Building a pseudo-theremin with Atmel and Adafruit

The theremin, originally known as the ætherphone/etherphone, thereminophone or termenvox/thereminvox, is an early electronic musical instrument controlled without physical contact by the thereminist (performer). According to Wikipedia, the instrument is named after the westernized name of its Russian inventor, Léon Theremin, who patented the device in 1928.

Inspired by the musical instrument, the Adafruit crew went ahead and designed a pseudo-theremin built around an Atmel-powered Arduino Uno (ATmega328) – combining the board with a light-sensitive cadmium sulfide (CdS) photocell to make a light responsive music machine.

The original pseudo-theremin project was recently updated by Mike Barela, who swapped the Uno for the Atmel-powered Trinket or Gemma.

“Changes in light intensity on the photocell will change the pitch of a note on the piezo speaker as you wave your hand in front of the cell,” Barela explained. “While not a true theremin (which uses changes in a circuit’s reactance), this project is much simpler to build.”

As previously discussed on Bits & Pieces, the Gemma is a tiny wearable platform board packed in a 1″ diameter package. The device – powered by Atmel’s versatile Attiny85 – is easily programmable with an Arduino IDE over USB. Similarly, Adafruit’s Trinket, a tiny microcontroller board, is also built around Atmel’s ATtiny85.

An Atmel cyberpunk jacket for your steampunk goggles

Recently, the AdaFruit crew designed a pair of Atmel-powered goggles dubbed “Kaleidoscope Eyes” for cyberpunks, steampunks and yes, even Daft Punks. Today we’re going to be taking a closer look at a Flora GPS Jacket that can be tastefully paired with the futuristic AdaFruit goggles for a full cyberpunk/steampunk fashion ensemble.

The GPS Jacket – designed by AdaFruit’s Becky Stern – is built around Flora, a wearable electronics platform powered by Atmel’s Atmega32u4 MCU.

“Make your coat react to your location with color-changing LEDs! The Flora GPS Jacket tracks your coordinates and then pulses the lights around the collar when you reach your destination,” Stern wrote in a recent post. “[You can] change the waypoints and range in the provided project code to make your garment light up near your favorite coffee shops or the perfect picnic spot.”

Key components for the GPS Jacket? A Flora GPS Starter Pack (includes a Flora main board, Flora GPS and 8 Flora pixels), battery holder (3xAAA w/JST recommended), USB cable (A to mini B), sewable battery holder coin-cell battery (optional for faster GPS fix), conductive thread, multimeter, alligator clips and snaps (optional).

The project begins by chaining 8 pixels together around the collar and attaching the GPS to 3.3v, TX, RX, and ground. A 3xAAA battery holder hides in a pocket and extends through a seam to plug into the JST port on the Flora.

Interested in learning more? Full instructions for designing AdaFruit’s GPS Jacket can be found on Becky Stern’s detailed tutorial.

The Halo 3-Arduino connection

Adafruit forum member JoshuaKane and fellow Maker Sean Bradley have designed an impressive Halo 3 Orbital Drop Shock Trooper (ODST) costume, complete with an energy sword.

“I wanted to make the sword something that would literally make folks stop in their tracks and take notice at a convention. [So] I turned to the [ATmega32u4-powered] Arduino Micro and some accessories developed at Adafruit,” JoshuaKane explained in a recent forum post.

“The full idea is to give the impression of a pulsing energy sword. The perfect item to light this sword are the NeoPixel strips (60 LEDs per meter). The complete package is a sword that would light up when you turned it on, and play a sound indicating that it was switched on. Think Star Wars light saber.”

Additional components used in the Halo 3 energy sword project? The ADXL345 (3-axis accelerometer) which is tasked with detecting motion and trigger a sound event via the VS1053 (MP3 decoder) breakout board. There are also 2x liPo 2600mAh batteries hooked in parallel through a UBEC, generating a constant, clean 5v for the LEDs and controller.

As previously discussed on Bits & Pieces, the Arduino Micro is a microcontroller board based on Atmel’s ATmega32u4. Developed by Arduino and Adafruit, the board boasts 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHzcrystal oscillator, a micro USB connection, an ICSP header and  reset button. The board contains everything needed to support the microcontroller – simply connect it to a computer with a micro USB cable to get started. It also offers a form factor that enables it to be easily placed on a breadboard.

