TM1637 + OSL40391

Raspberry Pi Python 3 TM1637 + OSL40391 Extension

A Python 3 port from MicroPython library for the quad 7-segment LED display modules based on the TM1637 LED driver, implemented on Raspberry Pi. This fork includes an extension for OptoSupply's OSL40391 4x7 Segment Display.

For example, the OptoSupply - 4 Digit Display

Examples

Basic usage

import tm1637
# tm = tm1637.TM1637(clk=5, dio=4)
tm = tm1637.TM1637_OSL40391(clk=24, dio=23)

# all LEDS on "88:88"
tm.write([127, 255, 127, 127])

# all LEDS off
tm.write([0, 0, 0, 0])

# show "0123"
tm.write([63, 6, 91, 79])

# show "COOL"
tm.write([0b00111001, 0b00111111, 0b00111111, 0b00111000])

# show "HELP"
tm.show('help')

# display "dEAd", "bEEF"
tm.hex(0xdead)
tm.hex(0xbeef)

# show "12:59"
tm.numbers(12, 59)

# show "-123"
tm.number(-123)

# show temperature '24.5*C'
tm.temperature(24.5)

# show percentage '56.7%'
tm.percent(56.7)

For more detailed examples, see tm1637_test.py

Seven Segment Font

They are called 7-segment displays as there are 7 LEDs for each digit (segment). One byte (7 lower bits) for each segment. The 8th bit (MSB) is for the colon and only on the 2nd segment.

      A
     ---
  F |   | B   *
     -G-      H (on 2nd segment)
  E |   | C   *
     ---
      D

  HGFEDCBA
0b01101101 = 0x6D = 109 = show "5"

Display	Bin	Hex	Dec
0	0b00111111	0x3F	63
1	0b00000110	0x06	6
2	0b01011011	0x5B	91
3	0b01001111	0x4F	79
4	0b01100110	0x66	102
5	0b01101101	0x6D	109
6	0b01111101	0x7D	125
7	0b00000111	0x07	7
8	0b01111111	0x7F	127
9	0b01101111	0x6F	111
A	0b01110111	0x77	119
b	0b01111100	0x7C	124
C	0b00111001	0x39	57
d	0b01011110	0x5E	94
E	0b01111001	0x79	121
F	0b01110001	0x71	113
G	0b00111101	0x3D	61
H	0b01110110	0x76	118
I	0b00000110	0x06	6
J	0b00011110	0x1E	30
K	0b01110110	0x76	118
L	0b00111000	0x38	56
M	0b01010101	0x55	85
n	0b01010100	0x54	84
O	0b00111111	0x3F	63
P	0b01110011	0x73	115
q	0b01100111	0x67	103
r	0b01010000	0x50	80
S	0b01101101	0x6D	109
t	0b01111000	0x78	120
U	0b00111110	0x3E	62
v	0b00011100	0x1C	28
W	0b00101010	0x2A	42
X	0b01110110	0x76	118
y	0b01101110	0x6E	110
Z	0b01011011	0x5B	91
blank	0b00000000	0x00	0
-	0b01000000	0x40	64
*	0b01100011	0x63	99

Methods

Get or set brightness.

brightness(val=None)

Write one or more segments at a given offset.

write(segments, pos=0)

Convert a single hex digit (0x00-0x0f) to a segment.

encode_digit(digit)

Convert a string to a list of segments.

encode_string(string, colon=False, deg=False)

Convert a single character to a segment.

encode_char(char)

Display a number in hexadecimal format 0000 through FFFF.

hex(val)

Display a number -999 through 9999, right aligned.

number(num, colon=True, deg=False)

Display 2 independent numbers on either side of the (optional) colon, with leading zeros.

numbers(num1, num2, colon=True, deg=False)

Display a temperature -9.9 through 99.9 followed by degrees C.

temperature(num)

Display a percentage 0 through 100 followed by a mimic '%'.

percent(num)

Show a string on the display. Shorthand for write(encode_string()). Limited to first 4 characters.

show(string, colon=False, deg=False)

Display a string on the display, scrolling from the right to left, speed adjustable. String starts off-screen and scrolls until off-screen at 4 FPS by default. If preset is set 0, the string starts on-screen from the left side.

scroll(string, delay=250, preset=4)

Scan a pressed key. This method returns a pressed key code, if pressed, otherwise, returns 0.

scan_key()

Parts

• OptoSupply 4 Digit Display $2 USD x 1
• HiLetgo I2C Logic Level Converter $0.75 USD x 1
• Blue LED x 1
• Akizuki BME280 Module $10 USD x 1
• Push Switch x 1
• R 10kOhm x 2
• C 100pF x 2
• C 0.1uF x 1

Connections

Raspberry Pi	4 Digit Display
GPIO24	CLK
GPIO23	DIO
5V (or 3V3)	VCC
GND	GND
:	:
:	:

See docs/clock-schematic.png for more details.

Links

• TM1637 datasheet
• Nokia 5110 version
• BBC micro:bit version

License

Licensed under the MIT License.