from hcsr04 import HCSR04
from machine import Pin,I2C
import ssd1306
 
i2c = I2C(scl=Pin(22), sda=Pin(21), freq=100000)      
lcd=ssd1306.SSD1306_I2C(128,64,i2c) 
 
sensor = HCSR04(trigger_pin=12, echo_pin=13,echo_timeout_us=1000000)
 
try:
  while True:
    distance = sensor.distance_cm()
    print("Distance value in cm:", distance)
    lcd.fill(0)
    lcd.text("Distance value:",14,20) 
    lcd.text(str(distance),30,40)
    lcd.show()
except KeyboardInterrupt:
       pass    

main.py

diagram.json

# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
from micropython import const
import time
import framebuf
import sys
 
currentBoard=""
if(sys.platform=="esp8266"):
  currentBoard="esp8266"
elif(sys.platform=="esp32"):
  currentBoard="esp32"
elif(sys.platform=="pyboard"):
  currentBoard="pyboard"
  import pyb
# register definitions
SET_CONTRAST        = const(0x81)
SET_ENTIRE_ON       = const(0xa4)
SET_NORM_INV        = const(0xa6)
SET_DISP            = const(0xae)
SET_MEM_ADDR        = const(0x20)
SET_COL_ADDR        = const(0x21)
SET_PAGE_ADDR       = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP       = const(0xa0)
SET_MUX_RATIO       = const(0xa8)
SET_COM_OUT_DIR     = const(0xc0)
SET_DISP_OFFSET     = const(0xd3)
SET_COM_PIN_CFG     = const(0xda)
SET_DISP_CLK_DIV    = const(0xd5)
SET_PRECHARGE       = const(0xd9)
SET_VCOM_DESEL      = const(0xdb)
SET_CHARGE_PUMP     = const(0x8d)
class SSD1306:
  def __init__(self, width, height, external_vcc):
    self.width = width
    self.height = height
    self.external_vcc = external_vcc
    self.pages = self.height // 8
    self.buffer = bytearray(self.pages * self.width)
    self.framebuf = framebuf.FrameBuffer(self.buffer, self.width, self.height, framebuf.MVLSB)
    self.poweron()
    self.init_display()
  def init_display(self):
    for cmd in (
      SET_DISP | 0x00, # off
      # address setting
      SET_MEM_ADDR, 0x00, # horizontal
      # resolution and layout
      SET_DISP_START_LINE | 0x00,
      SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
      SET_MUX_RATIO, self.height - 1,
      SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
      SET_DISP_OFFSET, 0x00,
      SET_COM_PIN_CFG, 0x02 if self.height == 32 else 0x12,
      # timing and driving scheme
      SET_DISP_CLK_DIV, 0x80,
      SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1,
      SET_VCOM_DESEL, 0x30, # 0.83*Vcc
      # display
      SET_CONTRAST, 0xff, # maximum
      SET_ENTIRE_ON, # output follows RAM contents
      SET_NORM_INV, # not inverted
      # charge pump
      SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14,
      SET_DISP | 0x01): # on
      self.write_cmd(cmd)
    self.fill(0)
    self.show()
  def poweroff(self):
    self.write_cmd(SET_DISP | 0x00)
  def contrast(self, contrast):
    self.write_cmd(SET_CONTRAST)
    self.write_cmd(contrast)
  def invert(self, invert):
    self.write_cmd(SET_NORM_INV | (invert & 1))
  def show(self):
    x0 = 0
    x1 = self.width - 1
    if self.width == 64:
      # displays with width of 64 pixels are shifted by 32
      x0 += 32
      x1 += 32
    self.write_cmd(SET_COL_ADDR)
    self.write_cmd(x0)
    self.write_cmd(x1)
    self.write_cmd(SET_PAGE_ADDR)
    self.write_cmd(0)
    self.write_cmd(self.pages - 1)
    self.write_data(self.buffer)
  def fill(self, col):
    self.framebuf.fill(col)
  def pixel(self, x, y, col):
    self.framebuf.pixel(x, y, col)
  def scroll(self, dx, dy):
    self.framebuf.scroll(dx, dy)
  def text(self, string, x, y, col=1):
    self.framebuf.text(string, x, y, col)
  def hline(self, x, y, w, col):
    self.framebuf.hline(x, y, w, col)
  def vline(self, x, y, h, col):
    self.framebuf.vline(x, y, h, col)
  def line(self, x1, y1, x2, y2, col):
    self.framebuf.line(x1, y1, x2, y2, col)
  def rect(self, x, y, w, h, col):
    self.framebuf.rect(x, y, w, h, col)
  def fill_rect(self, x, y, w, h, col):
    self.framebuf.fill_rect(x, y, w, h, col)
  def blit(self, fbuf, x, y):
    self.framebuf.blit(fbuf, x, y)
 
class SSD1306_I2C(SSD1306):
  def __init__(self, width, height, i2c, addr=0x3c, external_vcc=False):
    self.i2c = i2c
    self.addr = addr
    self.temp = bytearray(2)
    super().__init__(width, height, external_vcc)
  def write_cmd(self, cmd):
    self.temp[0] = 0x80 # Co=1, D/C#=0
    self.temp[1] = cmd
    #IF SYS  :
    global currentBoard
    if currentBoard=="esp8266" or currentBoard=="esp32":
      self.i2c.writeto(self.addr, self.temp)
    elif currentBoard=="pyboard":
      self.i2c.send(self.temp,self.addr)
    #ELSE:
          
