Weather Station Predicts Air Quality

February 13, 2022 by Bryan Cockfield 7 Comments

Measuring air quality at any particular location isn’t too complicated. Just a sensor or two and a small microcontroller is generally all that’s needed. Predicting the upcoming air quality is a little more complicated, though, since so many factors determine how safe it will be to breathe the air outside. Luckily, though, we don’t need to know all of these factors and their complex interactions in order to predict air quality. We can train a computer to do that for us as [kutluhan_aktar] demonstrates with a machine learning-capable air quality meter.

The build is based around an Arduino Nano 33 BLE which is connected to a small weather station outside. It specifically monitors ozone concentration as a benchmark for overall air quality but also uses an anemometer and a BMP180 precision pressure and temperature sensor to assist in training the algorithm. The weather data is sent over Bluetooth to a Raspberry Pi which is running TensorFlow. Once the neural network was trained, the model was sent back to the Arduino which is now capable of using it to make much more accurate predictions of future air quality.

The build goes into quite a bit of detail on setting up the models, training them, and then using them on the Arduino. It’s an impressive build capped off with a fun 3D-printed case that resembles an old windmill. Using machine learning to help predict the weather is starting to become more commonplace as well, as we have seen before with this weather station that can predict rainfall intensity.

IR Translator Makes Truly Universal Remote

February 10, 2022 by Bryan Cockfield 19 Comments

Universal remotes are a handy tool to have around if you have many devices that would all otherwise have their own remote controls. Merging them all into a single device leads to less clutter and less frustration, but they are often not truly “universal” as some of them may not support every infrared device that has ever been built. If you’re in a situation like that it’s possible to build a truly universal remote instead, provided you have a microcontroller and a few infrared LEDs on hand.

This was the situation that [Matt] found himself in when his Amazon Fire TV equipment control feature didn’t support his model of speakers. To get around this he programmed an Arduino to essentially translate the IR codes from the remote and output a compatible set of codes to the speakers.This requires both an IR photodiode and an IR LED but little else other than the codes for the remote and the equipment in question. With that all set up and programmed into the Aruino, [Matt]’s remote is one step closer to being truly “universal”.

While [Matt] was able to make use of existing codes in the Arduino library, it is also possible to capture the codes required manually by pointing a remote at a photodiode and programming a microcontroller to capture the codes that you need. [Matt] used a Raspberry Pi to do this when debugging this project, but we’ve also seen this method used with a similar build which uses an ESP8266 to control an air conditioner via its infrared remote control capabilities.

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HDD Centrifuge Puts COVID-19 Testing Lab In A Backpack

February 5, 2022 by Dan Maloney 11 Comments

Throughout this two-year global COVID-19 nightmare, one thing that has been sorely lacking is access to testing. “Flu-like symptoms” covers a lot of ground, and knowing if a sore throat is just a sore throat or something more is important enough that we’ve collectively plowed billions into testing. Unfortunately, the testing infrastructure remains unevenly distributed, which is a problem this backpack SARS-CoV-2 testing lab aims to address.

The portable lab, developed by [E. Emily Lin] and colleagues at the Queen Mary University of London, uses a technique called LAMP, for loop-mediated isothermal amplification. LAMP probably deserves an article of its own to explain the process, but suffice it to say that like PCR, LAMP amplifies nucleic acid sequences, but does so without the need for expensive thermal cycling equipment. The kit contains a microcentrifuge that’s fashioned from an e-waste hard drive, a 3D printed rotor, and an Arduino to drive the motor and control the speed. The centrifuge is designed to run on any 12 VDC source, meaning the lab can be powered by a car battery or solar panel if necessary. Readout relies on the trusty Mark I eyeball and a pH-indicating buffer that changes color depending on how much SARS-CoV-2 virus was in the sample.

Granted, the method used here still requires more skill to perform than a simple “spit on a stick” rapid antigen test, and it’s somewhat more subjective than the “gold standard” quantitative polymerase chain reaction (qPCR) assay. But the method is easily learned, and the kit’s portability, simple design, and low-cost construction could make it an important tool in attacking this pandemic, or the next one.

Thanks to [Christian Himmler] for the tip.

1960s Stereo Console Gets An Upgrade

February 5, 2022 by Chris Lott 20 Comments

Faced with an old console stereo from the 1960s that was barely functional, [Sherman Banks] aka W4ATL decided to upgrade its guts while keeping its appearance as close to the original as possible. This stereo set is a piece of mahogany furniture containing an AM/FM stereo receiver and an automatic turntable from JCPenny’s Penncrest line. As best [Sherman] can determine, it is most likely a 1965 model. The old electronics were getting more and more difficult to repair and the tuner was drifting off-station every 15 minutes. He didn’t want to throw it away, so he decided to replace all the innards.

The first thing was to tear out the old electronics while retaining the chassis proper. The new heart of the entertainment center is a modern Denon AV stereo receiver. This unit can be controlled over Ethernet, has a radio tuner, inputs for SiriusXM and a turntable, and supports Bluetooth streaming. [Sherman] next replaced the 1965 turntable, and then turned his attention to connecting up the controls and indicators.

