knell of our GPAs. Being able to create virtual worlds and then smite them with a tornado or a kaiju attack was the stuff of a procrastinator’s dreams. We always liked the industrial side of the game best, and took great pains in laying out the factory zones, power plants, and seaports. Those of a similar bent will be happy to know that Maxis, the studio behind the game, had a business simulations division, and one of their products was a complete refinery simulator the studio built for Chevron called, unsurprisingly, SimRefinery. The game, which bears a striking resemblance to SimCity, has been recovered and is now available for download, which means endless procrastination by playing virtual petrochemical engineer is only a mouse click away.

Speaking of time wasters, we stumbled upon another simulation this week that sucked away a couple of hours of productivity. As reports, YouTuber called Information Zulu has a 24/7 live stream showing arrivals and departures at Los Angeles International Airport. That may sound boring, but the cameras used to watch the runways are virtual, and the planes are animated based on ADS-B data being scooped up by an RTL-SDR dongle. We pinged Information Zulu and asked for a rundown of the gear behind the system, but never heard back. If we do, we’ll post a full article on what we learned, because the level of detail is amazing. The arriving and departing planes sport the correct livery for the airline, the current weather conditions are shown, taxiing is shown in real time, and there’s even an audio feed from air traffic control.

If you’re looking to gain back a little of the productivity lost to the last two items, Digi-Key might be able to help with their new PCB Builder service. All you have to do is upload your gerbers and select your materials, and they’ll give you options for a bunch of different quick-turn fabrication houses. Looks mighty convenient.

Steve Mould dropped a video this week about vibration analysis. That might not sound very exciting, but the fascinating bit is how companies are now using motion amplification video techniques to show how and where industrial equipment is moving, even if those motions are too subtle to be seen by the naked eye. It’s frankly terrifying to see how pipes flex and tanks expand and contract, and how pumps and motors move relative to each other. The technique used is similar to the way a person’s pulse can be detected on a video by the subtle color change as blood rushes into capillaries. We’d love to see someone tackle a homebrew version of this so we can all see what’s going on around us.

And finally, we want to remind everyone that the Hackaday Prize is back, and that you should get your entries going. What’s new this year is the Dream Team challenges, where four worthy non-profits organizations will each assemble a three-person team to work on a specific pain-point in their process. The application deadline has been extended to June 9, and there are two $3,000 microgrants, one in June and one in July, for each team member. So look through the design briefs and see if your skills match their needs.

Build This Cyberdeck In A Cave With A Box Of Scraps

Desktop 3D printing has been a big enabler for the cyberdeck community, as it’s allowed individuals to create unique frames and enclosures which would have been far more difficult and time consuming to produce using traditional methods. But what if you don’t have access to a well-stocked workspace, and need to do your building with the bare minimum of equipment? In that case, [ALX] recently put together a minimalistic design that can be assembled with off-the-shelf components and basic tools.

It’s the ideal cyberdeck for the neophyte, as all the parts are widely available and relatively inexpensive. While it might not be a customized as something with a fully 3D printed frame, we think it nails the look and utility that are the hallmarks of a proper deck.

The key to this build is the SmartiPi Touch case, which puts the Raspberry Pi and touch screen on a hinged panel. These hinges happen to be compatible with GoPro-style mounts, so with a few extension pieces, the panel can be lifted up high enough that it can be folded over the keyboard. The base of the SmartPi Touch case is then attached to the bottom of the keyboard with nothing more exotic than double-sided tape. Here [ALX] is using a Happy Hacking KeyBoard Lite 2, but you could substitute it with whatever you have handy.

On the other hand, if 3D printing out the frame isn’t a problem for you, this miniature cyberdeck we covered recently could be a great alternative if you’re looking to get started in the burgeoning world of bespoke mobile computers.

Adjustable Jig Eases PCB Stencil Alignment Process

PCB stencils make application of solder paste a snap, but there’s a long, fussy way to go before the paste goes on. You’ve got to come up with some way to accurately align the stencil over the board, which more often than not involves a jury-rigged setup using tape and old PCBs, along with a fair amount of finesse and a dollop of luck.

Luckily, [Valera Perinski] has come up with a better way to deal with stencils. The Stencil Printer is a flexible, adjustable alignment jig that reduces the amount of tedious adjustment needed to get things just so. The jig is built mostly from aluminum extrusions and 3D-printed parts, along with a bunch of off-the-shelf hardware. The mechanism has a hinged frame that holds the stencil in a fixed position above a platen, upon which rests the target PCB. The board is held in place by clamps that ride on threaded rods; with the stencil flipped down over the board, the user can finely adjust the relative positions of the board and the stencil, resulting in perfect alignment. The video below is mainly a construction montage, but if you skip to about the 29:00 mark, you’ll see the jig put through its paces.

Granted, such a tool is a lot more work than tape and spare PCBs, but if you do a lot of SMD work, it may be worth the effort. It’s certainly less effort than a solder-paste dispensing robot.

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Crate EV Motor Hits Market: The Swindon Powertrain

Last year brought some exciting news from the unlikely quarter of an unexciting industrial estate in the British town of Swindon, the company Swindon Powertrain announced that they’d be marketing an all-in-one electric motor and transmission. Essentially this would be a crate engine for EV conversions, and since it’s pretty small it would be able to be shoehorned into almost any car. So often these announcements later prove to be vapourware, but not in this case, because Swindon Powertrain have announced that you can now order the HPD as they call it, for delivery in August. It’s not entirely cheap at £6400 ($7846) exclusive of British VAT sales tax, but when its integrated transmission and differential is taken into consideration it starts to seem more attractive when compared to engineering a random motor onto an internal combustion engine transmission.

They provide a product page with links to a load of data, installation information, and even a CAD model, as well as an ordering page in their webshop from which you can pay the deposit with the rest presumably payable in August before delivery. There is also a range of optional extras including matched inverters, drive shafts, a limited slip differential, and a coolant pump, which makes the whole ever more attractive as a package. 80kW should be enough to lend sprightly performance to all but the largest of cars, so we’ll expect to see this motor ever more often in years to come.

There is already a thriving home-made EV scene which we don’t expect this unit to displace. Instead it will find a niche at the professional and semi-professional conversion level, and we wouldn’t be surprised to see an aftermarket springing up offering ready made subframes to fit it to popular cars. If it is a success there will inevitably be copies and probably at a lower price, so it could be the start of a wave of very interesting conversion options. We hope that Swindon Powertrain will do well with it, and will manage to stay one step ahead of the upstarts. You can read our coverage of its announcement and their electric Mini prototype here.

Thanks [Carl Pickering] for the tip.

Bust Your Own Ghosts With A PKE Meter

You know, we wouldn’t be that surprised if aliens or ghosts show up for real before this year is out. If paranormal becomes part of the new normal, it might be nice to have a PKE meter that can detect spirits and help get a head start on figuring out what they want from us.

Yes, that’s right — instead of just lighting up whenever ghosts are near, [starscream205]’s meter goes the extra yard and translates spiritual energy into English words that scroll across the LED matrix. Inside is a Raspberry Pi 3B+ and a sense HAT, which takes spatial and environmental readings and assigns different words based on the results.

Now [starscream205] can go fearlessly into the night, guided by the night vision camera on the end, and watch for ghosts on the screen. Instead of a typical Pi-compatible screen, this is from a car back-up camera system and has been modified to work with the Pi.

We’ve seen a few PKE meters around here before, but they usually do things such as detect radiation. It’s nice to see one that’s faithful to the original purpose.