Swimming Pool Lap Counter Relies On Ultrasound

August 2, 2020 by 8 Comments

Swimming is a great way to exercise, both for the cardiovascular benefits and the improved muscle tone. However, while he’s a fan, [Peter Quinn] sometimes finds it hard to keep track of how far he’s gone when he gets in the zone. Obviously, the solution is an electronic lap counter, which [Peter] promptly set about creating.

The build is based around an ultrasonic distance sensor, which is triggered when it detects a swimmer approaching the end of the lane. It’s run by an Arduino Nano, which is also set up to announce the accumulated distance with a speech synth library. [Peter] notes there have been some stumbling blocks thus far, necessitating modifications along the way. Water ingress into the ultrasonic sensor has required the installation of a protective shroud, while battery operation has required a module to properly handle the lithium-polymer battery.

While we might hesitate to bring a takeaway container full of wires, circuit boards and an LED display to a public pool for fear of being deemed a bomber, the basic bones of the project are a great way to approach the problem. There’s plenty of scope to implement laptiming too, as we’ve seen in other sporting builds!

Digital Caliper Talks For Accessibility, With This App

August 2, 2020 by 38 Comments

A good instrument stays with its owner for a lifetime, becoming part of their essential trusted toolkit to be consulted as a matter of habit. If you use a caliper to measure dimensions  you’ll know this, and a quick glance at its scale or digital display will be second nature. But if you aren’t fortunate enough to have the eyesight to see the caliper, then it’s off-limits, and that’s something [Naomi Wu] has addressed with her open-source accessible speaking caliper app. It’s an Android app that connects to digital calipers that contain Bluetooth connectivity, and as well as speaking aloud the caliper reading it also displays it in very large text on the device screen. As well as the source link from which you can build the app, it’s available for installation directly from the Google Play Store.

If you’re used to [Naomi] from her video tours of the electronics businesses in her native Shenzhen, her eye-catching wearable projects, or her exploits with an industrial CNC machine in her living room, you might be interested to know that aside from this app she’s been a long-time proponent of open-source in China. She was responsible among other projects for the Sino:bit educational computer board, which holds the distinction for her of having secured the first ever Chinese OSHWA certification.

You can see the caliper app in action below the break.

Continue reading “Digital Caliper Talks For Accessibility, With This App” →

Art Piece Builds Up Images With Dots On Thread

August 1, 2020 by 7 Comments

Hackers being as a rule practical people, we sometimes get a little guff when we run a story on an art installation, on the grounds of not being sufficiently hacky. We understand that, but sometimes the way an artist weaves technology into their pieces is just too cool to pass us, as with this thread-printing art piece entitled On Framing Textile Ambiguities.

We’ll leave criticism of the artistic statement that [Nathalie Gebert]’s installation makes to others more qualified, and instead concentrate on its technical aspects. The piece has four frames made mainly from brass rods. Three of the frames have vertical rods that are connected to stepper motors and around which is wrapped a single thread. The thread weaves back and forth over the rods on one frame, forming a flat surface that constantly changes as the rods rotate, before heading off to do the same on the others. The fourth frame has a platen that the thread passes over with a pen positioned right above it. As the thread pauses in its endless loop, the pen clicks down onto it, making a dot of color. The dots then wend their way through the frame, occasionally making patterns that are just shy of recognizable before morphing into something new. The video below shows it better than it can be easily described.

Love it or hate it, you’ve got to admit that it has some interesting potential as a display. And it sort of reminds us of this thread-art polar robot, although this one has the advantage of being far simpler.

Continue reading “Art Piece Builds Up Images With Dots On Thread” →

A Homebrew Radio, As All The Best Homebrew Radios Should Be

August 1, 2020 by 9 Comments

It started with an old TV sound chip, and some curiosity. The TDA1701 that [Philip Bragg] found in a box of junk is a complete FM IF strip and audio power amplifier from the golden age of analogue PAL televisions, and while it was designed for the 5.5 MHz or 6 MHz FM subcarrier of European broadcast TV, he found it worked rather well at the more usual 10.7 MHz of a radio receiver. There followed a long thread detailing the genesis bit-by-bit of a decent quality VHF radio receiver, built dead-bug-style on a piece of PCB material.

