Arduino Hacks

3048 Articles

Espresso Machine Now Powers Plants

February 22, 2020 by 6 Comments

This thing has what plants crave! No, not electrolytes exactly — just water, light, and moisture polling every 30 minutes. We think it’s fitting to take something that once manufactured liquid liveliness for humans and turn it into a smart garden that does the same thing for plants.

So let’s just get this out of the way: the espresso machine was abandoned because it was leaking water from a gasket. [The Plant Bot] cleaned it up, replaced the gasket, and got it brewing, and then it started leaking hot water again from the same gasket. We might have gone Office Space on this beautiful machine at that point, but not [The Plant Bot].

Down in the dirt, there’s a soil moisture sensor that’s polling every 30 minutes. If the moisture level falls below the threshold set appropriately at a life-sustaining 42%, the Arduino is triggered to water the plant through a relay board using the espresso machine’s original pump. If the plant is dry, the machine will pump water for two seconds every minute until the threshold is met. [The Plant Bot] tied it all together with a nice web interface that shows plant data and allows for changes over Bluetooth.

[The Plant Bot] started by disconnecting the heating element, because plants don’t tend to like hot steam. But if the cup warming tray along the top has a separate heating element, it might be neat to reuse it for something like growing mushrooms, or maintaining a sourdough starter if the temperature is right.

Via r/duino

Bluetooth Intervalometer Makes Time Lapses Easy

February 21, 2020 by 5 Comments

Taking timelapses is a fun pastime of many a photographer. While most modern cameras have some features to pull this off, if you want to get really into it, you’ll want an intervalometer to run the show. Chasing just that, [Zach] decided that rather than buying off-the-shelf, a DIY build was in order.

The build relies on an Arduino Nano to run the show, in combination with the popular HC-05 Bluetooth module. The Bluetooth module allows the device to communicate with a smartphone app which [Zach] created using RoboRemo. This is a platform that makes creating custom USB, WiFI and Bluetooth apps easy for beginners. The app sends instructions to the intervalometer regarding the number of photos to take, and the time to wait between each shot. Then, it triggers the time lapse, and the Arduino triggers the camera by shorting the relevant pins on a TRS plug inserted into the camera.

It’s a straightforward build that most hackers could probably complete with parts from the junk box. Plus, building your own offers the possibility of customising it exactly to your needs. Of course, you can eschew modernity and do things mechanically instead. Video after the break.

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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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