Arduino Hacks

3039 Articles

Insecure Surveillance Cameras Provide Dystopian Peep Show

February 18, 2020 by 29 Comments

It probably doesn’t surprise you to hear there are tens of thousands of web-connected cameras all over the world that are set to take the default credentials. Actually, there are probably more than that out there, but we can assure you that at least 70,000 or so are only a click away. With this project, [carolinebuttet] proves that it’s quite possible to make art from our rickety, ridiculous surveillance state — and it begins with a peephole perspective.

The peephole in your own front door grants you the inalienable right to police your porch, stoop, or patch of carpet in the apartment building’s hallway while going mostly undetected. In Virtual Peephole, the peephole becomes a voyeuristic virtual view of various corners of the world.

Slide aside the cover, and an LDR connected to an Arduino Micro detects the change in light level. This change makes the Micro send a key press to a Raspberry Pi, which fetches a new camera at random and displays it on a screen inside the box. You can peep a brief demo after the break, followed by a couple of short build/walk-through videos.

If you’re a peephole people watcher, put a camera in there and watch from anywhere.

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Nixie Clock Claims To Be Simplest Design

February 14, 2020 by 29 Comments

[Engineer2you] built a nixie tube clock and claims it is the simplest design. We felt like that was a challenge. In this design, the tubes are set up as a matrix with optoisolators on each row and column. With 60 segments, the matrix allows you to control it all with 16 bits. There are six columns, each corresponding to a digit. That means each row has 10 lines.

The Arduino code reads the clock and produces the output to the tubes fast enough that your eye perceives each digit as being always on, even though it isn’t.

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RF Shield Turns Arduino (And PC) Into Shortwave Radio

February 14, 2020 by 10 Comments

Microcontrollers tend to consume other kinds of electronics. A project you might once have done with a 555 now probably has a cheap microcontroller in it. Music synthesizers? RC controllers? Most likely, all microcontroller-based now. We always thought RF electronics would be immune to that, but the last decade or two has proven us wrong. Software-defined radio or SDR means you get the RF signal to digital as soon as possible and do everything else in software. If you want an introduction to SDR, Elektor now has an inexpensive RF shield for the Arduino. The Si5351-based board uses that oscillator IC to shift RF signals down to audio frequencies and then makes it available to the PC to do more processing.

The board is available alone or as part of a kit that includes a book. There’s also a series of Elektor articles about it. There’s also a review video from Elektor about the board in the video, below.

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Arduino Drives A 600-Character Display

February 14, 2020 by 7 Comments

[Peterthinks] admits he’s no cabinet maker, so his projects use a lot of hot glue. He also admits he’s no video editor. However, his latest video uses some a MAX7219 to create a 600 character scrolling LED sign. You can see a video of the thing, below. Spoiler alert: not all characters are visible at once.

The heart of the project is a MAX7219 4-in-1 LED display that costs well under $10. The board has four LED arrays resulting in a display of 8×32 LEDs. The MAX7219 takes a 16-bit data word over a 10 MHz serial bus, so programming is pretty easy.

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All Band Radio Uses Arduino And Si4730

February 12, 2020 by 45 Comments

It is getting harder and harder to tell homemade projects from commercial ones. A good case in point is [Mirko’s] all band radio which you can see in the video below the break. On the outside, it has a good looking case. On the inside, it uses a Si4730 radio which has excellent performance that would be hard to get with discrete components.

The chip contains two RF strips with AGC, built-in converters to go from analog to digital and back and also has a DSP onboard. The chip will do FM 64 to 108 MHz and can demodulate AM signals ranging from 153 kHz to 279 kHz, 520 kHz to 1.71 MHz, and 2.3 MHz to 26.1 MHz. It can even read RDS and RBDS for station information. The output can be digital (in several formats) or analog.

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Laser Tachometer Knows How Fast You Were Spinning Back There

February 12, 2020 by 25 Comments

Does your drill go as fast as the manufacturer says it will? Well, you’d need a tachometer to figure that out. They’re not that expensive to buy, but as [Elite Worm] shows, they’re not that expensive to make, either — about $10 total if you get your parts from the right places. Lucky for you, he has links to everything.

Really, the links are just the tip of the iceberg here as far as the gifts that [Elite Worm] bestows upon those who choose to undertake this project. The build video (after the break, as usual; our favor to you) is fantastic, and would be perfect for a beginner because of the entrancing speed at which he builds it. The video is straight up relaxing to watch, whether you want to build one or not.

It’s a fairly simple circuit — just push the momentary switch, and the laser diode and sensor pair count the revolutions over one second. The Arduino Nano multiplies this number by 60 and displays the RPM on the OLED screen. What we absolutely love about this build is the care that taken in designing the case. There’s a designated spot for each component, and the ones without their own special holder are kept in place with printed crossbar pieces. [Elite Worm] says this has a higher refresh rate than his store-bought tacho, and we say it looks way cooler, too.

Still don’t want to make one yourself? Well, okay. Before you buy one, try using your phone to calculate RPM.

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Building A Sound Activated Shop Fan With Arduino

February 10, 2020 by 12 Comments

Whether you’re using a soldering iron or a table saw, ventilation in the shop is important. Which is why [Atomic Dairy] built a monster air cleaner called the Fanboy that looks like it should be mounted under the wing of an F-15. Realizing a simple switch on the wall wouldn’t do this potent air mover justice, they decided to build a sound activated controller for it.

It’s certainly an elegant idea. The sound created once they kick on their woodworking tools would be difficult to miss by even the most rudimentary of sound-detection hardware. At the most basic level, all they needed was a way for an Arduino to throw a relay once the noise level in the room reached a specific threshold.

Of course it ended up getting a bit more complicated than that, as tends to happen with these kinds of projects. For one, the sound doesn’t directly control the solid state relay used in the fan controller. When the microphone equipped Arduino detects enough noise, it will start a timer that keeps the fan running for two hours. If the tool keeps running, then more time gets added to the clock. This ensures that the air in the room is well circulated even after the cutting and sanding is done.

[Atomic Dairy] also added a few additional features so they could have more direct control over the fan. There’s a button to manually add more time to the clock, and another button to shut it down. There’s even support for a little wireless remote control, so the fan can be operated without having to walk over to the control panel.

We’ve seen some impressive air circulation and dust collection systems over the years, but finding a way to elegantly switch them on and off has always been a problem given the wide array of tools that could be in use at any given time. Sound activation isn’t a perfect solution, but it’s certainly one we’d consider for our own shop.

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