It should be noted that the Micro is similar to the Arduino Leonardo as the ATmega32u4 offers built-in USB communication, eliminating the need for a secondary processor. This allows the Micro to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.

Atmel goes cyberpunk with Adafruit

Cyberpunk novels and films are typically set in post-industrial dystopias characterized by extraordinary cultural ferment and the use of technology in ways never anticipated by its original creators. As William Gibson aptly noted in Burning Chrome, “the street finds its own uses for things.”

Recently, the AdaFruit crew designed a pair of goggles for cyberpunks, steampunks and yes, Daft Punks. Officially dubbed “Kaleidoscope Eyes,” key components for the headware include NeoPixel rings, an Atmel-powered (ATtiny85) Trinket (or Atmel-powered Gemma) and a battery (lithium-polymer or 3x AA battery case). Heat-shrink tubing is recommended for insulating the wire connections, as is diffuser lenses for the goggles which help soften the light from LEDs. The latter can simply be cut from paper or fashioned with white acrylic.

“This is a soldering project, albeit a small one. You will need the common soldering paraphernalia of a soldering iron, solder, wire (20 to 26 gauge, either stranded or solid) and tools for cutting and stripping wire,” AdaFruit’s Phillip Burgess explained in a detailed tutorial on the subject.

“You’ll need some method of securing the electronics inside the goggles. Hot-melt glue (with a glue gun) works well for this. Watch your fingers! Tape could be used for a quick and temporary setup. Some steps require perseverance. You will need to provide your own; we do not sell patience in the shop.”

Burgess also confirmed that Makers can swap an Atmel-powered Gemma for the Atmel-powered Trinket.

“You won’t need the extra JST cable for the LiPo battery — Gemma has that plug built-in,” he said. “[Remember], the board is a bit wider and might be more challenging to fit, but one option is to show it off rather than conceal it, mounting the board on the outside of the goggles near one temple. Geek pride!”

Interested in learning more about building “Kaleidoscope Eyes” with Adafruit and Atmel? You can check out Adafruit’s detailed tutorial here, although Burgess warns the project is quite challenging.

“Small parts are used in confined spaces, and special tools and techniques are used. While not overtly dangerous, there’s still some potential for damage or injury,” he added. [So be sure to] read through everything first to decide if you really want to tackle this. Young makers should read through with a parent to help decide – [and] we [certainly do] have other wearable electronics projects that are less daunting.”

Adafruit’s Gemma has Atmel under the hood

Adafruit has debuted Gemma, a tiny wearable platform board packed in a 1″ diameter package. The device – powered by Atmel’s versatile Attiny85 – is easily programmable with an Arduino IDE over USB.

“We wanted to design a microcontroller board that was small enough to fit into any project, and low cost enough to use without hesitation,” Adafruit’s Limor Fried (aka LadyAda) explained in a recent blog post. “Gemma is perfect for when you don’t want to give up your Flora and aren’t willing to take apart the project you worked so hard to design. It’s our lowest-cost sewable controller!”

Fried described the Attiny85 as a “fun processor” because despite being so small, the device boasts 8K of flash and 5 I/O pins, including analog inputs and PWM ‘analog’ outputs.

“We designed a USB bootloader so you can plug it into any computer and reprogram it over a USB port just like an Arduino (it uses 2 of the 5 I/O pins, leaving you with 3),” Fried continued. “In fact we even made some simple modifications to the Arduino IDE so that it works like a mini-Flora. Perfect for small and simple projects – the Gemma will be your go-to wearable electronics platform.”

