Cheap And Effective Mosquito Trap Looks Like A Disco

August 3, 2020 by Adil Malik 34 Comments

Words cannot quite articulate the collective loathing humankind has for mosquitoes, and rightfully so! These parasite peddling, blood sucking little critters are responsible for a great deal of human suffering. Mosquito-borne diseases such as malaria still account for a significant proportion of human mortality, especially in under-developed parts of the world . So it’s no wonder that people try to reduce their numbers; see this latest $40 mosquito trap by [jacobsk]. (Video, embedded below.)

The idea is critically simple, opening up the potential for widespread deployment. The base and body of the trap are made out of three five-gallon buckets with a mini desk fan sandwiched in between, providing suction into the main trap bin. An opening is cut in the top bucket as a point of entry, and an old school incandescent blacklight is mounted in the centre, with just enough IR and UV output to entice these little vermin, who will definitely regret mistaking it for a black-light rave.

[jacobsk] also does a very good job of showing every step of its construction in his videos. Whilst this solution is purposefully low tech, check out this admittedly overcooked way of killing mosquitoes, with a laser turret.

Continue reading “Cheap And Effective Mosquito Trap Looks Like A Disco” →

Teardown: The Writer Word Processor

June 9, 2020 by Tom Nardi 60 Comments

For modern students, the spiral notebook has given way to the laptop and the pocket calculator has been supplanted by the smart phone. We’re not just talking about high school and college, either. Today, the education of even grade school children is intrinsically linked with technology. While some might question the wisdom of moving away from the pencil and pad at such a young age, there’s little question that all the kids stuck at home right now due to COVID-19 would have had a much harder time transitioning to remote learning otherwise.

But that certainly wasn’t the case when Advanced Keyboard Technologies released the Writer in 2003. Back then, five years before the first netbooks hit the market, you’d be hard pressed to find a laptop cheap enough to give to a grade school student. In comparison, these small electronic word processors could be purchased for as little as $150. Not only was the initial price low, but the maintenance costs were almost negligible. They ran for hundreds of hours on a standard AA batteries, and didn’t require schools to have any IT staff to manage them. Sure they couldn’t get on the Internet or even run any software, but they would give students a chance to hone their keyboarding skills. Continue reading “Teardown: The Writer Word Processor” →

Run Your Favorite 8-bit Games On An ESP32

June 9, 2020 by Kerry Scharfglass 20 Comments

Here at Hackaday HQ we’re no strangers to vintage game emulation. New versions of old consoles and arcade cabinets frequently make excellent fodder for clever hacks to cram as much functionality as possible into tiny modern microcontrollers. We’ve covered [rossumur]’s hacks before, but the ESP_8-bit is a milestone in comprehensive capability. This time, he’s topped himself.

There isn’t much the ESP 8-bit won’t do. It can emulate three popular consoles, complete with ROM selection menus (with menu bloops). Don’t worry about building a controller, just connect any old (HID compliant) Bluetooth Classic keyboard or WiiMote you have at hand. Or if that doesn’t do it, a selection of IR devices ranging from joysticks from the Atari Flashback 4 to Apple TV remotes are compatible. Connect analog audio and composite video and the device is ready to go.

The system provides this impressive capability with an absolute minimum of components. Often a schematic is too complex to fit into a short post, but we’ll reproduce this one here to give you a sense for what we’re talking about. Come back when you’ve refreshed your Art of Electronics and have a complete understanding of the hardware at work. We never cease to be amazed at the amount of capability available in modern “hobbyist” components. With such a short BOM this thing can be put together by anyone with an ESP-32-anything.

There’s one more hack worth noting; the clever way [rossumur] gets full color NTSC composite video from a very busy microcontroller. They note that NTSC can be finicky and requires an extremely stable high speed reference clock as a foundation. [rossumur] discovered that the ESP-32 includes a PLL designed for audio work (the “APLL”) which conveniently supports fractional components, allowing it to be trimmed to within an inch of the desired frequency. The full description is included in the GitHub page for the project and includes detailed background of various efforts to get color NTSC video (including the names of a couple hackers you might recognize from these pages).

Continue reading “Run Your Favorite 8-bit Games On An ESP32” →

A Pulse Oximeter From Very Little

May 16, 2020 by Jenny List 31 Comments

Against the backdrop of a global respiratory virus pandemic, it’s likely that more than a few readers have been thinking about pulse oximeters. You may even have looked at one closely and seen that it’s little more than a device which shines light through your finger, and wondered how they work. It’s something [Giulio Pons] has done, and to show us how it’s done he’s created a working pulse oximeter of his own.

