Use CircuitPython 7.0.0-alpha.4 or newer for the code in this guide!
Are you new to using CircuitPython? No worries, there is a full getting started guide here.
Adafruit suggests using the Mu editor to edit your code and have an interactive REPL in CircuitPython. You can learn about Mu and installation in this tutorial.
Download the Project Bundle
Your project will use a specific set of CircuitPython libraries and the code.py file. In order to get the libraries you need, click on the Download Project Bundle link below, and uncompress the .zip file.
Drag the contents of the uncompressed bundle directory onto your board's CIRCUITPY drive, replacing any existing files or directories with the same names, and adding any new ones that are necessary.
# SPDX-FileCopyrightText: 2021 Jeff Epler for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import board
import displayio
import i2cdisplaybus
import keypad
import adafruit_displayio_sh1107
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS
from adafruit_display_text import label
from adafruit_bitmap_font import bitmap_font
try:
import usb_hid
except ImportError:
usb_hid = None
K_SQ = "√"
K_CL = "<clear>"
K_FN = "<fn>"
K_PA = "<paste>"
KEYMAP0 = [
K_CL, K_FN, '%', '/',
'7', '8', '9', '*',
'4', '5', '6', '-',
'1', '2', '3', '+',
'0', '.', K_SQ, '='
]
KEYMAP1 = [
K_CL, None, '', '',
'', '', '', '',
'', '', '', '',
'', '', '', '',
'', '', '', K_PA,
]
keymaps = {
0: KEYMAP0,
1: KEYMAP1,
}
# pylint: disable=redefined-outer-name
def lookup(layer, key_number):
while layer >= 0:
key = keymaps[layer][key_number]
if key is not None:
return key
layer -= 1
return None
displayio.release_displays()
# oled_reset = board.D9
# Use for I2C
i2c = board.I2C() # uses board.SCL and board.SDA
# i2c = board.STEMMA_I2C() # For using the built-in STEMMA QT connector on a microcontroller
display_bus = i2cdisplaybus.I2CDisplayBus(i2c, device_address=0x3C)
# SH1107 is vertically oriented 64x128
WIDTH = 128
HEIGHT = 64
display = adafruit_displayio_sh1107.SH1107(display_bus, width=WIDTH, height=HEIGHT, rotation=180)
display.auto_refresh = False
font = bitmap_font.load_font("/digit-16px.pcf")
text_area = label.Label(font, text=" ", line_spacing=0.95)
text_area.y = 8
display.root_group = text_area
N = float
unary = {
K_SQ: lambda a: a**.5,
}
binary = {
'+': (lambda a, b: a+b, lambda a, b: a * (1+b/100)),
'-': (lambda a, b: a-b, lambda a, b: a * (1-b/100)),
'*': (lambda a, b: a*b, lambda a, b: a * (b/100)),
'/': (lambda a, b: a/b, lambda a, b: a / (b/100)),
}
class Calculator:
def __init__(self):
self._number1 = N("0")
self._number2 = None
self.trail = ["Ready."]
self.entry = ""
self.op = None
self.keyboard = None
self.keyboard_layout = None
def paste(self, text):
if self.keyboard is None:
if usb_hid:
self.keyboard = Keyboard(usb_hid.devices)
self.keyboard_layout = KeyboardLayoutUS(self.keyboard)
else:
return
if self.keyboard_layout is None:
self.add_trail("No USB")
else:
text = str(text)
self.keyboard_layout.write(text)
self.add_trail(f"Pasted {text}")
def add_trail(self, msg):
self.trail = self.trail[-3:] + [str(msg).upper()]
@property
def number1(self):
return self._number1
@number1.setter
def number1(self, number):
self._number1 = number
self.add_trail(number)
@property
def number2(self):
if self.entry == "":
if self._number2 is not None:
return self._number2
return None
return N(self.entry)
@number2.setter
def number2(self, number):
self._number2 = number
self.entry = ''
def clear(self):
self.number1 = N("0")
def clear_entry(self):
self.number2 = None
def key_pressed(self, k): # pylint: disable=too-many-branches
if k == K_CL:
if self.entry:
self.entry = self.entry[:-1]
elif self.op:
print("clear op")
self.op = None
elif self.number2 is None:
self.clear()
else:
print("clear entry - op = ", self.op)
self.clear_entry()
if len(k) == 1 and k in "0123456789":
self.entry = self.entry + k
if k == "." and not "." in self.entry:
if self.entry == "":
self.entry = "0"
self.entry = self.entry + k
if k == K_PA:
if self.number2 is not None:
self.paste(self.number2)
else:
self.paste(self.number1)
if k == "=":
self.do_binary_op(0)
if k == "%":
self.do_binary_op(1)
op = unary.get(k)
if op:
self.do_unary_op(op)
if k in binary:
if self.number2 is not None:
if self.op:
self.do_binary_op(0)
else:
self.number1 = self.number2
self.clear_entry()
self.op = k
def do_unary_op(self, op):
if self.number2 is not None:
self.number2 = op(self.number2)
else:
self.number1 = op(self.number1)
def do_binary_op(self, i):
if self.op and self.number2 is not None:
op = binary[self.op][i]
self.op = None
self.number1 = op(self.number1, self.number2)
self.clear_entry()
def show(self):
rows = [""] * 4
trail = self.trail
if len(trail) > 0:
rows[2] = trail[-1]
if len(trail) > 1:
rows[1] = trail[-2]
if len(trail) > 2:
rows[0] = trail[-3]
entry_or_number = self.entry or self.number2
cursor = ' :' if (self.number2 is None or self.entry != "") else ""
op = self.op or ''
op = 'd' if op == '/' else op
rows[-1] = f"{op}{entry_or_number or ''}{cursor}"
for r in rows:
print(r)
text_area.text = "\n".join(rows)
km=keypad.KeyMatrix(
row_pins=(board.A2, board.A1, board.A3, board.A0, board.D0),
column_pins=(board.D25, board.D11, board.D12, board.D24))
calculator=Calculator()
calculator.show()
layer = 0
while True:
ev = km.events.get()
if ev:
key = lookup(layer, ev.key_number)
if ev.pressed:
if key == K_FN:
layer = 1
try:
calculator.key_pressed(key)
except Exception as e: # pylint: disable=broad-except
calculator.add_trail(e)
calculator.show()
elif ev.released:
if key == K_FN:
layer = 0
else:
display.refresh()
Adapting to other Adafruit Feather boards
The code can be adapted to most Adafruit Feather boards that support CircuitPython, but the Feather RP2040 board names some pins differently than most boards, so you'll need to make modifications. Find the portion of the code that creates the KeyMatrix and change D24/D25 to A4/A5 for most other Feathers:
km=keypad.KeyMatrix(
row_pins=(board.A2, board.A1, board.A3, board.A0, board.D0),
column_pins=(board.A5, board.D11, board.D12, board.A4))
Page last edited January 22, 2025
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