This year has been the year of home video conferencing. If you are really on the ball, you’ve managed to put some kind of green screen up so you can hide your mess and look as though you are in your posh upper east side office space. However, most of the consumer video conferencing now has some way to try to guess what your background is and replace it even without a green screen. The results, though, often leave something to be desired. A recent University of Washington paper outlines a new background matting procedure using machine learning and, as you can see in the video below, the results are quite good. There’s code on GitHub and even a Linux-based WebCam filter.

The algorithm does require a shot of the background without you in it, which we imagine needs to be relatively static. From watching the video, it appears the acid test for this kind of software is spiky hair. There are several comparisons of definitely not bald people flipping their hair around using this method and other background replacers such as the one in Zoom.

The quality of the results depends somewhat on how many pixels the filter can work with, so 4K video seemed to do better than lower resolutions. Even then, it isn’t perfect, but it does seem like it did a better job than some of the existing tools. If you try it yourself, we did read that you want to avoid blocking bright light, especially during background capture, and try to keep lighting constant. For prolonged use, it may be helpful to re-take the background image as light conditions drift.

As you might expect, you are going to need a big video card to do this in real-time. This is especially true since the algorithm seems to work better with 4K input. However, if you are doing video production in post, you can probably trade hardware for time.

We’ve seen a similar effort with DeepBackSub. Once you have this working, you can build a mirror to improve your video conference eye contact.

source https://hackaday.com/2020/12/22/the-world-is-your-green-screen/

Astronomy fans were recently treated to the Great Conjunction, where Jupiter and Saturn appear close together from the perspective of our planet Earth. Astronomy has given us this and many other magnificent sights, but we can get other senses involved. Science News tells of explorations into adapting our sense of hearing into tools of astronomical data analysis.

Data visualization has long been a part of astronomy, but they’re not restricted to charts and graphs that require a trained background to interpret. Every “image” generated using data from radio telescopes (like the recently-lost Arecibo facility) are a visualization of data from outside the visible spectrum. Visualizations also include crowd pleasing false-color images such as The Pillars of Creation published by NASA where interstellar emissions captured by science instruments are remapped to colors in the visible spectrum. The results are equal parts art and science, and can be appreciated from either perspective.

Data sonification is a whole other toolset with different strengths. Our visual system evolved ability to pick out edges and patterns in spatial plots, which we exploit for data visualization. In contrast our aural system evolved ability to process data in the frequency domain, and the challenge is to figure out how to use those abilities to gain scientifically relevant data insight. For now this field of work is more art than science, but it does open another venue for the visually impaired. Some of whom are already active contributors in astronomy and interested in applying their well-developed sense of hearing to their work.

Of course there’s no reason this has to be restricted to astronomy. A few months ago we covered a project for sonification of DNA data. It doesn’t take much to get started, as shown in this student sonification project. We certainly have no shortage of projects that make interesting sounds on this site, perhaps one of them will be the key.

source https://hackaday.com/2020/12/22/adding-space-music-to-the-astronomy-toolbox/

[Wesley Kagan] is building a Corvette with a V12 engine swap. Much of the driveline will be entirely replaced, which means the components to drive the mechanical speedometer and tachometer will no longer be present in the final car. Instead, [Wesley] came up with his own electronic gauge conversion to do the job.

It’s a build that respects the original aesthetic of the car, reusing the original gauges but driving them differently. In place of the original mechanical drives from the transmission and distributor respectively, the speedometer and tach instead get servos installed in the back with a 3D printed gear train. The odometer gets its own continuous rotation servo, too. An Arduino Nano is used to drive the servos, using data from a GPS module and the car’s ignition system.

Files are available for anyone wishing to 3D print parts to modify their own gauges. We can’t wait to see how the gauges look when finally installed. We can imagine some teething problems with slew rate or update speed, but we’re sure it’s nothing [Wesley] can’t engineer out with a few revisions. Custom gauges are something we’ve seen a few times around these parts; this digital setup is particularly useful for engine data. Video after the break.

source https://hackaday.com/2020/12/22/v12-corvette-gets-electronic-gauge-mod/

[Will Cogley]’s mechanized gauntlet concept sure has a hypnotizing look to it, and it uses only a single motor. Underneath the scales is a rod with several cams, each of which moves a lever up and down in a rippling wave as it rotates. Add a painted scale to each, and the result is mesmerizing. This is only a proof of concept prototype, and [Will] learned quite a few lessons when making it, but the end result is a real winner of a visual effect.

