Consider the humble calculator. Now just an app that you always have with you on your telephone, an electronic calculator used to be a technological marvel.

In this project, you'll build your own calculator with an Adafruit Feather RP2040, 128x64 OLED display, and 20 keys. Optional 3D printed parts like an enclosure and even the keycaps themselves make for a sharp presentation. Make it your own by customizing the code, or use the hardware for your own MacroPad-inspired project.

Custom Printed Circuit Board

This project needs a custom PCB. You can pick up the KiCad (design) files or the Gerber (production) files below and upload them to the PCB house of your choice, or you can use this link to order them from OSH Park. You are free to modify the design files and use them in your own designs. (In copyright terms, the design files are licensed as CC0)

OSH Park's standard turnaround is 9 to 12 days from order to shipment, so plan accordingly.

The board files were designed in KiCad, open source software that is free to download & use.

Required Parts

Along with the custom PCB, you'll need basic tools, soldering supplies, and the Adafruit parts listed below.

Angle shot of Feather RP2040 prototype
A new chip means a new Feather, and the Raspberry Pi RP2040 is no exception. When we saw this chip we thought "this chip is going to be awesome when we give it the Feather...
$11.95
In Stock
Video of a Adafruit FeatherWing OLED - 128x64 OLED Add-on For Feather - STEMMA QT / Qwiic connected to a temp and humidity sensor. Display reads "Adafruit" and various Temp and Humidity measures.
A Feather board without ambition is a Feather board without FeatherWings! This is the FeatherWing 128x64 OLED: it adds a gorgeous 128x64 monochrome OLED plus 3...
$14.95
In Stock
White Nylon Screw and Stand-off Set with M2.5 Threads, kit box
Totaling 420 pieces, this White Nylon M2.5 Screw Set is a must-have smörgåsbord for your workstation. You'll have more than enough...
$14.95
In Stock
Angled shot of a pink/purple woven USB cable plugged into a laptop port and a small dev board.
This cable is not only super-fashionable, with a woven pink and purple Blinka-like pattern, it's also made for USB C for our modernized breakout boards, Feathers and more. 
$3.95
In Stock
Angled shot of a Header Kit for Feather - 12-pin and 16-pin Female Header Set.
These two Female Headers alone are, well, lonely. But pair them with any of our 
Out of Stock
Angled shot of a Stacking Headers for Feather - 12-pin and 16-pin female headers.
These two Female Stacking Headers alone are, well, lonely. But pair them with any of our Feather boards and...
$1.25
In Stock
10 pack 1N4148 Signal Diode
You have some electrons over here, and you want them over there but you don't want the electrons from over there to be able to come over here? That's what a diode is for, these...
$1.50
In Stock
Pick up 2 ten-packs of diodes, you need one for each key!
Angled shot of ten red Kailh key switches.
For crafting your very own custom keyboard, these Kailh Red Linear mechanical key switches are deeee-luxe! With smooth actuation and Cherry MX compatibility,...
$6.95
In Stock
Angled shot of ten white plastic keycaps.
Get ready to customize your keeb with a 10 pack of two-part plastic keycaps for your next mechanical keyboard or 
$4.95
In Stock
Pack of 4 Little Rubber Bumper Feet
Keep your electronics from going barefoot, give them little rubber feet! These small sticky bumpers are our favorite accessory for any electronic kit or device. They are sticky, but...
$0.95
In Stock

Optional parts

1 x Tapered Heat-Set Inserts for Plastic
Brass, M2.5 x 0.45 mm Thread Size, 3.4 mm Installed Length (Pack of 100)

This guide was first published on Jul 13, 2021. It was last updated on 2021-07-13 16:06:28 -0400.

This page (Overview) was last updated on May 13, 2022.

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