#include <TM1637.h>
#include "TM1637Display.h"
#include <Arduino.h>
#include <DHT.h>

int CLK = 2;
int DIO = 3;
#define DHTPIN 5     // Digital pin connected to the DHT sensor
// Feather HUZZAH ESP8266 note: use pins 3, 4, 5, 12, 13 or 14 --
// Pin 15 can work but DHT must be disconnected during program upload.

// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   

DHT dht(DHTPIN, DHTTYPE);


TM1637Display display(CLK, DIO);

void setup() {
          display.setBrightness(0x0f);
  
}

void loop() {
          display.showNumberDec(-999); 
}


tm1637-example.ino

diagram.json

# Wokwi Library List
# See https://docs.wokwi.com/guides/libraries

Grove 4-Digit Display
DHT sensor library

libraries.txt


//  Author: avishorp@gmail.com
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

extern "C" {
  #include <stdlib.h>
  #include <string.h>
  #include <inttypes.h>
}

#include "TM1637Display.h"
#include <Arduino.h>

#define TM1637_I2C_COMM1    0x40
#define TM1637_I2C_COMM2    0xC0
#define TM1637_I2C_COMM3    0x80

//
//      A
//     ---
//  F |   | B
//     -G-
//  E |   | C
//     ---
//      D
const uint8_t digitToSegment[] = {
 // XGFEDCBA
  0b00111111,    // 0
  0b00000110,    // 1
  0b01011011,    // 2
  0b01001111,    // 3
  0b01100110,    // 4
  0b01101101,    // 5
  0b01111101,    // 6
  0b00000111,    // 7
  0b01111111,    // 8
  0b01101111,    // 9
  0b01110111,    // A
  0b01111100,    // b
  0b00111001,    // C
  0b01011110,    // d
  0b01111001,    // E
  0b01110001     // F
  };

static const uint8_t minusSegments = 0b01000000;

TM1637Display::TM1637Display(uint8_t pinClk, uint8_t pinDIO, unsigned int bitDelay)
{
	// Copy the pin numbers
	m_pinClk = pinClk;
	m_pinDIO = pinDIO;
	m_bitDelay = bitDelay;

	// Set the pin direction and default value.
	// Both pins are set as inputs, allowing the pull-up resistors to pull them up
    pinMode(m_pinClk, INPUT);
    pinMode(m_pinDIO,INPUT);
	digitalWrite(m_pinClk, LOW);
	digitalWrite(m_pinDIO, LOW);
}

void TM1637Display::setBrightness(uint8_t brightness, bool on)
{
	m_brightness = (brightness & 0x7) | (on? 0x08 : 0x00);
}

void TM1637Display::setSegments(const uint8_t segments[], uint8_t length, uint8_t pos)
{
    // Write COMM1
	start();
	writeByte(TM1637_I2C_COMM1);
	stop();

	// Write COMM2 + first digit address
	start();
	writeByte(TM1637_I2C_COMM2 + (pos & 0x03));

	// Write the data bytes
	for (uint8_t k=0; k < length; k++)
	  writeByte(segments[k]);

	stop();

	// Write COMM3 + brightness
	start();
	writeByte(TM1637_I2C_COMM3 + (m_brightness & 0x0f));
	stop();
}

void TM1637Display::clear()
{
    uint8_t data[] = { 0, 0, 0, 0 };
	setSegments(data);
}

void TM1637Display::showNumberDec(int num, bool leading_zero, uint8_t length, uint8_t pos)
{
  showNumberDecEx(num, 0, leading_zero, length, pos);
}

void TM1637Display::showNumberDecEx(int num, uint8_t dots, bool leading_zero,
                                    uint8_t length, uint8_t pos)
{
  showNumberBaseEx(num < 0? -10 : 10, num < 0? -num : num, dots, leading_zero, length, pos);
}

void TM1637Display::showNumberHexEx(uint16_t num, uint8_t dots, bool leading_zero,
                                    uint8_t length, uint8_t pos)
{
  showNumberBaseEx(16, num, dots, leading_zero, length, pos);
}

void TM1637Display::showNumberBaseEx(int8_t base, uint16_t num, uint8_t dots, bool leading_zero,
                                    uint8_t length, uint8_t pos)
{
    bool negative = false;
	if (base < 0) {
	    base = -base;
		negative = true;
	}


    uint8_t digits[4];

	if (num == 0 && !leading_zero) {
		// Singular case - take care separately
		for(uint8_t i = 0; i < (length-1); i++)
			digits[i] = 0;
		digits[length-1] = encodeDigit(0);
	}
	else {
		//uint8_t i = length-1;
		//if (negative) {
		//	// Negative number, show the minus sign
		//    digits[i] = minusSegments;
		//	i--;
		//}
		