The gauntlet uses one motor, 3D printed hardware, and a mechanical linkage between the wrist and the rest of the forearm. Each of the scales is magnetically attached to the lever underneath, which provides some forgiveness for when one inevitably bumps into something. You can see the gauntlet without the scales in the video, embedded below the break, which should make clear how the prototype works.

The scales were created with the help of a Mayku desktop vacuum former by making lightweight copies of 3D printed scales. Interestingly, 3D printing each scale with full supports made for a useful mold; there was no need to remove supports from underneath the prints, because they are actually a benefit to the vacuum forming process. When vacuum forming, the presence of overhangs can lead to plastic wrapped around the master, trapping it, but the presence of the supports helps prevent this. 3D prints don’t hold up very well to the heat involved in vacuum forming, but they do well enough for a short run like this. Watch it in action and listen to [Will] explain the design in the video, embedded below.

Vacuum forming has been around for almost 70 years, but it’s still seeing updates. For example, combining hydrographic printing techniques with vacuum forming to create full-color objects.

source https://hackaday.com/2020/12/22/watch-this-scaly-gauntlets-hypnotizing-rippling-waves/

There’s no question that being able to see who’s at your front door from your computer or mobile device is convenient, which is why the market is currently flooded with video doorbells. Unfortunately, it’s not always clear who else has access to the images these devices capture. Organizations such as the Electronic Frontier Foundation have argued that by installing one of these Internet-connected cameras on their front door, consumers are unwittingly contributing to a mass surveillance system that could easily be turned against them.

Luckily, there’s a solution. As [Sebastian] shows in his latest project, you can build your own video doorbell that replicates the features of the commercial offerings while ensuring you’re the only one who has access to the data by leveraging open source, community developed projects such as ESPHome and Home Assistant. At the same time, modern manufacturing techniques like desktop 3D printing and low-cost PCB fabrication mean your DIY doorbell doesn’t have to look like you made it yourself.

The project starts with a custom PCB that combines the ESP32, a camera module, a capacitive touch sensor, a relay to optionally trigger an electronic door lock, and a DC-DC converter that will let you power the device from a wide range of input voltages. The board even has a spot where you can solder on an additional 8 MB of external PSRAM for the ESP32, which will enable the chip to capture higher resolution video.

The electronics are housed in a minimalistic 3D printed enclosure that would fit right in alongside similar gadgets from the likes of Ring and Arlo; especially if you have access to a CNC and can cut the front panel out of acrylic. The lighted touch sensor looks phenomenal, and really gives the device a professional feel. That said, it doesn’t look like the case would last very long if exposed to harsh weather and there are some obvious physical security issues with this approach. But to be fair, we’ve seen the same problem with commercial hardware.

Naturally with a project like this, the hardware is only half of the story. It takes a considerable amount of software poking and prodding to get things like mobile device notifications working, and as a special added annoyance, the process is different depending on which MegaCorp produced the OS your gadget is running. [Sebastian] has documented the bulk of the process in the video after the break, but the finer points will likely need some adjustment depending on how you want to set things up.

This is an exceptionally impressive project for sure, but if the whole slick futuristic look isn’t your style, you could always opt to go with the DIY video door bell that looks like it came from an alternate reality version of 1986.

source https://hackaday.com/2020/12/22/diy-esp32-video-doorbell-locks-out-big-brother/

The SENT protocol, standing for Single Edge Nibble Transmission, is used for sensors that need to send high-resolution data while keeping system costs low. It’s most typically used in the automotive world, where it can be found in such parts as throttle-by-wire pedals and temperature sensors. [Mark Smith] set out to see if he could get the Pi Zero to read such sensors without the use of an intermediate microcontroller.

[Mark]’s initial attempts relied on Python and the RPI.GPIO library. Unfortunately, the overheads introduced made decoding SENT traffic impossible. Undeterred, [Mark] pressed on, leveraging the pigpio library and its callback function which allowed sampling at up to one microsecond. This was fast enough to read the messages from a LX3302A inductive position sensor that uses the protocol.