In addition to Atmel’s ATtiny85, key hardware specs include:

• 1.1″ / 28mm diameter and 0.28″ / 7mm thick.
• Easy-to-sew or solder pads for embedding in wearable projects.
• 8K of flash, 512 byte of SRAM, 512 bytes of EEPROM.
• Internal oscillator runs at 8MHz.
• Ultra low power, only 9 mA while running.
• USB bootloader with LED indicator programmable with the Arduino IDE
• Mini-USB jack for power and/or USB uploading
• Rugged and foolproof bootloader process
• ~5.25K bytes available for use (2.75K taken for the bootloader)
• On-board 3.3V or 5.0V power regulator with 150mA output capability and ultra-low dropout.
• Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
• Power with either USB or external output (such as a battery) – it’ll automatically switch over
• On-board green power LED and red pin #1 LED; reset button for entering the bootloader or restarting the program.
• 3 GPIO – The 3 independent IO pins have 1 analog input and 2 PWM output as well.
• Hardware I2C capability for breakout and sensor interfacing.

Interested in learning more about Adafruit’s Gemma? You can check out LadyAda’s detailed Gemma tutorial here.

Atmel’s ATtiny85 powers this Tap Tempo Trinket

Last week, Adafruit launched the Trinket, a tiny microcontroller (MCU) board built around Atmel’s versatile ATtiny85. This week, Adafruit’s Phillip Burgess is showcasing the Tap Tempo Trinket, a DIY beats-per-minute calculator project powered by Atmel’s ATtiny 85 and the Trinket board.

“This beats-per-minute calculator is a quick and easy project,” Burgess explained in a recent Adafruit post. “You tap the button in time with music [and the] Trinket reports the corresponding beats-per-minute.”

Required components include:

• Adafruit Trinket (either the 5V or 3.3V variety)
• 7-segment LED Display Backpack (any color, 0.56″ size, not 1.2″)
• Momentary “normally open” pushbutton
• Breadboard, jumper wires, USB cable (A to mini B)

“If this is your first time using Trinket, work through the Introducing Trinket guide first; you need to customize some settings in the Arduino IDE first,” Burgess continued. “Once you have it up and running, you’ll then install the following libraries: TinyWireM (a Trinket-compatible alternative to the Arduino Wire library), Adafruit_LEDBackpack and Adafruit_GFX (required by Adafruit_LEDBackpack).”

According to Burgess, the simple DIY project is one where Trinket really shines, with the largest section of the code simply flashing “TAP BEAT” at startup.

“Button input is debounced, time between button taps is then calculated using the micros() timer, and BPM is figured by dividing 600,000,000 (10X the number of microseconds in 1 minute) by this time interval. The 10X figure is just so we can look extra geeky by then adding a decimal point,” he added.

Be sure to check out Adafruit’s detailed tutorial here for additional information on how to build your own Tap Tempo Trinket.

Adafruit launches ATtiny85-powered Trinket

Adafruit has launched the Trinket, a tiny microcontroller board built around Atmel’s ATtiny85.

“We wanted to design a microcontroller board that was small enough to fit into any project – and low cost enough to use without hesitation,” Adafruit’s Limor Fried (aka LadyAda) explained.

“[It is] perfect for when you don’t want to give up your expensive dev-board and you aren’t willing to take apart the project you worked so hard to design.”

Fried describes the Attiny85 as a “fun processor,” because despite being so small, it boasts 8K of flash and 5 I/O pins – including analog inputs and PWM ‘analog’ outputs.

“We designed a USB bootloader so you can plug it into any computer and reprogram it over a USB port just like an Arduino,” Fried continued. “In fact we even made some simple modifications to the Arduino IDE so that it works like a mini-Arduino board. You can’t stack a big shield on it but for many small and simple projects the Trinket will be your go-to platform.”

There are currently two versions of the Trinket: 3V and 5V. According to LadyAda, both work the same but have different operating logic voltages.

“Use the 3V one to interface with sensors and devices that need 3V logic, or when you want to power it off of a LiPo battery. The 3V version should only run at 8 MHz. Use the 5V one for sensors and components that can use or require 5V logic, [as] the 5V can run at 8 MHz or at 16MHz by setting the software-set clock frequency,” she added.