The potentiometers were replaced with equivalent ones of lower resistance, the neon stereo indicator was replaced with an LED, but the linear tuning dial proved to be a nearly two month challenge and resulted in a cool hack. In brief, he connected an optical rotary encoder to the tuning knob and used a stepper motor with a linear actuator to control the dial indicator. All this is controlled from an Arduino Mega 2560 with three shields for I/O and LAN. But there was still one remaining issue — without vacuum tubes to warm up, the radio would play immediately after power-on. [Sherman] fixed that by programming the Arduino to slowly ramp up the volume at the same rate as the original tube receiver. And finally, he installs a small HDMI monitor in the corner to display auxiliary information and metadata from the Denon receiver.

Check out the videos below the break. We wrote about a couple of similar conversions in the past: this one from 2018 was also a Penncrest, and from last year this COVID isolation project that emphasized the addition of a new liquor cabinet.

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Arduino Activated Automotive Aerodynamic Apparatus Is… (Spoiler Alert!)

February 3, 2022 by Ryan Flowers 8 Comments

Sometimes a great hack is great for no other reason than that it’s fun, and [Michael Rechtin]’s DIY Active Aero Spoiler and Air Brake certainly qualifies as a fun hack. This is a mod designed to live in a world where looks are everything, stickers add horsepower, and a good sound system is more important than good wheel alignment. Why is that? Because like the switch that exists only to activate the mechanism that turns it off, the DIY Active Aero Spoiler and Air Brake seen below is almost completely useless. So to understand its allure, we must understand its inspiration.

For a few decades now, luxury sports car manufacturers have been adding active aerodynamic components to their vehicles. For example, several Porsche models feature adaptive spoilers that adjust to driving conditions. Super cars such as the Bugatti Veyron have spoilers that flip up at high angles during braking to increase drag and reduce braking distance. All of these features are sadly missing from the average two or four door family-car-turned-wannabe-track-fiend. Until now!

[Michael] has created a new active spoiler for every mall-bound muffler-challenged hand me down. The build starts with a CNC cut foam wing which is covered with fiberglass, Bondo (an automotive necessity) and some faux carbon fiber for that go-fast feel. An Arduino, IMU, two servos, and a battery pack detect deceleration and automatically increase the spoiler angle just like the big boys, but without needing any integration into the vehicles systems. Or bolts, for that matter.

It’s unlikely that the braking force is enough to slow down the vehicle though, given that it’s not enough to pop the suction cups holding it to the trunk lid. But does it have the “wow” factor that it was designed to induce? Spoiler Alert: It does!

As it turns out, this isn’t the first adjustable spoiler featured here at Hackaday, and this adjustable spoiler on a car that’s made for actual racing is quite interesting.

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Meowing Box Will Befuddle Your Friends

January 29, 2022 by Lewin Day 11 Comments

If you don’t own a cat, hearing the sound of one meowing from somewhere in the house probably comes as quite a shock. The Cat Prank box built by [Reuben] promises to deliver such hilarity with aplomb.

The idea is simple: hide the Cat Prank box in a cupboard or other space in a friend’s house, and it will meow from its secret location. When found, either the light sensor or motion sensor will trigger the yowling of an angry feline, with hopefully startling effects.

An Arduino Mini is the brains of the operation, paired with an XY-V17B sound module which plays the required animal wailings. There’s also a 433 MHz radio module that lets the prankster trigger meowing via remote control.

Code is available for those wishing to build their own. We’d love to see a mod with a time delay built in, so the device could be hidden and left to start meowing at some later date when the prankster is far away.

Similar work has graced these pages before, like the devilishly fiendish OpenKobold design. Just make sure your friends are receptive to such jokes before you go ahead and invest time and hardware in the prank!

A wooden xylophone with electronic contraptions for robotic playback

Robotic Xylophone Makes Music With MIDI Magic

January 27, 2022 by Chris Wilkinson 8 Comments

The MIDI format has long been used to create some banging electronic music, so it’s refreshing to see how [John P. Miller] applied the standard in his decidedly analog self-playing robotic xylophone.

Framed inside a fetching Red Oak enclosure, the 25-key instrument uses individual solenoids for each key, meaning that it has no problem striking multiple bars simultaneously. This extra fidelity really helps in reproducing the familiar melodies via the MIDI format. The tracks themselves can be loaded onto the device via SD card, and selected for playback with character LCD and rotary knob.

The software transposes the full MIDI music spectrum of a particular track into a 25-note version compatible with the xylophone. Considering that a piano typically has 88 keys, some musical concessions are needed to produce a recognizable playback, but overall it’s an enjoyable musical experience.

Perhaps most remarkable about this project is the documentation. If you want to build your own, everything you need to know is available online, and the no-solder approach makes this project very accessible. Most of the write-up happened some years ago, and we’re really interested to see what improvements have been made since.

The robotic xylophone is reminiscent of these automatic tubular bells from some time ago. These musical hacks can be particularly inspiring, and we can’t wait to see more.

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