It’s a project that could prove useful for those trying to work with certain sensors who want to avoid adding complexity to a Raspberry Pi project. Files are available on Github for the curious. We’ve seen other direct sensor builds with the Pi, before too – like this power monitoring system. Video after the break.

source https://hackaday.com/2020/12/22/implementing-sent-sensors-on-the-raspberry-pi/

Long before the current smartwatch craze, Texas Instruments released the eZ430-Chronos. Even by 2010s standards, it was pretty clunky. Its simple LCD display and handful of buttons also limited what kind of “smart” tasks it could realistically perform. But it did have one thing going for it: it’s SDK allowed users to create a custom firmware tailored to their exact specifications.

It’s been nearly a decade since we’ve seen anyone dust off the eZ430-Chronos, but that didn’t stop [ogdento] from turning one into a custom alert device for a sick family member. A simple two-button procedure on the watch will fire off emails and text messages to a pre-defined list of contacts, all without involving a third party or have to pay for a service contract. Perhaps most importantly, the relatively energy efficient eZ430 doesn’t need to be recharged weekly or even daily as would be the case for a modern smartwatch.

To make the device as simple as possible, [ogdento] went through the source code for the stock firmware and commented out every function beyond the ability to show the time. With the watch’s menu stripped down to the minimum, a new alert function was introduced that can send out a message using the device’s 915 MHz CC1101 radio.

The display even shows “HELP” next to the appropriate button so there’s no confusion. A second button press is required to send the alert, and there’s even a provision for canceling it should the button be pressed accidentally.

On the receiving side, [ogdento] is using a Raspberry Pi with its own CC1101 radio plugged into the USB port. When the Python scripts running on the Pi picks up the transmission coming from the eZ430 it starts working through a list of recipients to send messages to. A quick look at the source code shows it would be easy to provide your own contact list should you want to put together your own version of this system.

We’ve seen custom alert hardware before, but like [ogdento] points out, using the eZ430-Chronos provides a considerable advantage in that its a turn-key platform. It’s comfortable to wear, reliable, and fairly rugged. While some would argue against trusting independently developed code for such a vital task, at least the hardware is a solved problem.

source https://hackaday.com/2020/12/22/ti-ez430-chronos-turned-medical-alert-wearable/

Here’s a simple tip from [Andy], whose Raspberry Pi projects often travel with him outside the workshop: he suggests adding a small HDMI-to-USB video capture device to one’s Raspberry Pi utility belt. As long as there is a computer around, it provides a simple and configuration-free way to view a Raspberry Pi’s display that doesn’t involve the local network, nor does it require carrying around a spare HDMI display and power supply.

The usual way to see a Pi’s screen is to either plug in an HDMI display or to connect remotely, but [Andy] found that he didn’t always have details about the network where he was working (assuming a network was even available) and configuring the Pi with a location’s network details was a hassle in any case. Carrying around an HMDI display and power supply was also something he felt he could do without. Throwing a small HDMI-to-USB adapter into his toolkit, on the other hand, has paid off for him big time.

The way it works is simple: the device turns an HDMI video source into something that acts just like a USB webcam’s video stream, which is trivial to view on just about any desktop or laptop. As long as [Andy] has access to some kind of computer, he can be viewing the Pi’s display in no time.

Many of his projects (like this automated cloud camera timelapse) use the Pi camera modules, so a quick way to see the screen is useful to check focus, preview video, and so on. Doing it this way hit a real sweet spot for him. We can’t help but think that one of these little boards could be a tempting thing to embed into a custom cyberdeck build.

source https://hackaday.com/2020/12/21/heavy-raspberry-pi-user-keep-an-hdmi-to-usb-capture-device-around/

Here’s a simple tip from [Andy], whose Raspberry Pi projects often travel with him outside the workshop: he suggests adding a small HDMI-to-USB video capture device to one’s Raspberry Pi utility belt. As long as there is a computer around, it provides a simple and configuration-free way to view a Raspberry Pi’s display that doesn’t involve the local network, nor does it require carrying around a spare HDMI display and power supply.

The usual way to see a Pi’s screen is to either plug in an HDMI display or to connect remotely, but [Andy] found that he didn’t always have details about the network where he was working (assuming a network was even available) and configuring the Pi with a location’s network details was a hassle in any case. Carrying around an HMDI display and power supply was also something he felt he could do without. Throwing a small HDMI-to-USB adapter into his toolkit, on the other hand, has paid off for him big time.

