Planet Arduino

Older hackers will remember that a crystal set radio receiver was often one of the first projects attempted.  Times have changed, but there’s still something magical about gathering invisible signals from the air and listening to the radio on a homemade receiver. [mircemk] has brought the idea right up to date by building an FM radio with an OLED display, controlled with a rotary encoder.

The design is fairly straightforward, based as it is on another project that [mircemk] found on a Chinese site, but the build looks very slick and would take pride of place on any hacker’s workbench. An Arduino Due forms the heart of the project, controlling a TEA5767 module, an SH1106 128×64 pixel OLED display and a rotary encoder. The sound signal is passed through an LM4811 headphone amplifier for private listening, and a PAM8403 Class D audio amplifier for the built-in loudspeaker. The enclosure is made from PVC panels, and accented with colored adhesive tape for style.

It’s easier than ever before to quickly put together projects like this by connecting pre-built modules and downloading code from the Internet, but that doesn’t mean it’s not a worthwhile way to improve your skills and make some useful devices like this one. There are so many resources available to us these days and standing on the shoulders of giants has always been a great way to see farther.

We’ve shown some other radio projects using Arduinos and the TEA5767 IC in the past, such as this one on a tidy custom PCB, and this one built into an old radio case.

Very few of us are ever excited to wake up for the work day, but your mood can still vary from one morning to the next. If you had a rough night, you might wake up feeling melancholy. In that case, the last thing you want to do is hear depressing news on the radio. To help people enter wakefulness, Varenya Raj built a radio called Nidra that tailors the morning news to suit its user’s mood.

Nidra’s design is unusual, in that it doesn’t resemble any radio or alarm clock that you’ve ever seen. Atop its plastic enclosure there are two buttons. The first looks like a pin cushion and the second seems like it could have come from a shaggy, purple marmot. 

If the user is in a bad mood when the alarm goes off, they can slam their hand down onto the cushioned button. Nidra will then play only upbeat news. If the user is in a better mood and can handle the full breadth of the day’s news, they can stroke the purple fur. At the end of the month, a thermal receipt printer pops out statistics on the number of times the user pressed each button.

An Arduino Uno board controls Nidra’s behavior. The cushion has a standard button, while the fur attaches to a force sensitive resistor. Depending on the button pressed, the Arduino sketch tells a connected computer running a Processing sketch to play news from one of two RSS feeds. We imagine that most people will choose the happy news most mornings, but it is always nice to have options. 

The post This radio tailors the morning news to your waking mood appeared first on Arduino Blog.

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.

The radio takes serial (I2C) commands, and the Arduino converts the user interface so that you can control it. The chip comes in several flavors, each with slightly different features. For example, the Si4731 and Si4735 have the RDS/RBDS decoder, and the shortwave mode is available on Si4734 and Si4735. Confused? Page 2 of the programming guide should help. According to [Mirko], he used a 4730, but it still did shortwave with the 4735 library.

Breakout boards with the chip are just a few bucks. It appears the chip has the technical capability to receive single sideband, but it requires a poorly documented patch. It is in recent versions of this library, though.

We always smile when we think that AM is still alive and kicking. Perhaps this is the modern take on that first crystal radio project.

If your young child wants to listen to music, what better way than a beautiful wooden MP3 “radio,” with an array of buttons that select the album? After being inspired by a similar commercial product, Redditor “DerThes” decided to make such a device for a fraction of the cost using an Arduino Uno for control, along with a Music Maker Shield to play off an SD card.

The toddler can select tunes from a grid of 16 input buttons, which are sent to the Uno via a pair of shift registers. There’s also a “parent’s mode” with the ability to choose from up to 99 albums, and a volume knob for… adjusting the volume. 

Finally, the unt features a beautiful enclosure made out of oak and black walnut, with corners softened by dowels to reduce collateral damage “after the player has gone airborne.” More details can be seen on Imgur here and on GitHub.