		for(int i = length-1; i >= 0; --i)
		{
		    uint8_t digit = num % base;
			
			if (digit == 0 && num == 0 && leading_zero == false)
			    // Leading zero is blank
				digits[i] = 0;
			else
			    digits[i] = encodeDigit(digit);
				
			if (digit == 0 && num == 0 && negative) {
			    digits[i] = minusSegments;
				negative = false;
			}

			num /= base;
		}
    }
	
	if(dots != 0)
	{
		showDots(dots, digits);
	}
    
    setSegments(digits, length, pos);
}

void TM1637Display::bitDelay()
{
	delayMicroseconds(m_bitDelay);
}

void TM1637Display::start()
{
  pinMode(m_pinDIO, OUTPUT);
  bitDelay();
}

void TM1637Display::stop()
{
	pinMode(m_pinDIO, OUTPUT);
	bitDelay();
	pinMode(m_pinClk, INPUT);
	bitDelay();
	pinMode(m_pinDIO, INPUT);
	bitDelay();
}

bool TM1637Display::writeByte(uint8_t b)
{
  uint8_t data = b;

  // 8 Data Bits
  for(uint8_t i = 0; i < 8; i++) {
    // CLK low
    pinMode(m_pinClk, OUTPUT);
    bitDelay();

	// Set data bit
    if (data & 0x01)
      pinMode(m_pinDIO, INPUT);
    else
      pinMode(m_pinDIO, OUTPUT);

    bitDelay();

	// CLK high
    pinMode(m_pinClk, INPUT);
    bitDelay();
    data = data >> 1;
  }

  // Wait for acknowledge
  // CLK to zero
  pinMode(m_pinClk, OUTPUT);
  pinMode(m_pinDIO, INPUT);
  bitDelay();

  // CLK to high
  pinMode(m_pinClk, INPUT);
  bitDelay();
  uint8_t ack = digitalRead(m_pinDIO);
  if (ack == 0)
    pinMode(m_pinDIO, OUTPUT);


  bitDelay();
  pinMode(m_pinClk, OUTPUT);
  bitDelay();

  return ack;
}

void TM1637Display::showDots(uint8_t dots, uint8_t* digits)
{
    for(int i = 0; i < 4; ++i)
    {
        digits[i] |= (dots & 0x80);
        dots <<= 1;
    }
}

uint8_t TM1637Display::encodeDigit(uint8_t digit)
{
	return digitToSegment[digit & 0x0f];
}

TM1637Display.cpp

//  Author: avishorp@gmail.com
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

#ifndef __TM1637DISPLAY__
#define __TM1637DISPLAY__

#include <inttypes.h>

#define SEG_A   0b00000001
#define SEG_B   0b00000010
#define SEG_C   0b00000100
#define SEG_D   0b00001000
#define SEG_E   0b00010000
#define SEG_F   0b00100000
#define SEG_G   0b01000000
#define SEG_DP  0b10000000

#define DEFAULT_BIT_DELAY  100

class TM1637Display {

public:
  //! Initialize a TM1637Display object, setting the clock and
  //! data pins.
  //!
  //! @param pinClk - The number of the digital pin connected to the clock pin of the module
  //! @param pinDIO - The number of the digital pin connected to the DIO pin of the module
  //! @param bitDelay - The delay, in microseconds, between bit transition on the serial
  //!                   bus connected to the display
  TM1637Display(uint8_t pinClk, uint8_t pinDIO, unsigned int bitDelay = DEFAULT_BIT_DELAY);

  //! Sets the brightness of the display.
  //!
  //! The setting takes effect when a command is given to change the data being
  //! displayed.
  //!
  //! @param brightness A number from 0 (lowes brightness) to 7 (highest brightness)
  //! @param on Turn display on or off
  void setBrightness(uint8_t brightness, bool on = true);

  //! Display arbitrary data on the module
  //!
  //! This function receives raw segment values as input and displays them. The segment data
  //! is given as a byte array, each byte corresponding to a single digit. Within each byte,
  //! bit 0 is segment A, bit 1 is segment B etc.
  //! The function may either set the entire display or any desirable part on its own. The first
  //! digit is given by the @ref pos argument with 0 being the leftmost digit. The @ref length
  //! argument is the number of digits to be set. Other digits are not affected.
  //!
  //! @param segments An array of size @ref length containing the raw segment values
  //! @param length The number of digits to be modified
  //! @param pos The position from which to start the modification (0 - leftmost, 3 - rightmost)
  void setSegments(const uint8_t segments[], uint8_t length = 4, uint8_t pos = 0);