The way it works is simple: the device turns an HDMI video source into something that acts just like a USB webcam’s video stream, which is trivial to view on just about any desktop or laptop. As long as [Andy] has access to some kind of computer, he can be viewing the Pi’s display in no time.

Many of his projects (like this automated cloud camera timelapse) use the Pi camera modules, so a quick way to see the screen is useful to check focus, preview video, and so on. Doing it this way hit a real sweet spot for him. We can’t help but think that one of these little boards could be a tempting thing to embed into a custom cyberdeck build.

source https://hackaday.com/2020/12/21/heavy-raspberry-pi-user-keep-an-hdmi-to-usb-capture-device-around/

It is a common problem these days. You have a piece of code in C or C++. Maybe it is older code. Or maybe you prefer prototyping your ideas using C. But, inevitably, someone now wants your code to run in a Web browser. The options for making this happen have expanded quite a bit lately and one possibility is Cheerp, an open-source compiler that handles up to C++ 17 and can output to WebAssembly, JavaScript, or asm.js.

The compiler is free to use for GPLv2 projects. If you aren’t open yourself, it looks like you have to cut a deal to use Cheerp with its maker, Learning Technologies.

Traditionally, you’d use Emscripten to do something like this. According to the project’s site, Cheep generates faster and smaller WebAssembly than Emscripten and has several advantages if you compile to JavaScript. For example, they claim to have better dynamic memory handling, more efficient access to the DOM, and better JavaScript interoperability.

The Hello World example is, understandably, a little underwhelming, but does show some special features that allow direct access to the browser. They do point out that you can ignore that and use things like printf or cout if you aren’t worried about performance. A better place to start if you want to do anything serious is the pong game example.

If you haven’t been keeping up with WebAssembly, we can get you started. If you don’t think any of this would have application in an embedded system, we’ll refer you to Olaf.

source https://hackaday.com/2020/12/21/c-compiler-targets-the-web/

The spark plug was a key invention in the history of the internal combustion engine, allowing combustion to be easily controlled and engines to rev faster than messy earlier designs. Mid-century cars tended to rely on points ignition with a distributor and coil, however more modern designs place a coil on top of each individual spark plug. [Roger Moore] decided to build a similar setup for a small model engine on his workbench.

The rig is built with an Arduino, a flyback transformer, a smattering of MOSFETs and passives, an IGBT and a capacitor. The Arduino outputs PWM through a MOSFET which is stepped up through the transformer, and then charges the capacitor. The capacitor is then discharged into a coil mounted on top of the sparkplug of the single-cylinder engine, which fires the spark. The timing of the spark is determined by a Hall effect sensor reading a magnet placed on the flywheel.

Later development aims to shrink the system further to fit on a V10 design [Roger] is planning to make. It’s been done on a small scale before, and we’d love to see another tiny engine with way too many cylinders. Video after the break.

[Thanks to Andy Pugh for the tip!]

source https://hackaday.com/2020/12/21/coil-on-plug-ignition-for-tiny-engines/

In the grand scheme of things, a single human lifetime is a drop in the bucket. Even if we don’t like to acknowledge it, we all know the meter is running so to speak. Yet you’re still squandering your precious time on this Earth by reading Hackaday instead of doing something constructive. Of course nobody is burning up more time on this site than those of us who are writing it all, so don’t feel too bad.

To remind us that life is fleeting, [Dries Depoorter] has designed the Shortlife: a device that counts down until your expected departure date. Before you get too excited, it can’t predict the future. The gadget is programmed with the vital statistics for the individual user, and data provided by the World Health Organization is used to calculate how much of your estimated life expectancy has already elapsed. Some would find this information depressing, while others will no doubt look at it as a source of inspiration. Us? We just think its a slick piece of gear.

The Shortlife is made up of a custom PCB mounted to a marbled block of recycled plastic. On the board there’s an ATmega328 microcontroller, a MAX7219 LED driver, and of course the red LED segment displays. Three of them are the classic seven count, while the rightmost display sports fourteen segments for a bit of added accuracy. All the user has to do if they want to watch their remaining time slip away is plug the device into a USB power source and set the current time.

