A Unique Microphone Preamp

July 7, 2018 by Tom Nardi 5 Comments

We live in a world in which nearly any kind of gadget or tool you can imagine is just a few clicks away. In many respects, this has helped fuel the maker culture over the last decade or so; now that people aren’t limited to the hardware that’s available locally, they’re able to create bigger and better things than ever before. But it can also have a detrimental effect. One has to question, for instance, why they should go through the trouble of building something themselves when they could buy it, often for less than the cost of the individual components.

The critic could argue that many of the projects that grace the pages of Hackaday could be supplanted with commercially available counterparts. We don’t deny it. But the difference between buying a turn-key product and building an alternative yourself is that you can make it exactly how you want it. That is precisely why [Sam Izdat] created this truly one of a kind microphone preamplifier. Could he have bought one online for cheaper? Probably. Could he have saved himself an immense amount of time and effort? Undoubtedly. Do we care? Not in the slightest.

The amplifier is based on the Texas Instruments INA217 chip, with an Arduino Nano and 128×64 OLED display providing the visualization. [Sam] was able to find a bare PCB for a typical INA217 implementation on eBay for a few bucks (see what we mean?), which helped get him started and allowed him to spend more time on the software side of things. His visualization code offers a number of interesting display modes, uses Fast Hartley Transforms, and very nearly maxes out the Arduino.

But perhaps no element of this build is as unique as the case. The rationale behind the design is that [Sam] wanted to compartmentalize each section of the device (power supply, amplifier, visualization) to avoid any interference. The cylindrical shapes were an issue of practicality: the compartments were constructed by using a hole saw to make wooden discs, which were then glued together and hollowed out. The case was stained and coated with polyurethane, but due to some slightly overzealous use of glue and fillers, the coloring isn’t uniform. This gives the final piece a somewhat weathered look, in sharp contrast to the decidedly high-tech looking display.

Overall, this build reminds us of the modular 3D printed amplifier we saw earlier in the year combined with these speaker-integrated Arduino VU meters.

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Driftwood Binary Clock Is No Hollow Achievement

July 2, 2018 by Kristina Panos 10 Comments

It’s about time we had another awesome clock post around here. [Mattaw] has liked binary clocks since he was 0 and decided to make one in stunning fashion by using driftwood, nature’s drillable, fillable enclosure.

That beautiful wiring job on the RGB LEDs was done in 18g copper. To keep the LEDs aligned during soldering, he drilled a a grid of holes just deep enough to hold ’em face down. There’s an IR remote to set the time, the color, and choice of alarm file, which is currently set to modem_sound.mp3.

Under the wood, there are a pair of Arduino Nanos, an mp3 decoder board, and an RTC module. Why two Nanos, you ask? Well, the IR interrupts kept, uh, interrupting the LED timing. The remote feature was non-negotiable, so [mattaw] dedicated one Nano to receive remote commands, which it streams serially to the other. Here’s another nice touch: there’s an LDR in one of the nooks or crannies that monitors ambient light so the LEDs are never too bright. Don’t wait another second to check it out—we’ve got 10 videos of it after the break.

Believe it or not, this isn’t the first binary clock we’ve seen. This honey of a clock uses RGB LEDs to tell the time analog style.

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Aquarium Controller Starring Arduino Gets A Long Video Description

July 1, 2018 by Al Williams 4 Comments

There’s an old saying that the cobbler’s children have no shoes. Sometimes we feel that way because we stay busy designing things for other people or for demos that we don’t have time to just build something we want. [Blue Blade Fish] wanted to build an Arduino-based aquarium controller. He’s detailed the system in (so far) 14 videos and it looks solid.

This isn’t just a simple controller, either. It is a modular design with an Arduino Mega and a lot of I/O for a serious fish tank. There are controls for heaters, fans, lights, wave makers and even top-off valves. The system can simulate moonlight at night and has an LCD display and keys. There’s also an Ethernet port and a Raspberry Pi component that creates a web interface, data storage, and configures the system. Even fail safes have been designed into the system, so you don’t boil or freeze expensive fishes. No wonder it took 14 videos!

