This tiny audio amplifier is based on the Texas Instruments TPA2005D1. Its efficient class-D operation means low heat and long battery life. It can drive an 8-Ohm speaker at up to 1.4 Watts; it won’t shake a stadium, but it will provide plenty of volume for your audio projects.

The fully-differential inputs are safe for floating audio signals such as from our MP3 Shield, and can also be connected to ground-referenced signals as well. A shutdown input is provided to save power when the amplifier is not being used, and a solder jumper and header are provided to connect a volume-control potentiometer (not included).

Note: The amplifier’s class-D design outputs a 250kHz PWM-like signal that is restored to an analog voltage in the speaker’s coil. This is what makes the amplifier so efficient, but because of the switching frequency, you should keep the amplifier as close to the speaker as possible to minimize possible interference.

Features

Extremely efficient class-D amplifier

1.4W into 8 Ohms

2.5V to 5.5V supply

Fully differential audio inputs, can be ground-referenced as well

Shutdown input with pullup and LED-follows-shutdown circuitry

PTH pads provided to change gain resistors if desired (see datasheet for details)

Solder jumper and header allow addition of a 10k volume control potentiometer (not included)

The SparkFun Sound Detector is a small and very easy to use audio sensing board with three different outputs. The Sound Detector not only provides an audio output, but also a binary indication of the presence of sound, and an analog representation of its amplitude. The 3 outputs are simultaneous and independent, so you can use as many or as few as you want at once.

The envelope output allows you to easily read amplitude of sound by simply measuring the analog voltage. Gain can be adjusted with a through-hole resistor, to change the threshold of the binary (gate) output pin as well. Check the hookup guide below for more information about setting gain.

Each of the three output signals is present on the .1" pin-out at the edge of the board. They are active simultaneously. If you aren’t using one in your particular application, simply leave that pin disconnected.

Get Started with the SparkFun Sound Detector Guide

The SparkFun MP3 Player Shield is an awesome MP3 decoder with the capabilities of storing music files onto a run-of-the-mill microSD card, thus giving you the ability toadd music or sound effects to any project. With this board you can pull MP3 files from an microSD card and play them using only one shield, effectively turning any Arduino into a fully functional stand-alone MP3 player! The MP3 Shield utilizes the VS1053B MP3 audio decoder IC to decode audio files. The VS1053 is also capable of decoding Ogg Vorbis/MP3/AAC/WMA/MIDI audio and encoding IMA ADPCM and user-loadable Ogg Vorbis.

The VS1053 receives its input bitstream through a serial input bus (SPI). After the stream has been decoded by the IC, the audio is sent out to both a 3.5mm stereo headphone jack, as well as a 2-pin 0.1" pitch header.

This shield comes populated with all components as shown in the images and schematic; but it does not come with headers installed. We recommend the Arduino R3 Stackable Header Kit.

Features

3.5mm audio out jack

0.1" spaced header for speaker out

microSD card slot

Add an ear to your project with this well-designed electret microphone amplifier. This fully assembled and tested board comes with a 20-20KHz electret microphone soldered on. For the amplification, we use the Maxim MAX4466, an op-amp specifically designed for this delicate task! The amplifier has excellent power supply noise rejection, so this amplifier sounds really good and isn't nearly as noisy or scratchy as other mic amp breakouts we've tried!This breakout is best used for projects such as voice changers, audio recording/sampling, and audio-reactive projects that use FFT. On the back, we include a small trimmer pot to adjust the gain. You can set the gain from 25x to 125x. That's down to be about 200mVpp (for normal speaking volume about 6" away) which is good for attaching to something that expects 'line level' input without clipping, or up to about 1Vpp, ideal for reading from a microcontroller ADC. The output is rail-to-rail so if the sounds gets loud, the output can go up to 5Vpp!Using it is simple: connect GND to ground, VCC to 2.4-5VDC. For the best performance, use the "quietest" supply available (on an Arduino, this would be the 3.3V supply). The audio waveform will come out of the OUT pin. The output will have a DC bias of VCC/2 so when its perfectly quiet, the voltage will be a steady VCC/2 volts (it is DC coupled). If the audio equipment you're using requires AC coupled audio, place a 100uF capacitor between the output pin and the input of your device. If you're connecting to an audio amplifier that has differential inputs or includes decoupling capacitors, the 100uF cap is not required.The output pin is not designed to drive speakers or anything but the smallest in-ear headphones - you'll need an audio amplifier (such as our 3.7W stereo amp) if you want to connect the amp directly to speakers. If you're connecting to a microcontroller pin, you don't need an amplifier or decoupling capacitor - connect the OUT pin directly to the microcontroller ADC pin.For audio-reactive Arduino projects, we suggest using an FFT driver library (such as the one in this library) which can take the audio input and 'translate' it into frequencies. Also, check out this awesome Voice Changer project that uses this mic and an Adafruit Wave Shield!

If you're using with CircuitPython, this audio-reactive pendant project is pretty easy and works great with any CircuitPython board.

The Teensy is a breadboard-friendly development board with loads of features in a, well, teensy package. Each Teensy 3.1 comes pre-flashed with a bootloader so you can program it using the on-board USB connection: No external programmer needed! You can program for the Teensy in your favorite program editor using C or you can install the Teensyduino add-on for the Arduino IDE and write Arduino sketches for Teensy!

The processor on the Teensy also has access to the USB and can emulate any kind of USB device you need it to be, making it great for USB-MIDI and other HID projects. The 32 bit processor brings a few other features to the table as well, such as multiple channels of Direct Memory Access, several high-resolution ADCs and even an I2S digital audio interface! There are also 4 separate interval timers plus a delay timer! Oh yeah, and all pins have interrupt capability. Also, it can provide system voltage of 3.3V to other devices at up to 250mA.