We’ve seen similar mortal countdown clocks in the past, but the Shortlife certainly brings a certain level of elegance to the idea. Plus we also like the fact that you’re just a line of code or two away from having the display tick down to some other date in the future when that whole existential crisis kicks in

source https://hackaday.com/2020/12/21/watch-life-tick-away-one-led-segment-at-a-time/

An Australian radio telescope picked up unusual signals back in 2019 and thinks they originated from Proxima Centauri, a scant 4.3 light years from our blue marble. Researchers caution that it almost certainly is a signal of human or natural origin and that more analysis will probably show it didn’t come from Proxima Centauri. But they can’t yet explain it.

The research is from the Breakthrough Listen project, a decade-long SETI project. The 980 MHz BLC-1 signal, as it’s called, meets the tests that identify the signal as interesting. It has a narrow bandwidth, it drifts in frequency consistent with a signal moving away or towards the Earth, and it disappears when the radio telescope points elsewhere.

The project has been running since 2015 and this was the first signal their algorithms flagged as requiring further analysis. However, the researchers admit the algorithm is intentionally optimistic. After all, you’d rather have false positives to filter out than have any false negatives.

Unfortunately, since the initial set of detections, the team hasn’t found any more signals from the same part of the sky. Proxima Centauri is interesting because it is among our closest neighbors and it is known to have at least two planets, one of which we think could support life.

The 210 foot Parkes radio telescope — better known locally as “the dish” — that detected the signal dates back to 1961 and was the point of reception for the Apollo 11 moon landing. Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) operates the facility and the picture above is courtesy of CSIRO, CC-BY-3.0.

While you might not have room in your backyard for a 210-foot dish, you can build something more modest. We wonder if this signal will remain a mystery like the Wow signal?

source https://hackaday.com/2020/12/21/did-et-finally-call-us/

At one end of the synthesizer world, there stands commercial instruments designed for the ultimate in sound quality and performance, tailored to the needs of professional musicians. On the other, there are weird, wacky prototypes and artistic builds that aim to challenge our conception of what a synth should be. The VOC-25 by [Love Hultén] falls firmly in the latter category.

The synth is built around the Axoloti Core, a microcontroller board set up for audio experimentation. Packing stereo DACs and ADCs, and MIDI input and output, it’s the perfect base for such a project. Loaded up with vocal samples, it’s played by a keyboard in a fairly typical sense. Where things get interesting is the panel containing 25 sets of plastic teeth. The teeth open and close when the user plays the corresponding note, thanks to a solenoid. Along with the clacking sound of the machinery and pearly whites themselves, it adds quite a creepy vibe to the piece.

With its clean pastel enclosure, we can imagine this piece as the star of an avant-garde filmclip, or merely something to terrify children at a Maker Faire. It’s a fun build, to be sure. We’ve seen some other great experimental synths over the years, too – this 48 Game Boy build comes to mind. Video after the break.

source https://hackaday.com/2020/12/21/we-bet-youve-never-seen-a-pink-denture-synth/

Smartphones are portals to an overwhelming torrent of information. Yes, they’re a great way to find out the time, your bus schedule, and the weather, but they’re also full of buzzers and bells going off every three minutes to remind you that your uncle has reposted a photo of the fish he caught ten years ago. Sometimes, it’s better to display just the essentials, and that’s what Weather Note does.

It’s built around the Adafruit Feather Huzzah, a devboard built around the venerable ESP8266. It’s a great base for an Internet of Things project like this one, with WiFi built-in and ready to go. The Weather Note talks to a variety of online platforms to scrape weather data and helpful reminders, with the assistance of If This Then That, or IFTTT. Reminders to walk the dog or get some milk are displayed on a small OLED screen, while there’s also a bunch of alphanumeric displays for other information. WS2812 LEDs are used behind a shadowbox to display weather conditions, with cute cloud, rain, and sun icons. It’s all wrapped up in a tidy frame perfect for the mantlepiece or breakfast table.

It’s a great build to learn about programming for the Internet of Things, and with those bright LED displays, it’s probably a viable nightlight too. It’s a rare project that can both tell you about the weather and keep you from stubbing your toe in the kitchen, after all. Those desiring a stealthier build should consider going down the smart mirror route instead. Video after the break.

source https://hackaday.com/2020/12/20/weather-note-tells-you-what-you-need-to-know-and-no-more/

Water droplets are beautiful things, though photographing them can prove difficult without a little help. Precise timing is key, and that’s what led [Alex Pikkert] to build a timing controller to help nail the perfect shot.