This is an easy to use MP3 player for small children. I made this for my 2 year old for Christmas. Each of the top 9 buttons will play an album. The black buttons on the bottom are prev – play/pause – next. The player also supports an alternative playback mode that can be activated using a special key combination. That combination will turn the buttons into a 10 digit input matrix allowing playback of up to 99 albums. That way the player can be used by parents as well.

See GitHub for more details, the schematics for the button PCB and the firmware. https://github.com/MichaelThessel/arduino-stoerbert

This is heavily inspired by Hoerbert: https://en.hoerbert.com

When I first saw the Hoerbert at a friends place I wanted it for my child. After I heard of the $400 price tag I knew that I needed to spend 50 hrs and $100 to build my own.

With All Hallow’s Eve looming close, makers have the potential to create some amazing costumes we’ll remember for the rest of the year. If you’re a fan of the hugely addict-*cough* popular game Minecraft, perhaps you’ve considered cosplaying as your favorite character skin, but lacked the appropriate props. [Graham Kitteridge] and his friends have decided to pay homage to the game by making their own light-up Minecraft swords.

These swords use 3D-printed and laser-cut parts, designed so as to hide the electronics for the lights and range finder in the hilt. Range finder? Oh, yes, the sword uses an Arduino Uno-based board to support NewPixels LEDs and a 433Mhz radio transmitter and receiver for ranged detection of other nearby swords that — when they are detected — will trigger the sword to glow. Kind of like the sword Sting, but for friendlies.

All of the files for the parts are available on the project’s Thingverse page and the board setup can be purchased here. If you want to have some fun controlling the real world from inside Minecraft, check out how this fan uses it to turn on lamps in their home.

When [the-rene] was building an escape room, he decided to have a clue delivered by radio. Well, not exactly radio, but rather an old-fashioned radio that lets you tune to a faux radio station that asks a riddle. When you solve the riddle, a secret compartment opens up. [the-rene] says you could have the compartment contain a key or a clue or even a cookie.

The outer case is actually an old radio gutted for this purpose. In addition, a laser cut box and a servo motor form the secret compartment.

The inside of the radio is decidedly modern. A Raspberry Pi B+ and a ATmega328 handle the various functions. Custom PCBs contain the computers and a few other items such as an analog to digital converter (for reading a potentiometer) and an audio amplifier.

The software plays noise until the tuning knob moves near one of six different frequencies. Each frequency can have its own riddle. Of course, the audio is all digital playback, so the frequency is just for effect. There’s no real radio reception going on here at all.

Secret boxes are nothing new around here. At least this puzzle box doesn’t explode.

HamShield lets your Arduino talk to far away people and things using amateur radio bands (Coverage: 136-170MHz, 200-260MHz, 400-520MHz)

HamShield lets your Arduino talk to far away people and things using powerful amateur radio bands! Best of all, the hardware and software is open source!

With the power of Arduino, you can use the HamShield to build and invent amazing things in minutes!

HamShield for Arduino (VHF/UHF transceiver) – [Link]

Morse code used to be widely used around the globe. Before voice transmissions were possible over radio, Morse code was all the rage. Nowadays, it’s been replaced with more sophisticated technologies that allow us to transmit voice, or data much faster and more efficiently. You don’t even need to know Morse code to get an amateur radio license any more. That doesn’t mean that Morse code is dead, though. There are still plenty of hobbyists out there practicing for the fun of it.

[Dan] decided to take a shortcut and use some modern technology to make it easier to translate Morse code back into readable text. His project log is a good example of the natural progression we all make when we are learning something new. He started out with an Arduino and a simple microphone. He wrote a basic sketch to read the input from the microphone and output the perceived volume over a Serial monitor as a series of asterisks. The more asterisks, the louder the signal. He calibrated the system so that a quiet room would read zero.

He found that while this worked, the Arduino was so fast that it detected very short pulses that the human ear could not detect. This would throw off his readings and needed to be smoothed out. If you are familiar with button debouncing then you get the idea. He ended up just averaging a few samples at a time, which worked out nicely.