All of this functionality is jammed into a 1.4 x 0.7 inch board with all headers on a 0.1" grid so you can slap in on a breadboard and get to work! The Teensy 3.2 adds a more powerful 3.3 volt regulator, with the ability to directly power an ESP8266 Wifi, WIZ820io Ethernet, and other 3.3V add-on boards that require a little more power. Additionally, if it is used within the Teensy 3.1 limits of operation, the Teensy 3.2 and 3.1 are interchangeable!

Note: This does not come with a USB cable, please check below for an appropriate one.

Features

32 bit ARM Cortex-M4 72 MHz CPU (M4 = DSP extensions)

256K Flash Memory, 64K RAM, 2K EEPROM

21 High Resolution Analog Inputs (13 bits usable, 16 bit hardware)

34 Digital I/O Pins (5V tolerance on Digital Inputs)

12 PWM outputs

7 Timers for intervals/delays, separate from PWM

USB with dedicated DMA memory transfers

3 UARTs (serial ports)

SPI, I2C, I2S,CAN Bus, IR modulator

I2S (for high quality audio interface)

Real Time Clock (with user-added 32.768 crystal and battery)

16 DMA channels (separate from USB)

Touch Sensor Inputs

1.4 x 0.7" (~35 x 18 mm)

This audio adapter lets you easily add high quality 16 bit, 44.1 kHz sample rate (CD quality) audio to your projects with a Teensy 3.2, 3.5 or 3.6. It supports stereo headphone and stereo line-level output, and also stereo line-level input or mono microphone input.The audio chip connects to Teensy v3 using 7 signals. The I2C pins SDA and SCL are used to control the chip and adjust parameters. Audio data uses I2S signals, TX (to headphones and/or line out) and RX (from line in or mic), and 3 clocks, LRCLK (44.1 kHz), BCLK (1.41 MHz) and MCLK (11.29 MHz). All 3 clocks are created by Teensy 3.1. The SGTL5000 chip operates in "slave mode", where all its clock pins are inputs.

As of February 23rd, 2015 we are shipping an updated version with a few minor changes.This product does NOT include a Teensy, it's just the audio adapter!

Sometimes we wonder if robotics engineers ever watch movies. If they did, they'd know that making robots into slaves always ends up in a robot rebellion. Why even go down that path? Here at Adafruit, we believe in making robots our friends!

So if you find yourself wanting a companion, consider the robot. They're fun to program, and you can get creative with decorations.

With that in mind, we designed Crickit - That's our Creative Robotics & Interactive Construction Kit. It's an add-on to our popular Feather ecosystem that lets you #MakeRobotFriend using CircuitPython, MakeCode (coming soon), or Arduino.

Plug in any Feather mainboard you want into the center, and you're good to go! The Crickit is powered by seesaw, our I2C-to-whatever bridge firmware. So you only need to use two I2C data pins to control the huge number of inputs and outputs on the Crickit. All those timers, PWMs, sensors are offloaded to the co-processor.

The only thing that is not managed by seesaw is the audio output. We provide a small jumper you can solder to connect the audio amplifier to the first analog pin. On our Feather M0's this is a true analog output (DAC) and you can play audio clips with CircuitPython or Arduino. Other Feathers may not have a DAC! In that case, you can solder a wire to jumper the audio amp to a PWM pin.

You get to use all the non-I2C signal pins on your feather and get a boat-load of extra in/out pins, motor controllers, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your Feather so you can still use all the goodies, including stacking FeatherWings on top. But now you have a robotics playground as well.

You get:

4 x Analog or Digital Servo control, with precision 16-bit timers

2 x Bi-directional brushed DC motor control, 1 Amp current limited each, with 8-bit PWM speed control (or one stepper)

4 x High current "Darlington" 500mA drive outputs with kick-back diode protection. For solenoids, relays, large LEDs, or one uni-polar stepper

4 x Capacitive touch sensors with alligator-pads

8 x Signal pins, digital in/out or analog inputs

1 x NeoPixel driver with 5V level shifter - The NeoPixels are buffered and controlled by the seesaw chip

1 x Class D, 4-8 ohm speaker, 3W-max audio amplifier - the audio input pin is available as a solder-able pad for your configuration, you can connect it to your Feather's DAC or PWM output as you desire.

All are powered via 5V DC, so you can use any 5V-powered servos, DC motors, steppers, solenoids, relays etc. To keep things simple and safe, we don't support mixing voltages, so only 5V, not for use with 9V or 12V robotic components.

Please note this robot board does not require any soldering but you will need a power supply and a Feather to go along with the Crickit, and these are not included! We recommend also purchasing:

Any one of our Feather mainboards, powered by an ATmega328p, ATmega32u4, ATSAMD21, ATSAMD51, ESP8266, ESP32, WICED, nRF52, etc. All Feathers will work, even ones with SD cards, LoRa radios, WiFi or BTLE modules, etc. Adafruit seesaw only uses I2C and all Feather boards have I2C pins in the same location.

5V 2A power supply

If you're going to be running more than 2 large motors or servos at a time, we recommend a 5V 4A power supply

And of course we have a huge collection of all compatible motors, servos, solenoids, speakers and more in our Crickit category

Since you'll be working with high-current devices, we wanted to have a good solid power supply system that minimizes risk of damage. The power supply has an 'eFuse' management chip that will automatically turn off if the voltage goes above 5.5V or below 3V and has over-current protection at 4A. Every motor driver has kick-back protection. We think this is a nice and durable board for robotics!

Lots more details, schematics, specifications, and code examples in the (still in progress) Adafruit Learn guide.