It’s a job that’s ideally suited for the average microcontroller. In this case, [Alex] chose the venerable Arduino Uno. Paired with a bunch of buttons and a 16 x 2 character LCD, it has a simple-to-navigate interface for dialling in a shot. The trick to splash and droplet photography is to first open a valve to release a droplet, and then fire a flash a set time after to capture the droplet in flight, after it’s hit the surface of the liquid. [Alex]’s design uses a MOSFET to trigger the water valve, and optoisolators to safely trigger the flash and camera.

[Alex] has gotten some impressive results with the rig, and it would serve as a great starting point for anyone looking to get into the field. We’ve seen similar builds before, too. If you’ve got your own fancy photography rig for those otherwise-impossible shots, be sure to drop us a line!

source https://hackaday.com/2020/12/20/splash-droplet-photos/

If development platforms were people, Google would be one of the most prolific serial killers in history. Android Things, Google’s attempt at an OS for IoT devices, will officially start shutting down on January 5, 2021, and the plug will be pulled for good a year later. Android Things, which was basically a stripped-down version of the popular phone operating system, had promise, especially considering that Google was pitching it as a secure alternative in the IoT space, where security is often an afterthought. We haven’t exactly seen a lot of projects using Android Things, so the loss is probably not huge, but the list of projects snuffed by Google and the number of developers and users left high and dry by these changes continues to grow.

By now you’ve probably heard about the drone operator who was fined a cool $182,000 by the FAA for violations of the rules regarding safe drone operation. It may seem exorbitant, but when you dig a little deeper, it seems like the drone pilot, who goes by the handle “Mikey” on YouTube, pretty much had it coming. He has been operating drones in the Center City area of Philadelphia for a while now, in flagrant disregard for FAA rules like not operating in beyond line of sight, not operating at night, and not flying in restricted areas. Mikey, who by the way doesn’t have a remote pilot’s certificate, did all this and more, and posted everything on YouTube. We normally give the benefit of the doubt and take pity on people who get hassled for just enjoying their hobbies, but after listening to about three minutes of Mikey’s schtick on YouTube, we decided that he probably had it coming.

Still looking for the perfect gift this holiday season? What about the gift of silicon? DIY chip maker Sam Zeloof is auctioning off chips from his first production batch of homemade ICs, cooked up right in his garage. The Z1 chip, which we featured back in 2018 when Sam first announced it, is a dual-differential amplifier with six FETs and a handful of other components, packaged in a 14-pin ceramic DIP. The current bid is up to $315, which seems a fair price considering all the work Sam put into this, plus the fact that proceeds go to keeping Sam’s fab lab running.

We’re normally loathe to bring up anything that has to do with the safety of 3D-printing, as it mostly just devolves into a flame war in the comments section. But what the heck — it’s Christmas! There’s news of a paper, apparently presented at last week’s Society of Risk Analysis annual meeting, that reportedly confirms what most of us intuitively know already: that the fumes from 3D printers aren’t great to inhale. Specifically, the researchers found that emissions from ABS filament were moderately toxic to human lung cells, while minimally toxic to rats. There’s a lot of detail missing here — for example, “lung cells” implies a cell culture, which is not the same thing as observing clinical changes in someone’s lungs, nor is a rat always a good model for what’s going to happen in humans. Still, we’re keen to read the actual paper and dive into the details. Until then, we’ll probably keep on printing — just maybe with the window cracked.

Looking for a fun project to while away some time between Christmas and New Year? You could do worse than by trying to tune into slow-scan TV broadcasts from the International Space Station. The ARISS program, or Amateur Radio aboard the ISS, has been operating from on high for 20 years now, and to celebrate they’ve scheduled SSTV broadcasts from December 24 to December 31. SSTV is an amateur radio mode that transmits low-def, static images on amateur bands that can be received with simple equipment, and without a license. If you want to give it a shot, you should check out Jenny’s how-to article for the basics on getting an RTL-SDR hooked up and getting the right software installed. You also need an antenna — this simple v-dipole should do the trick. Happy watching!

source https://hackaday.com/2020/12/20/hackaday-links-december-20-2020/

A lighthouse beams light out to make itself and its shoreline visible. [Daniel’s] lighthouse has the opposite function, using lasers to map out the area around itself. Using an Arduino and a ToF sensor, the concept is relatively simple. However, connecting to something that rotates 360 degrees is always a challenge.

