Sample Code DHT11 – dht.py #
import utime
import rp2
from rp2 import PIO, asm_pio
from machine import Pin
@asm_pio(set_init=(PIO.OUT_HIGH),autopush=True, push_thresh=8)
def DHT11_PIO():
# clock set at 500Khz Cycle is 2us
# drive output low for at least 20ms
set(y,1) # 0
pull() # 1
mov(x,osr) # 2
set(pindirs,1) # 3 set pin to output
set(pins,0) # 4 set pin low
label ('waitx')
jmp(x_dec,'waitx') # 5 decrement x reg every 32 cycles
set(pindirs,0) # 6 set pin to input
# STATE A. Wait for high at least 80us. max should be very short
set(x,31) # 7
label('loopA')
jmp(pin,'got_B') # 8
jmp(x_dec,'loopA') # 9
label('Error')
in_(y,1) # 10
jmp('Error') # 11 Infinity loop error
# STATE B. Get HIGH pulse. max should be 40us
label('got_B')
set(x,31) # 12
label('loop_B')
jmp(x_dec,'check_B') # 13
jmp('Error') # 14
label('check_B')
jmp(pin,'loop_B') # 15
# STATE C. Get LOW pulse. max should be 80us
set(x,31) # 16
label('loop_C')
jmp(pin,'got_D') # 17
jmp(x_dec,'loop_C') # 18
jmp('Error') # 19
# STATE D. Get HIGH pulse. max should be 80us
label('got_D')
set(x,31) # 20
label('loop_D')
jmp(x_dec,'check_D') # 21
jmp('Error') # 22
label('check_D')
jmp(pin,'loop_D') # 23
# STATE E. Get Low pulse delay. should be around 50us
set(x,31) # 24
label('loop_E')
jmp(pin,'got_F') # 25
jmp(x_dec,'loop_E') # 26
jmp('Error') # 27
# STATE F.
# wait 40 us
label('got_F')
nop() [20] # 28
in_(pins,1) # 29
# now wait for low pulse
set(x,31) # 30
jmp('loop_D') # 31
class DHT11:
def __init__(self,dataPin, powerPin=None,dht11=False,smID=1):
self.dataPin = dataPin
self.powerPin = powerPin
self.dht11 = dht11
self.smID = smID
self.dataPin.init(Pin.IN, Pin.PULL_UP)
if self.powerPin is not None:
self.powerPin.init(Pin.OUT)
self.powerPin.value(0)
self.sm= rp2.StateMachine(self.smID)
def read_array(self):
if self.powerPin is not None:
self.powerPin.value(1)
utime.sleep_ms(100)
#start state machine
self.sm.init(DHT11_PIO,freq=500000,
set_base=self.dataPin,
in_base=self.dataPin,
jmp_pin=self.dataPin)
if self.dht11:
self.sm.put(10000)
else:
self.sm.put(1000)
self.sm.active(1)
value = []
for i in range(5):
value.append(self.sm.get())
self.sm.active(0)
return value
def read(self):
value = self.read_array()
sumV = 0
for i in range(4):
sumV += value[i]
if (sumV & 0xff) == value[4]:
if self.dht11:
humidity=value[0] & 0x7f
temperature=value[2]
else:
humidity=((value[0]<<8) + value[1])/10.0
temperature=(((value[2] &0x7f) << 8) + value[3]) /10.0
if (value[2] & 0x80) == 0x80:
temperature = -temperature
return temperature, humidity
else:
return None, None
if __name__ == "__main__":
from machine import Pin
from DHT11 import DHT11
import utime
dht_data = Pin(15,Pin.IN,Pin.PULL_UP)
dht_sensor=DHT11(dht_data,Pin(14,Pin.OUT),dht11=False)
while True:
T,H = dht_sensor.read()
if T is None:
print(" sensor error")
else:
print("{:3.1f}'C {:3.1f}%".format(T,H))
#DHT22 not responsive if delay to short
utime.sleep_ms(1000)
Sample Code main.py #
from machine import Pin
from time import sleep
from dht import DHT11
pin = Pin(15,Pin.IN,Pin.PULL_UP)
dht11 = DHT11(pin,None,dht11=True)
while True:
sleep(1)
T,H = dht11.read()
if T is None:
print(" sensor error")
else:
print("Temperature :" + str(T) + "C "+ "Humidity:"+ str(H) +"%")
Sample Code Oled – oled_main.py #
from machine import I2C,Pin, ADC
from time import sleep
from ssd1306 import SSD1306_I2C
from dht import DHT11
i2c = I2C(0, sda = Pin(0), scl = Pin(1), freq = 400000)
oled = SSD1306_I2C(128, 64,i2c)
dht_data = Pin(15,Pin.IN,Pin.PULL_UP)
dht11 = DHT11(dht_data,None,dht11=True)
for x in range(65, 1, -1):
oled.fill(0)
oled.text("Welcome to",20,x)
oled.text("voidlooprobotech", 0, (x+12))
oled.show()
sleep(0.02)
oled.text("DHT11 with",21,28)
oled.text("Raspberry Pi", 12,42)
oled.text("PICO board", 19,56)
oled.show()
for x in range(1, 5, 1):
oled.invert(1)
sleep(.5)
oled.invert(0)
sleep(.5)
sleep(0.5)
while True:
T,H = dht11.read()
if T is None:
print(" sensor error")
else:
print("Temperature :" + str(T) + "C "+ "Humidity:"+ str(H) +"%")
oled.fill(0)
oled.text("Welcome to",20,1)
oled.text("voidlooprobotech", 0,12)
oled.text("Temperature:" + str (T) + "C",0,28)
oled.text("Humidity:" + str (H) + "%", 12,42)
oled.text("Subscribe Please", 0,56)
oled.show()
sleep(1)
Sample Code SSD1306 Oled Driver – ssd1306.py #
# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
from micropython import const
import framebuf
# 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)
# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
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)
super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
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.width > 2 * self.height 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 poweron(self):
self.write_cmd(SET_DISP | 0x01)
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)
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)
self.write_list = [b"\x40", None] # Co=0, D/C#=1
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.temp[0] = 0x80 # Co=1, D/C#=0
self.temp[1] = cmd
self.i2c.writeto(self.addr, self.temp)
def write_data(self, buf):
self.write_list[1] = buf
self.i2c.writevto(self.addr, self.write_list)
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
import time
self.res(1)
time.sleep_ms(1)
self.res(0)
time.sleep_ms(10)
self.res(1)
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(0)
self.cs(0)
self.spi.write(bytearray([cmd]))
self.cs(1)
def write_data(self, buf):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(1)
self.cs(0)
self.spi.write(buf)
self.cs(1)