The next iteration of the software added the ability to detect each legitimate beep from the Morse code signal. He cleared away anything too short. The result was a series of long and short chains of asterisks, representing long or short beeps. The third iteration translated these chains into dots and dashes. This version could also detect longer pauses between words to make things more readable.

Finally, [Dan] added a sort of lookup table to translate the dots and dashes back into ASCII characters. Now he can rest easy while the Arduino does all of the hard work. If you’re wondering why anyone would want to learn Morse code these days, it’s still a very simple way for humans to communicate long distances without the aid of a computer.

One day, [Samy]’s best friend [Matt] mentioned he had a wireless doorbell. Astonishing. Even more amazing is the fact that anyone can buy a software defined radio for $20, a small radio module from eBay for $4, and a GSM breakout board for $40. Connect these pieces together, and you have a device that can ring [Matt]’s doorbell from anywhere on the planet. Yes, it’s the ultimate over-engineered ding dong ditch, and a great example of how far you can take practical jokes if you know which end of a soldering iron to pick up.

Simply knowing [Matt] has a wireless doorbell is not enough; [Samy] needed to know the frequency, the modulation scheme, and what the doorbell was sending. Some of this information can be found by looking up the FCC ID, but [Samy] found a better way. When [Matt] was out of his house, [Samy] simply rang the doorbell a bunch of times while looking at the waterfall plot with an RTL-SDR TV tuner. There are a few common frequencies tiny, cheap remote controls will commonly use – 315 MHz, 433 MHz, and 900 MHz. Eventually, [Samy] found the frequency the doorbell was transmitting at – 433.8 MHz.

After capturing the radio signal from the doorbell, [Samy] looked at the audio waveform in Audacity. It looked like this doorbell used On-Off Keying, or just turning the radio on for a binary ‘1’ and off for a binary ‘0’. In Audacity, everything the doorbell transmits becomes crystal clear, and with a $4 434 MHz transmitter from SparkFun, [Samy] can replicate the output of the doorbell.

For the rest of the build, [Samy] is using a mini GSM cellular breakout board from Adafruit. This module listens for any text message containing the word ‘doorbell’ and sends a signal to an Arduino. The Arduino then sends out the doorbell code with the transmitter. It’s evil, and extraordinarily over-engineered.

Right now, the ding dong ditch project is set up somewhere across the street from [Matt]’s house. The device reportedly works great, and hopefully hasn’t been abused too much. Video below.

An Interaction and Industrial Designer studying at Carnegie Mellon University in Pittsburgh tried to re-imagine the way we interact with radios to create a more meaningful relationship between the user and the artefact.

Radios have been around since the 1920s but the devices we have at home haven’t changed much even if they were designed nearly 100 years ago and share similar elements like switches, knobs, sliders.

Yaakov Lyubetsky worked on a prototype of The Experimental Form Radio using Arduino Uno:

When The Experimental Form Radio is laying on a tabletop, it is off. To turn the radio on, you pick it up and slot it onto a wall mount. The radio leverages the elastic qualities of fabric to control stations and volume. To change stations you press lightly and slide your finger along the fabric surface. To change the volume you press firmly into the fabric, and then slide your finger along the deeper cavity in the radio. The video below showcases the interaction.

Requiring the user to pick up and wall mount the radio to turn on creates a ritualistic experience with a very simple feedback mechanism. If the radio is hanging on the wall it’s on, if the radio is laying on a flat surface then it’s off. The visual and auditory feedback allows the user to have a clear understanding of the system state.

Even cooler than the video above is the next one, showing all the “Making of” process to build the wooden piece and the soft interface:

The project uses an Arduino Uno board with a custom circuit made with three independent layers of conductive fabric and conductive thread. Touching together two layers of conductive fabric completes one of twelve circuits that then either change the radio station or the volume.

Take a look at the additional documentation on his website.