The lighthouse is inexpensive — about $40 — and small. Small enough, in fact, to mount on top of a robot, which would give you great situational awareness on a robot big enough to support it. You can see the device in action in the video below.

This lighthouse uses a common solution to the rotating connection problem: a slip ring. While these are mechanical, commercial units can be relatively reliable. To route all the signals, the slip ring needs six wire capsules meaning there are six wires that logically pass through the rotating part. The drive motor spins at 60 RPM, but there are two sensors 180 degrees apart to double the scanning rate. The 3D printed housing uses PLA and looks great.

Of course, the real trick will be using all this data meaningfully in your robot or whatever is listening to the lighthouse. That, however, is a different topic. If you think two ToF sensors are good, why not try three?

 

source https://hackaday.com/2020/12/20/lidar-house-looks-good-looks-all-around/

All this ongoing forced togetherness is great, but sometimes you just need to be able to pretend you’re alone so you can get some work done. So, how do you keep family members out of your home office? Our own [Bob Baddeley]’s free/busy indicator is about as simple as it gets.

The best part is that the status can been seen on both sides of the door so you don’t forget to keep it updated. Or maybe it’s the super-low part count. There’s no BLE, LoRa, or Wi-Fi, just two sets of red and green LEDs, a three-way switch, and a power source. Well, and current-limiting resistors of course.

[Bob] already had all the components on hand, including the nifty enclosure, which is another great thing about this build. Like [Bob] says, you could house the control side of this circuit in just about anything you’ve got lying around.

Young children might abuse this one, but this status indicator that lets the family request your presence with the push of a button.

source https://hackaday.com/2020/12/20/status-display-lets-them-know-you-cant-play/

All this ongoing forced togetherness is great, but sometimes you just need to be able to pretend you’re alone so you can get some work done. So, how do you keep family members out of your home office? Our own [Bob Baddeley]’s free/busy indicator is about as simple as it gets.

The best part is that the status can been seen on both sides of the door so you don’t forget to keep it updated. Or maybe it’s the super-low part count. There’s no BLE, LoRa, or Wi-Fi, just two sets of red and green LEDs, a three-way switch, and a power source. Well, and current-limiting resistors of course.

[Bob] already had all the components on hand, including the nifty enclosure, which is another great thing about this build. Like [Bob] says, you could house the control side of this circuit in just about anything you’ve got lying around.

Young children might abuse this one, but this status indicator that lets the family request your presence with the push of a button.

source https://hackaday.com/2020/12/20/status-display-lets-them-know-you-cant-play/

All this ongoing forced togetherness is great, but sometimes you just need to be able to pretend you’re alone so you can get some work done. So, how do you keep family members out of your home office? Our own [Bob Baddeley]’s free/busy indicator is about as simple as it gets.

The best part is that the status can been seen on both sides of the door so you don’t forget to keep it updated. Or maybe it’s the super-low part count. There’s no BLE, LoRa, or Wi-Fi, just two sets of red and green LEDs, a three-way switch, and a power source. Well, and current-limiting resistors of course.

[Bob] already had all the components on hand, including the nifty enclosure, which is another great thing about this build. Like [Bob] says, you could house the control side of this circuit in just about anything you’ve got lying around.

Young children might abuse this one, but this status indicator that lets the family request your presence with the push of a button.

source https://hackaday.com/2020/12/20/status-display-lets-them-know-you-cant-play/

You have to be of a certain vintage to remember doing research on microfilm and microfiche. Before the age of mass digitization of public records, periodicals, and other obscure bits of history, dead-tree records were optically condensed onto fine-grain film, either in roll form or as flat sheets, which were later enlarged and displayed on a specialized reader. This greatly reduced the storage space needed for documents, but it ended up being a technological dead-end once the computer age rolled around.

This was the problem [CuriousMarc] recently bumped into — a treasure trove of Hewlett-Packard component information on microfiche, but no reader for the diminutive datasheets. So naturally, he built his own microfiche reader. In a stroke of good luck, he had been gifted a low-cost digital microscope that seemed perfect for the job. The scope, with an HD camera and 5″ LCD screen, was geared more toward reflective than transmissive use, though, so [Marc] had trouble getting a decent picture of the microfiches, even with a white paper backing.