He started with an infra-red heartbeat sensor module, which is revealed as nothing more than an IR LED and a photodiode. Sampling the output from the photodiode allows measurement of heartbeat, but gives not clue as to oxygen saturation. The interesting part comes via the property of red light in that it’s transmission through flesh varies with oxygen saturation, so adding a red LED and alternately measuring from the IR and red illuminations allows a saturation figure to be derived.

Commercial pulse oximeters are pretty cheap, so many of us will no doubt simply order one from the usual sources and call it good. But it’s always interesting to know how any device works, and this project reveals something simpler than we might have expected. If pulse oximeters interest you, compare it with this one we featured a few years ago.

Any Remote Can Be A Universal Remote

May 1, 2020 by Jenny List 23 Comments

Everyone has a stack of old infra-red remote controllers lying around, for devices that have long since shuffled off this mortal coil. Containing little more than an application-specific encoder chip, keyboard, and IR LED, they’re of little use unless you happen to have another device that uses the same encoding scheme. For [RiYa] though they represent an opportunity, to be repurposed into controllers for other devices. How? Hijack the bitstream with an ATtiny13 microcontroller, re-encode it, and send it out afresh into the ether from the LED. It’s a gloriously simple solution which we can’t help applauding, and has the potential to cheaply replace all those universal remotes.

The ATtiny itself along with a buffer to drive the LED is mounted on a small breakout board and concealed within the shell of the remote. We don’t learn much about the power supply arrangement, but we’d expect the ATtiny to be on its most power-sipping behaviour as anything which would shorten the battery life of a remote would be unlikely to be popular with a couch potato forced to change AA cells every few weeks. There’s a plan for a learning mode to make it more like a commercial universal remote, but for now the translation is hard coded.

Of course, should you lack a handy old remote to play with, you can always try a smartphone.

The Nintendo Game Boy Color Is An Aircon Remote

April 29, 2020 by Jenny List 5 Comments

Those of you who are familiar with 1990s handheld consoles may recall that Nintendo’s Game Boy Color had an infra-red receiver and transmitter. The thought of a handheld computer with infra-red capabilities interested [jg], who immediately set about converting it into a remote control for an air conditioner.

The Game Boy doesn’t have dedicated infra-red remote control hardware, instead the IR diodes appear to be connected to I/O lines. Thus the bitstream bas to be bit-banged, and takes the processor’s entire attention when transmitting. The software is neatly placed on a reprogrammed bootleg cartridge.

It’s an interesting read in terms of the approach to reverse engineering, for example finding the parameters of 37 kHz infra-red remote control by trial and error rather than by a quick read up on the subject, or searching for information on National air conditioners and finding nothing, but not searching the National brand itself to find that a search on Panasonic air conditioners would likely give all the information needed. But the end result operates the appliance, so it’s good to record a success.

This isn’t the first time we’ve seen a Game Boy control something, though we can’t recall seeing another using the IR. Need a brilliant overview of the Game Boy? We’ve got you covered.

Thanks [Roel] for the tip.

Header image: Evan-Amos / Public domain.

Teardown Of Oddball Night Vision Shows Off Retro-futuristic Vibe

April 8, 2020 by Donald Papp 14 Comments

Night vision aficionado [Nicholas C] shared an interesting teardown of a Norwegian SIMRAD GN1 night vision device, and posted plenty of pictures, along with all kinds of background information about their construction, use, and mounting. [Nicholas] had been looking for a night vision device of this design for some time, and his delight in finding one is matched only by the number of pictures and detail he goes into when opening it up.

The GN1 rocks an irresistible retro-futuristic look.

What makes the SIMRAD GN1 an oddball is the fact that it doesn’t look very much like other, better known American night vision devices. Those tend to have more in common with binoculars than with the GN1’s “handheld camera” form factor. The GN1 has two eyepieces in the back and a single objective lens on the front, which is off-center and high up. The result is a seriously retrofuturistic look, which [Nicholas] can’t help but play to when showing off some photos.

[Nicholas] talks a lot about the build and tears it completely down to show off the internal optical layout necessary to pipe incoming light through the image intensifier and bend it around to both eyes. As is typical for military hardware like this, it has rugged design and every part has its function. (A tip: [Nicholas] sometimes refers to “blems”. A blem is short for blemish and refers to minor spots on optics that lead to visual imperfections without affecting function. Blemished optics and intensifier tubes are cheaper to obtain and more common on the secondary market.)

In wrapping up, [Nicholas] talks a bit about how a device like this is compatible with using sights on a firearm. In short, it’s difficult at best because there’s a clunky thing in between one’s eyeballs and the firearm’s sights, but it’s made somewhat easier by the fact that the GN1 can be mounted upside down without affecting how it works.

Night vision in general is pretty cool stuff and of course DIY projects abound, like the OpenScope project which leverages digital cameras and 3D printing, as well as doing it the high-voltage image intensifier tube way.