The TDA1701 was soon joined by a couple of stages of IF amplification with a ceramic filter, and then by several iterations of a JFET mixer. A varicap tuned MOSFET RF amplifier followed, and then a local oscillator. Finally it became a fully-functional FM radio, with probably far better performance than most commercial radios. He admits tuning is a little impractical though, with what appears to be a cermet preset potentiometer covering the entire band.

We suspect this project isn’t finished, and we hope he posts the schematic. But it doesn’t really matter if he doesn’t, because the value here isn’t in the design. Instead it lies in the joy of creating an ad-hoc radio just for the fun of it, and that’s something we completely understand.

We’ve covered a lot of radios in our time, and while it might be the first to feature a TV sound chip, it’s not the first built on bare PCB.

VK-01 Is A Bartender You Don’t Need To Tip

August 1, 2020 by 15 Comments

[Donald Bell’s] robotic bartender entry into the 2020 Cocktail Robotics Grand Challenge is one of those things that sounds easy until you start getting into the details. After all, how hard is it to dispense some liquids into a glass? Harder than you might think. Sure there are pumps — [Donald] uses peristaltic pumps — but there’s also two Raspberry Pis, an ESP8622, and at least one more microcontroller lurking underneath. You can see a video about the device below.

Even if you don’t want a refreshing libation, you’ll probably like the VK-01’s Bladerunner cyberpunk styling. What we really enjoyed about the post was that it took you through the concept sketches, some of the design trades, and even a cardboard prototype.

Continue reading “VK-01 Is A Bartender You Don’t Need To Tip” →

Playing The Pixelflut

August 1, 2020 by 7 Comments

Every hacker gathering needs as many pixels as its hackers can get their hands on. Get a group together and you’ll be blinded by the amount of light on display. (We propose “a blinkenlights” as the taxonomic name for such a group.) At a large gathering, what better way to show of your elite hacking ability than a “competition” over who can paint an LED canvas the best? Enter Pixelflut, the multiplayer drawing canvas.

Pixelflut has been around since at least 2012, but it came to this author’s attention after editor [Jenny List] noted it in her review of SHA 2017. What was that beguiling display behind the central bar? It turns out it was a display driven by a server running Pixelflut. A Pixelflut server exposes a display which can be drawn on by sending commands over the network in an extremely simple protocol. There are just four ASCII commands supported by every server — essentially get pixel, set pixel, screen size, and help — so implementing either a client or server is a snap, and that’s sort of the point.

While the original implementations appear to be written by [defnull] at the link at the top, in some sense Pixelflut is more of a common protocol than an implementation. In a sense, one “plays” one of a variety of Pixelflut minigames. When there is a display in a shared space the game is who can control the most area by drawing the fastest, either by being clever or by consuming as much bandwidth as possible.

Then there is the game of who can write the fastest more battle-hardened server possible in order to handle all that traffic without collapsing. To give a sense of scale, one installation at 36c3 reported that a truly gargantuan 0.5 petabytes of data were spent at a peak of rate of more than 30 gigabits/second, just painting pixels! That’s bound to bog down all but the most lithe server implementation. (“Flut” is “flood” in German.)

While hacker camps may be on pause for the foreseeable future, writing a performant Pixelflut client or server seems like an excellent way to sharpen one’s skills while we wait for their return. For a video example check out the embed after the break. Have a favorite implementation? Tell us about it in the comments!

Continue reading “Playing The Pixelflut” →

How Many Of You Are There, Really?

August 1, 2020 by 40 Comments

We’re now accustomed to hearing, “We’re all special in our own unique ways.” But what if we weren’t really aren’t all that unique? Many people think there are no more than two political opinions, maybe a handful of religious beliefs, and certainly no more than one way to characterize a hack. But despite this controversy in other aspects as life, at least we can all rely on the uniqueness of our individual names. Or can you?

You ever thought there were too many people named [insert name here]? Well, [Nicole] thought there were too many people who shared her name in her home country of Belgium and decided to make an art piece out of it.

She was able to find data on the first names of people in Belgium and wrote a Python script…er…used Excel to find the number of Nicoles in each zip code. She then created a 3D map of Belgium divided into each province with the height of each province proportional to the number of Nicoles in that area. A pretty simple print job that any standard 3D printer can probably do these days.

Not much of a “do something” hack, but could make for a cool demotivational ornament that will constantly remind us just how unique we really are.

Happy hacking!

Continue reading “How Many Of You Are There, Really?” →