Version 2.0 used a cast-off backlight, harvested from a defunct DVD player screen, as a sort of light box for the stage of the microscope. It was just about the perfect size for the microfiches, and the microscope was able to blow up the tiny characters as well as any dedicated microfiche reader could, at a fraction of the price. Check out the video below for details on the build, as well as what [Marc] learned from the data sheets about his jackpot of HP parts.

With the wealth of data stored on microforms, we’re surprised that we haven’t seen any readers like this before. We have talked about microscopic wartime mail, though.

source https://hackaday.com/2020/12/20/this-expedient-microfiche-reader-illuminates-retro-datasheets/

While things like object oriented computing and model-view-controller are old hat these days, when Smalltalk burst on the scene, many people had never heard of these new ideas. While the little language with roots at Xerox and based on Simula never caught fire, it was very influential in a number of ways. Now Smalltalk luminary [Dan Ingalls] has the Smalltalk Zoo, a collection of Smalltalk-related items including several historical simulations you can run in your browser.

We were especially impressed with the AltoSmalltalk-72 simulation since our chances of running a real Alto are pretty slim. The JavaScript behind it actually implements the Alto’s Nova instruction set. The emulator then runs a 45-year old memory dump from a real Alto. According to [Dan], there’s no file system and the microcoded music and animation instructions are missing, but he hopes someone will add them as a spare-time project.

There are a few other project suggestions for anyone brave enough to dig into this old software. We found it amusing that the Smalltalk-72 Javascript interpreter runs over 500 times the speed of the original and has “nearly unlimited” object storage.

In Smalltalk everything is an object. With things like the turtle graphics object (@) and you can say things like:

@ go 50 turn 90 go 50 turn 90 go 50 turn 90 go 50\

It is less amusing when someone tells you they sent the + message to the 3 object in order to add something to 3, but that’s object-orientation for you. If you don’t know Smalltalk, try the snippets you can find on the right side of the emulator.

source https://hackaday.com/2020/12/20/making-a-little-smalltalk/

Despite the lingering reality that most of us don’t have what it takes to make it to the upper reaches of the Hit Parade, there remain many who still harbour a secret desire to make music. What better way to realise this dream, than by making [Blog Hoskins’] $20 MIDI synth project!

The write-up goes into a staggering level of detail to ensure that it’s accessible at all levels, to the extent that a complete beginner could probably assemble a working synth by following it. For some of the fancier parts of front panel there’s a reliance on a laser cutter, but even without such wizardry the Average Joe with an electric drill could still do a pretty good job.

Behind the panel though it’s not short on features it’s a surprisingly simple design. At its heart is an Arduino Nano, surrounded by potentiometers and switches for user control, and an opto-coupler for the MIDI lines. Sadly for analogue synth fans there’s not much else in the way of circuitry, but the point of a build such as this one is to create a playable instrument with the shortest path to usability. A video full fo those glorious synth sounds is below the break.

MIDI synthesisers are a frequent feature here at Hackaday. A recent favourite is this four-voice instrument that uses servos as its active element.

source https://hackaday.com/2020/12/20/a-synth-of-your-own-for-not-a-lot/

A smart thermostat is nothing new. But making one built a decade or more ago takes a few tricks. If you want to upgrade your thermostat without replacing it, [geektechniquestudios] shares their solution using a Raspberry Pi Zero to smarten up that dumb controller.

The hardware is decidedly simple: just a Pi Zero and a pair of relays. The relays act as button presses to the old thermostat. The software, though, is decidedly complex. There’s a React server and a Redis database along with some other bits and pieces.

The project is a work in progress, so you’ll probably have to figure a bit out for yourself. Even better, there is room to contribute back. In fact, the project page has a wish list of additions including Google home integration, scheduled temperature changes, and a few others.

Fake button presses takes a bit of finesse on the software side. After all, the computer can jam a button many times faster than a human with a mechanical switch can, and that’s bound to confuse an old circuit, especially if it denounces the switches.

This project is relatively simple to some others we’ve seen. A Pi Zero is cheap, but we’ve seen similar projects done for even less. For example, a $5 Sonoff box can do the same job.

source https://hackaday.com/2020/12/19/old-thermostat-gets-smarts/