Key specs include:

• ATtiny85 on-board, 8K of flash, 512 byte of SRAM, 512 bytes of EEPROM.
• Internal oscillator runs at 8MHz, but can be doubled in software for 16MH.z
• USB bootloader with a nice LED indicator looks just like a USBtinyISP and can be programmed with AVRdude (with a simple config modification) and/or the Arduino IDE (with a few simple config modifications).
• Mini-USB jack for power and/or USB uploading.
• On-board 3.3V or 5.0V power regulator with 150mA output capability and ultra-low dropout.
• Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
• Power with either USB or external output (such as a battery) – it’ll automatically switch over.
• On-board green power LED and red pin #1 LED.
• Reset button for entering the bootloader or restarting the program. No need to unplug/replug the board for reset or update.
• 5 GPIO – two shared with the USB interface. The three independent IO pins have one analog input and two PWM output as well. The two shared IO pins have two more analog inputs and one more PWM output.
• Hardware I2C / SPI capability for breakout & sensor interfacing.
• Mounting holes.

The Trinket can be purchased here for $7.95 here, while an extensive guided tour is available here.

Atmel lights up these LED sneakers

Known as “FLORA,” Adafruit’s wearable electronics platform is built around Atmel’s Atmega32u4 MCU. The microcontroller boasts built-in USB support, eliminating the need for pesky special cables and extra parts.

According to Adafruit’s Limor Fried, FLORA is extremely “beginner-friendly.” Indeed, the device is difficult to accidentally destroy by connecting a battery backwards, thanks to a polarized connector and protection diodes. Meanwhile, an onboard regulator ensures even connecting a 9V battery won’t result in damage or tears.

As previously discussed on Bits & Pieces, numerous Makers are using the versatile FLORA to design a wide range of creations, including the Adafruit team itself which recently debuted a pair of LED sneakers dubbed “Firewalker,” courtesy of Becky Stern and Phillip Burgess (aka Paint Your Dragon).

Key project specs include two Atmel-powered FLORA main boards, velostat, two meters NeoPixel 60-LED strip in black or white and yes, a pair of sneakers. You can read more about Adafruit’s latest project here on the official Firewalker page.

Video: The Arduino-based NeoPixel Compass

The NeoPixel Compass – powered by an Arduino Uno (Atmel ATmega328) – features 16 ultra bright smart LED NeoPixels arranged in a circle with 1.75″ (44.5mm) outer diameter.

How does it work? As you can see in the video above, the rings are “chainable,” so you simply connect the output pin of one to the input pin of another.

This means only one microcontroller pin is necessary to control as many (rings) as you chain together. Plus, each LED is addressable as the driver chip is inside the LED.

According to the Adafruit blog, each one has ~18mA constant current drive – so the color will be still be consistent even if the voltage varies. In addition, no external choke resistors are required, making the design slim. Oh, and yes, the entire device can be powered with 5VDC (4-7V works).

Required components include:

• NeoPixel ring
• Compass module
• Arduino Uno

Atmel-powered FLORA measures your beating heart

Earlier this month, we took a closer look at “FLORA,” Adafruit’s wearable electronics platform powered by Atmel’s Atmega32u4 MCU. The microcontroller boasts built-in USB support, eliminating the need for pesky special cables and extra parts.

Unsurprisingly, numerous Makers are currently using Adafruit’s FLORA to design a wide range of creations, a fact that has caught the eye of the folks at element14. To be sure, the Newark Corporation recently issued a challenge to engineers and Makers to develop their own piece of wearable technology. The platform of choice for the contest? Adafruit’s versatile FLORA.

Today, Adafruit’s very own Becky Stern is showcasing a wearable badge designed to display the beat of your heart. The project – based on FLORA – uses the Polar heart rate sensor which you wear around your ribcage as it wirelessly transmits heart beats to the receiver chip included in Adafruit’s educational starter pack.

As seen in the video above, the badge can be worn on your clothes or bag, as it is held in place by a magnetic pin back. Required hardware items for this project include:

• Polar Wireless heart sensor educational starter pack
• FLORA main board
• 150 mAh lipoly battery (with charger)
• Eight FLORA NeoPixels or 8×8 LED matrix w i2c backpack
• Magnetic pin back
• Sugru
• Thin stranded wire
• Double-stick tape or foam

Want to wear your beating heart with FLORA? The complete Heart Rate Badge guide is available here.