echo

33 Articles

Measuring A Well With Just A Hammer And A Smartphone

December 19, 2024 by 37 Comments

What’s the best way to measure the depth of a well using a smartphone? If you’re fed up with social media, you might kill two birds with one stone and drop the thing down the well and listen for the splash. But if you’re looking for a less intrusive — not to mention less expensive — method, you could also use your phone to get the depth acoustically.

This is a quick hack that [Practical Engineering Solutions] came up with to measure the distance to the surface of the water in a residential well, which we were skeptical would work with any precision due to its deceptive simplicity. All you need to do is start a sound recorder app and place the phone on the well cover. A few taps on the casing of the well with a hammer send sound impulses down the well; the reflections from the water show up in the recording, which can be analyzed in Audacity or some similar sound editing program. From there it’s easy to measure how long it took for the echo to return and calculate the distance to the water. In the video below, he was able to get within 3% of the physically measured depth — pretty impressive.

Of course, a few caveats apply. It’s important to use a dead-blow hammer to avoid ringing the steel well casing, which would muddle the return signal. You also might want to physically couple the phone to the well cap so it doesn’t bounce around too much; in the video it’s suggested a few bags filled with sand as ballast could be used to keep the phone in place. You also might get unwanted reflections from down-hole equipment such as the drop pipe or wires leading to the submersible pump.

Sources of error aside, this is a clever idea for a quick measurement that has the benefit of not needing to open the well. It’s also another clever use of Audacity to use sound to see the world around us in a different way.

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A More Conspicuous Computer Assistant

June 25, 2023 by 11 Comments

Back in the last century, especially in the ’40s to the ’60s, one of the major home decor trends was to install various home appliances, like the television or stereo, into its own piece of furniture. These were usually bulky, awkward, and incredibly heavy. And, since real life inspires art, most of the futuristic sci-fi technology we saw in movies and TV of the time was similarly conspicuous and physical. Not so with modern technology, though, where the trend now is to hide it out of the way and forget it exists. But [dermbrian] wanted some of his modern technology to have some of the mid-century visibility aesthetic so he made some modifications to his Amazon Echo.

The Echo itself remains largely unmodified, other than placing it inside a much larger cookie tin with some supporting electronics. For that, [dermbrian] found a relay board with a built-in microphone which switches the relay off when it detects sound so that when the Echo is activated, the sound from its speaker activates the module. From there it drives a series of blinkenlights which mimic the 60s computer aesthetic. Some custom fabrication and light diffusion methods were needed to get it to look just right, and a switch on the outside can disable the mechanism if it is getting triggered by background noise like music from his stereo.

While the appeal of this style may be lost on anyone who wasn’t a fan of the original Lost in Space, Star Trek, or Jetsons, it certainly holds a special significance for those who grew up in that era. It’s certainly not the first project we’ve seen to take a look back at the aesthetics of bygone eras, either. Take a look at this project which adds lenses to modern displays to give them the impression of antiquated CRT displays.

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Photo of the Echo Dot PCB, highlighting the capacitor that needs to be shorted out for the exploit to work

Squeezing Secrets Out Of An Amazon Echo Dot

April 1, 2023 by 44 Comments

As we have seen time and time again, not every device stores our sensitive data in a respectful manner. Some of them send our personal data out to third parties, even! Today’s case is not a mythical one, however — it’s a jellybean Amazon Echo Dot, and [Daniel B] shows how to make it spill your WiFi secrets with a bit of a hardware nudge.

There’s been exploits for Amazon devices with the same CPU, so to save time, [Daniel] started by porting an old Amazon Fire exploit to the Echo Dot. This exploit requires tactically applying a piece of tin foil to a capacitor on the flash chip power rail, and it forces the Echo to surrender the contents of its entire filesystem, ripe for analysis. Immediately, [Daniel] found out that the Echo keeps your WiFi passwords in plain text, as well as API keys to some of the Amazon-tied services.

Found an old Echo Dot at a garage sale or on eBay? There might just be a WiFi password and a few API keys ripe for the taking, and who knows what other kinds of data it might hold. From Amazon service authentication keys to voice recognition models and maybe even voice recordings, it sounds like getting an Echo to spill your secrets isn’t all that hard.

We’ve seen an Echo hijacked into an always-on microphone before, also through physical access in the same vein, so perhaps we all should take care to keep our Echoes in a secure spot. Luckily, adding a hardware mute switch to Amazon’s popular surveillance device isn’t all that hard. Though that won’t keep your burned out smart bulbs from leaking your WiFi credentials.

Making A Tape Echo The Traditional Way

September 14, 2022 by 12 Comments

[Juan Nicola] has taken inspiration from the musician hackers of old and re-purposed a reel-to-reel tape recorder into a tape-echo for his guitar with a built-in valve amplifier (video in Spanish).