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R/C Rocket-Beest Burns Up Fuses Out There Alone

June 29, 2018 by Kristina Panos 8 Comments

We’re beginning to think the “S” in [Jeremy S Cook] stands for strandbeest. He’ll be the talk of the 4th of July picnic once he brings out his latest build—a weaponized, remote-controlled strandbeest that shoots bottle rockets. There are a bank of money shots up on Imgur.

This ‘beest is the natural next step after his remote-controlled walker, which we featured a month or so ago. Like that one, the locomotion comes from a pair of micro gear motors that are controlled by an Arduino Nano over Bluetooth. The pyrotechnics begin when nitinol wire cleverly strung across two lever nuts is triggered. All the electronics are housed inside a 3D-printed box that [Jeremy] designed to sit in the middle of the legs. We love the face plate he added later in the build, because those gumdrop LED eyes are sweet.

Can you believe that this vehicle of destruction began as a pile of innocent, pasta-colored pieces of kit? We dig the camouflaged battleship paint job, ’cause it really toughens up the whole aesthetic. And really, that’s probably what you want if you’re driving around a spindly beast that can just shoot rockets whenever. Let’s light this candle after the break, shall we?

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LoRa With The ESP32

June 24, 2018 by Al Williams 20 Comments

If you are interested in deploying LoRa — the low power long-range wireless technology — you might enjoy [Rui Santos’] project and video about using the ESP32 with the Arduino IDE to implement LoRa. You can see the video below. He uses the RFM95 transceivers with a breakout board, so even if you want to use a different processor, you’ll still find a lot of good information.

In fact, the video is just background on LoRa that doesn’t change regardless of the host computer you are using. Once you have all the parts, getting it to work is fairly simple. There’s a LoRa library by [Sandeep Mistry] that knows how to do most of the work.

Although the project uses an RFM95, it can also work with similar modules such as the RFM96W or RFM98W. There are also ESP32 modules that have compatible transceivers onboard.

This is one of those projects that probably isn’t useful all by itself, but it can really help you get over that hump you always experience when you start using something new. Once you have the demo set up, it should be easy to mutate it into what you really need.

We’ve been talking about LoRa a lot lately. We’ve even seen it commanding drones.

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Arduino And Pidgin C++

June 23, 2018 by Al Williams 87 Comments

What do you program the Arduino in? C? Actually, the Arduino’s byzantine build processes uses C++. All the features you get from the normal libraries are actually C++ classes. The problem is many people write C and ignore the C++ features other than using object already made for them. Just like traders often used pidgin English as a simplified language to talk to non-English speakers, many Arduino coders use pidgin C++ to effectively code C in a C++ environment. [Bert Hubert] has a two-part post that isn’t about the Arduino in particular, but is about moving from C to a more modern C++.

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TerraDome Gives Plants And Dinosaurs A New Home

June 22, 2018 by Sven Gregori 1 Comment

Housing exotic plants or animals offer a great opportunity to get into the world of electronic automation. When temperature, light, and humidity ranges are crucial, sensors are your best friend. And if woodworking and other types of crafts are your thing on top, why not build it all from scratch. [MagicManu] did so with his Jurassic Park themed octagonal dome built from MDF and transparent polystyrene.

With the intention to house some exotic plants of his own, [MagicManu] equipped the dome with an Arduino powered control system that regulates the temperature and light, and displays the current sensor states on a LCD, including the humidity. For reasons of simplicity regarding wiring and isolation, the humidity itself is not automated for the time being. A fan salvaged from an old PC power supply provides proper ventilation, and in case the temperature inside the dome ever gets too high, a servo controlled set of doors that match the Jurassic Park theme, will automatically open up.

[MagicManu] documented the whole build process in a video, which you can watch after the break — in French only though. We’ve seen a similar DIY indoor gardening project earlier this year, and considering its simple yet practical application to learn about sensors, plus a growing interest in indoor gardening itself (pun fully intended), this certainly won’t be the last one.
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