  //! Clear the display
  void clear();

  //! Display a decimal number
  //!
  //! Display the given argument as a decimal number.
  //!
  //! @param num The number to be shown
  //! @param leading_zero When true, leading zeros are displayed. Otherwise unnecessary digits are
  //!        blank. NOTE: leading zero is not supported with negative numbers.
  //! @param length The number of digits to set. The user must ensure that the number to be shown
  //!        fits to the number of digits requested (for example, if two digits are to be displayed,
  //!        the number must be between 0 to 99)
  //! @param pos The position of the most significant digit (0 - leftmost, 3 - rightmost)
  void showNumberDec(int num, bool leading_zero = false, uint8_t length = 4, uint8_t pos = 0);

  //! Display a decimal number, with dot control
  //!
  //! Display the given argument as a decimal number. The dots between the digits (or colon)
  //! can be individually controlled.
  //!
  //! @param num The number to be shown
  //! @param dots Dot/Colon enable. The argument is a bitmask, with each bit corresponding to a dot
  //!        between the digits (or colon mark, as implemented by each module). i.e.
  //!        For displays with dots between each digit:
  //!        * 0.000 (0b10000000)
  //!        * 00.00 (0b01000000)
  //!        * 000.0 (0b00100000)
  //!        * 0.0.0.0 (0b11100000)
  //!        For displays with just a colon:
  //!        * 00:00 (0b01000000)
  //!        For displays with dots and colons colon:
  //!        * 0.0:0.0 (0b11100000)
  //! @param leading_zero When true, leading zeros are displayed. Otherwise unnecessary digits are
  //!        blank. NOTE: leading zero is not supported with negative numbers.
  //! @param length The number of digits to set. The user must ensure that the number to be shown
  //!        fits to the number of digits requested (for example, if two digits are to be displayed,
  //!        the number must be between 0 to 99)
  //! @param pos The position of the most significant digit (0 - leftmost, 3 - rightmost)
  void showNumberDecEx(int num, uint8_t dots = 0, bool leading_zero = false, uint8_t length = 4, uint8_t pos = 0);

  //! Display a hexadecimal number, with dot control
  //!
  //! Display the given argument as a hexadecimal number. The dots between the digits (or colon)
  //! can be individually controlled.
  //!
  //! @param num The number to be shown
  //! @param dots Dot/Colon enable. The argument is a bitmask, with each bit corresponding to a dot
  //!        between the digits (or colon mark, as implemented by each module). i.e.
  //!        For displays with dots between each digit:
  //!        * 0.000 (0b10000000)
  //!        * 00.00 (0b01000000)
  //!        * 000.0 (0b00100000)
  //!        * 0.0.0.0 (0b11100000)
  //!        For displays with just a colon:
  //!        * 00:00 (0b01000000)
  //!        For displays with dots and colons colon:
  //!        * 0.0:0.0 (0b11100000)
  //! @param leading_zero When true, leading zeros are displayed. Otherwise unnecessary digits are
  //!        blank
  //! @param length The number of digits to set. The user must ensure that the number to be shown
  //!        fits to the number of digits requested (for example, if two digits are to be displayed,
  //!        the number must be between 0 to 99)
  //! @param pos The position of the most significant digit (0 - leftmost, 3 - rightmost)
  void showNumberHexEx(uint16_t num, uint8_t dots = 0, bool leading_zero = false, uint8_t length = 4, uint8_t pos = 0);

  //! Translate a single digit into 7 segment code
  //!
  //! The method accepts a number between 0 - 15 and converts it to the
  //! code required to display the number on a 7 segment display.
  //! Numbers between 10-15 are converted to hexadecimal digits (A-F)
  //!
  //! @param digit A number between 0 to 15
  //! @return A code representing the 7 segment image of the digit (LSB - segment A;
  //!         bit 6 - segment G; bit 7 - always zero)
  static uint8_t encodeDigit(uint8_t digit);

protected:
   void bitDelay();

   void start();

   void stop();

   bool writeByte(uint8_t b);

   void showDots(uint8_t dots, uint8_t* digits);
   
   void showNumberBaseEx(int8_t base, uint16_t num, uint8_t dots = 0, bool leading_zero = false, uint8_t length = 4, uint8_t pos = 0);


private:
	uint8_t m_pinClk;
	uint8_t m_pinDIO;
	uint8_t m_brightness;
	unsigned int m_bitDelay;
};

#endif // __TM1637DISPLAY__