  def write_data(self, buf):
    self.temp[0] = self.addr << 1
    self.temp[1] = 0x40 # Co=0, D/C#=1
    global currentBoard
    if currentBoard=="esp8266" or currentBoard=="esp32":
      self.i2c.start()
      self.i2c.write(self.temp)
      self.i2c.write(buf)
      self.i2c.stop()
    elif currentBoard=="pyboard":
      #self.i2c.send(self.temp,self.addr)
      #self.i2c.send(buf,self.addr)
      self.i2c.mem_write(buf,self.addr,0x40)
  def poweron(self):
    pass
 
class SSD1306_SPI(SSD1306):
  def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
    self.rate = 10 * 1024 * 1024
    dc.init(dc.OUT, value=0)
    res.init(res.OUT, value=0)
    cs.init(cs.OUT, value=1)
    self.spi = spi
    self.dc = dc
    self.res = res
    self.cs = cs
    super().__init__(width, height, external_vcc)
  def write_cmd(self, cmd):
    global currentBoard
    if currentBoard=="esp8266" or currentBoard=="esp32":
      self.spi.init(baudrate=self.rate, polarity=0, phase=0)
    elif currentBoard=="pyboard":
      self.spi.init(mode = pyb.SPI.MASTER,baudrate=self.rate, polarity=0, phase=0)
    self.cs.high()
    self.dc.low()
    self.cs.low()
    global currentBoard
    if currentBoard=="esp8266" or currentBoard=="esp32":
      self.spi.write(bytearray([cmd]))
    elif currentBoard=="pyboard":
      self.spi.send(bytearray([cmd]))
    self.cs.high()
  def write_data(self, buf):
    global currentBoard
    if currentBoard=="esp8266" or currentBoard=="esp32":
      self.spi.init(baudrate=self.rate, polarity=0, phase=0)
    elif currentBoard=="pyboard":
      self.spi.init(mode = pyb.SPI.MASTER,baudrate=self.rate, polarity=0, phase=0)
    self.cs.high()
    self.dc.high()
    self.cs.low()
    global currentBoard
    if currentBoard=="esp8266" or currentBoard=="esp32":
      self.spi.write(buf)
    elif currentBoard=="pyboard":
      self.spi.send(buf)
    self.cs.high()
  def poweron(self):
    self.res.high()
    time.sleep_ms(1)
    self.res.low()
    time.sleep_ms(10)
    self.res.high()

ssd1306.py

import machine, time
from machine import Pin
 
class HCSR04:
    """
    Driver to use the untrasonic sensor HC-SR04.
    The sensor range is between 2cm and 4m.
    The timeouts received listening to echo pin are converted to OSError('Out of range')
    """
    # echo_timeout_us is based in chip range limit (400cm)
    def __init__(self, trigger_pin, echo_pin, echo_timeout_us=500*2*30):
        """
        trigger_pin: Output pin to send pulses
        echo_pin: Readonly pin to measure the distance. The pin should be protected with 1k resistor
        echo_timeout_us: Timeout in microseconds to listen to echo pin. 
        By default is based in sensor limit range (4m)
        """
        self.echo_timeout_us = echo_timeout_us
        # Init trigger pin (out)
        self.trigger = Pin(trigger_pin, mode=Pin.OUT, pull=None)
        self.trigger.value(0)
 
        # Init echo pin (in)
        self.echo = Pin(echo_pin, mode=Pin.IN, pull=None)
 
    def _send_pulse_and_wait(self):
        """
        Send the pulse to trigger and listen on echo pin.
        We use the method `machine.time_pulse_us()` to get the microseconds until the echo is received.
        """
        self.trigger.value(0) # Stabilize the sensor
        time.sleep_us(5)
        self.trigger.value(1)
        # Send a 10us pulse.
        time.sleep_us(10)
        self.trigger.value(0)
        try:
            pulse_time = machine.time_pulse_us(self.echo, 1, self.echo_timeout_us)
            return pulse_time
        except OSError as ex:
            if ex.args[0] == 110: # 110 = ETIMEDOUT
                raise OSError('Out of range')
            raise ex
 
    def distance_mm(self):
        """
        Get the distance in milimeters without floating point operations.
        """
        pulse_time = self._send_pulse_and_wait()
 
        # To calculate the distance we get the pulse_time and divide it by 2 
        # (the pulse walk the distance twice) and by 29.1 becasue
        # the sound speed on air (343.2 m/s), that It's equivalent to
        # 0.34320 mm/us that is 1mm each 2.91us
        # pulse_time // 2 // 2.91 -> pulse_time // 5.82 -> pulse_time * 100 // 582 
        mm = pulse_time * 100 // 582
        return mm
 
    def distance_cm(self):
        """
        Get the distance in centimeters with floating point operations.
        It returns a float
        """
        pulse_time = self._send_pulse_and_wait()
 
        # To calculate the distance we get the pulse_time and divide it by 2 
        # (the pulse walk the distance twice) and by 29.1 becasue
        # the sound speed on air (343.2 m/s), that It's equivalent to
        # 0.034320 cm/us that is 1cm each 29.1us
        cms = (pulse_time / 2) / 29.1
        return cms