The first obstacle was to find a satisfactory way to play back audio. In the past, I have had some success using PWM pins, but this needs a low-pass filter as well as an amplifier, and the quality of audio was never as good as I’d hoped for. The other alternative is to use one of the many HATs available, but these come at a price as they are normally aimed at more serious quality of audio. I wanted to keep the cost down, so these were excluded as an option. The other option was to use a mono I2S 3W amplifier breakout board – MAX98357A from Adafruit – which is extremely
simple to use. As the BBC didn’t start broadcasting stereo commercially until the late 1950s, this was also very apt for the radio (which only has one speaker).
Connecting up this board is very easy – it just requires three GPIO pins, power, and the speaker. For this, I just soldered some female jumper leads to the breakout board and connected them to the header pins of the Raspberry Pi Zero. There are detailed instructions on the Adafruit website for this which basically entails running their install script.
Once the install scripts and mpg123 player are installed with a speaker connected, the Raspberry Pi Zero immediately started playing some very nice quality audio through the on-board 3W amplifier – and it is certainly loud enough to emulate a radio.
8-6-2021 (August 6, 2021) is the Snakiest day of the year and it’s also this year’s CircuitPython Day! The day highlights all things CircuitPython and Python on Hardware. See you there!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.