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.

Atmel powers this 2D-Lux smart LED disk (SLEDD)

NliteN has unveiled the 2D-Lux Smart LED Disk (SLEDD), a dimmable 60W-incandescent-replacement LED smart “bulb” with an Atmel AVR microcontroller (ATtiny85), USB interface and hardware-expansion pins. Currently on IndieGoGo, the Atmel-powered SLEDD allows backers to easily adjust the 2D-Lux by running various light-bulb control apps, including smartphone control.

“The low power sleep modes found in Atmel’s AVR, as well as its wide voltage operating range, has allowed NliteN to eliminate expensive AC to DC power supplies, as well as eliminating the need for large electrolytic capacitors which are a huge reliability and lifetime concern in Solid State Lighting today,” explained Andreas Eieland, Atmel’s Sr. Product Marketing Manager of Standard Microcontrollers. “The AVR’s high processing throughput allows inexpensive, direct, USB interfacing to the AVR, facilitating the ability of an owner to download apps by simply attaching a PC’s USB cable to the integrated connector on the bulb.”

In addition, Atmel’s low noise, high precision, on-chip analog to digital converters enabled NliteN designers to measure system temperatures to prevent system overheating in enclosed fixtures – as well as monitor AC power waveforms and implement a planned low-cost powerline receiver communications capability similar to the BSR X10.

It should also be noted that users can add shields, or plug-in circuit board modules to SLEDD, facilitating additional hardware functions via microphones (clap on, clap off, clap dim, loudness sensitive brightness, etc), motion sensors, Zigbee, Bluetooth, WiFi, Linux web appliance and battery-backed-up clock-calendars.

Interested in learning more about the Atmel-powered 2D-Lux Smart LED Disk? Be sure to check out the project’s official page on IndieGoGo.

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.