The principle is to record the sound of the guitar onto a piece of moving magnetic tape, then to read it back again a short time later.  This signal is mixed with the live input and re-recorded back onto the tape further back.  The effect is heard as an echo, and this approach was very popular before digital effects became readily available.

[Juan] installed a new read-head onto his Grundig TK40 and managed to find a suitable mechanical arrangement to keep it all in place.  He has since updated the project by moving to a tape loop, allowing an infinite play-time by re-using the same piece of tape over and over.

Turning tape machines into echo effects is not a new idea, and we’ve shown a few of them over the years, but every one is slightly different!

Both versions are shown after the break.  YouTube closed-caption auto-translate might come in handy here for non-Spanish speakers.

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Sound And Light Play Off Acrylic And Wire In This Engaging Circuit Sculpture

February 18, 2022 by 3 Comments

It’s no secret that we really like circuit sculptures around here, and we never tire of seeing what creative ways people come up with to celebrate the components used to make a project, rather than locking them away in an enclosure. And a circuit sculpture that incorporates sound and light in its design is always a real treat to discover.

Called “cwymriad” by its designer, [Eirik Brandal], this sound sculpture incorporates all kinds of beautiful elements. The framework is made from thick pieces of acrylic, set at interesting angles to each other and in contrasting colors. The sound-generating circuit, which uses square wave outputs from an ESP32 to provide carrier and modulation signals for a dual ring modulator, is built on a framework of tinned wires. The sounds the sculpture makes have a lovely resonance to them, like random bells and chimes that fade and mix together. There’s also a matrix of white LEDs that form a sort of digital oscilloscope that displays shifting waveforms in time with the music.

While we like the way this looks and sounds, the real bonus here is the details of construction in the video below. [Eirik]’s careful craftsmanship working with multiple materials is evident throughout; we were especially impressed by the work needed to drill holes for the LED matrix, any one of which slightly out of place would have been painfully obvious in the finished product.

This is far from [Eirik]’s first appearance on these pages. His vacuum tube and silicon “ioalieia” was featured just a few weeks back, and “ddrysfeöd” used the acrylic parts as light pipes in a lovely way.

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Google Sheet showing wins and losses of sports team. Data automated by IFTTT, Alexa, and Particle

An Overly Complicated Method Of Tracking Your Favorite Sports Team

December 4, 2021 by 3 Comments

Much of the world appears to revolve around sports, and sports tracking is a pretty big business. So how do people keep up with their favorite team? Well, [Jackson] and [Mourad] decided to devise a custom IoT solution.

Their system is a bit convoluted, so bear with us. First, they tell Alexa whether or not the team won or lost that week. Alexa then sends that information to IFTTT where two different Particle Argon boards are constantly polling the results to decide how to respond next. One Particle responds by lighting up an LED, green for a win and red for a loss. Another Particle board displays the results on an LCD screen. But this is where things get tricky. One of the more confusing aspects of their design is one of the Particle boards then signals back to IFTTT, telling it to tally the number of wins and losses. This seems a bit roundabout since the system started with IFTTT in the first place. Regardless, they seemed to be happy with the result and I’m sure they learned something in the process.

This project might not fulfill any functional need given that Alexa knows everything about all our lives already and you could just ask her how your favorite team is doing whenever you want to. But hey, we’re all about learning by doing here at Hackaday and we’re all guilty of building useless projects here and there just because we can. In any case, their project could serve as a good intro to integrating your Particle with IFTTT or Alexa since there appears to be quite a bit of probably unnecessary handshaking going on here.

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Dub Siren, a 555-powered synthesizer

Classic Chip Line-Up Powers This Fun Dub Siren Synth

September 24, 2021 by 8 Comments

There’s a certain elite set of chips that fall into the “cold, dead hands” category, and they tend to be parts that have proven their worth over decades, not years. Chief among these is the ubiquitous 555 timer chip, which nearly 50 years after its release still finds its way into the strangest places. Add in other silicon stalwarts like the 741 op-amp and the LM386 audio amp, and you’ve got a Hall of Fame lineup for almost any project.

That’s exactly the complement of chips that powers this fun little dub siren. As [lonesoulsurfer] explains, dub sirens started out as actual sirens from police cars and the like that were used as part of musical performances. The ear-splitting versions were eventually replaced with sampled or synthesized siren effects for recording studio and DJ use, which leads us to the current project. The video below starts with a demo, and it’s hard to believe that the diversity of sounds this box produces comes from just a pair of 555s coupled by a 741 buffer. Five pots on the main PCB control the effects, while a second commercial reverb module — modified to support echo effects too — adds depth and presence. I built-in speaker and a nice-looking wood enclosure complete the build, which honestly sounds better than any 555-based synth has a right to.

Interested in more about the chips behind this build? We’ve talked about the 555 and how it came to be, taken a look inside the 741, and gotten a lesson in LM386 loyalty.

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