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)

This electret capsule microphone is the same one we use in our great microphone amplifier board. It contains a small vibrating element that will output a few milllivolts peak-to-peak. You will need an op-amp to amplify the signal, some chips are designed with the amplifier built in in which case you can wire it up directly.

This is an "omnidirectional" microphone, with -44dB sensitivity, and has 20-20KHz frequency response. You can plug it into a breadboard or perfboard or solder wires to the little wires sticking out the back.

Check out OpenMusicLab's great tutorial on Electret Microphones for a deeper look at how these sensors work. If you need an amplifier board, see our fully-assembled and tested mic amp board with adjustable gain.

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.

Wireless is wonderful, but sometimes you want the strong reliability of a wire. If your Feather board is going to be part of a permanent installation, this Ethernet FeatherWing will let you add quick and easy wired Internet. Just plug in a standard ethernet cable, and run the Ethernet2 library for cross-platform networking. Works with all/any of our Feather boards!

Ethernet is a tried-and-true networking standard. It's supported by every hub and switch, and because there's a physical connection you don't have to noodle around with SSIDs, passwords, authentication schemes or antennas. It works great with any of our Feathers, the WIZ5500 chip communicates over SPI plus a single CS pin. The Arduino Ethernet2 library works great, and within a few seconds after connecting, will do the DHCP setup for you. As a nice extra, the RJ-45 jack has both link and activity lights that will light/blink to let you know the current connection status.

Note this product does not have PoE support, but you can add it by the addition of a PoE splitter. We have a version that provides 5V at 2.4 Amp max into a micro USB connector  just plug in your Feather to be powered over the micro USB connection.

Each order comes with one assembled and tested FeatherWing, plus some header. You will need to solder in the header yourself but its a quick task. Check out our tutorial for code, schematics, files and more!