Overview

In this guide we'll take a few simple parts, add some not quite as simple code, and build an adjustable waveform generator (aka frequency generator). Using a rotary encoder push-switch, we'll select one of multiple waveforms, and using the rotation along with the three buttons on the OLED FeatherWing we'll adjust the frequency. We have great guides on the Feather M0 Express and Feather M4 Express as well as the OLED Featherwing to get you up to speed on this hardware.

A small speaker is useful to listen to the signal as a functional test. There's a nice one listed below but there are others; any 8 ohm speaker will work.  The signal isn't very strong, so stick with a small one. You can easily power this by the USB port, but a LiPo battery will let you use it on it's own, untethered from a computer.

This project will work on either a Feather M0 Express or Feather M4 Express. Due to the additional performance and memory of the M4 board, capability of the code can be increased. This is pointed out in the code.

Adafruit Feather M0 Express - Designed for CircuitPython

PRODUCT ID: 3403
We love all our Feathers equally, but this Feather is very special. It's our first Feather that is specifically designed for use with CircuitPython!...
$19.95
IN STOCK

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Adafruit Feather M4 Express - Featuring ATSAMD51

PRODUCT ID: 3857
It's what you've been waiting for, the Feather M4 Express featuring ATSAMD51. This Feather is fast like a swift, smart like an owl, strong like a ox-bird (it's half ox,...
$22.95
IN STOCK

Adafruit FeatherWing OLED - 128x32 OLED Add-on For Feather

PRODUCT ID: 2900
A Feather board without ambition is a Feather board without FeatherWings! This is the FeatherWing OLED: it adds a 128x32 monochrome OLED plus 3 user buttons to...
$14.95
IN STOCK

Rotary Encoder + Extras

PRODUCT ID: 377
This rotary encoder is the best of the best, its a high quality 24-pulse encoder, with detents and a nice feel. It is panel mountable for placement in a box, or you can plug it into a...
$4.50
IN STOCK

Mini Oval Speaker - 8 Ohm 1 Watt

PRODUCT ID: 3923
Hear the good news! This wee speaker is a great addition to any audio project where you need 8 ohm impedance and 1W or less of power. We particularly like...
$1.95
IN STOCK

Other Parts and Tool

Half-size breadboard

PRODUCT ID: 64
This is a cute half size breadboard, good for small projects. It's 2.2" x 3.4" (5.5 cm x 8.5 cm) with a standard double-strip in the middle and two power rails on both...
$5.00
IN STOCK

Breadboarding wire bundle

PRODUCT ID: 153
75 flexible stranded core wires with stiff ends molded on in red, orange, yellow, green, blue, brown, black and white. These are a major improvement over the "box of bent...
$4.95
IN STOCK
This guide was first published on Oct 17, 2018. It was last updated on Nov 17, 2018. This page (Overview) was last updated on Oct 17, 2018.