NodeMCU Projects

From Network Security Wiki



Small Projects

Playing with GPIO

import machine
import time
import urandom

pin = machine.Pin(2, machine.Pin.OUT)

def toggle(p):
   p.value(not p.value())

while True:
   time.sleep_ms(urandom.getrandbits(8))
   toggle(pin)


Fading an LED

import time, math
import machine

led = machine.PWM(machine.Pin(2), freq=1000)

def pulse(l, t):
    for i in range(20):
        l.duty(int(math.sin(i / 10 * math.pi) * 500 + 500))
        time.sleep_ms(t)

while True:
    pulse(led, 20)


Control a hobby servo

  1. Hobby servo motors can be controlled using PWM.
  2. They require a frequency of 50Hz and a duty between about 40 and 115, with 77 being the center value.
  • Manual Movements
servo = machine.PWM(machine.Pin(12), freq=50)
servo.duty(40)
servo.duty(115)
servo.duty(77)
  • Random movements:
servo = machine.PWM(machine.Pin(12), freq=50)
while True:
   servo.duty(urandom.getrandbits(8))
   time.sleep(1)

One Wire DS18B20 Temp Sensor

import time
import machine
import onewire, ds18x20

# the device is on GPIO12
dat = machine.Pin(12)

# create the onewire object
ds = ds18x20.DS18X20(onewire.OneWire(dat))

# scan for devices on the bus
roms = ds.scan()
print('found devices:', roms)

# loop 10 times and print all temperatures
for i in range(10):
    print('temperatures:', end=' ')
    ds.convert_temp()
    time.sleep_ms(750)
    for rom in roms:
        print(ds.read_temp(rom), end=' ')
    print()

LM35 Temp Sensor

        This section is under construction.

DHT11 Temp Sensor

        This section is under construction.

Deep-sleep mode

  • This shut down the ESP8266 and all its peripherals & also WiFi.
  • But not including the real-time-clock, which is used to wake the chip.
  • This drastically reduces current consumption and is a good way to make devices that can run for a while on a battery.
  • You Must connect GPIO16 to the reset pin.
import machine

# configure RTC.ALARM0 to be able to wake the device
rtc = machine.RTC()
rtc.irq(trigger=rtc.ALARM0, wake=machine.DEEPSLEEP)

# check if the device woke from a deep sleep
if machine.reset_cause() == machine.DEEPSLEEP_RESET:
    print('woke from a deep sleep')

# set RTC.ALARM0 to fire after 10 seconds (waking the device)
rtc.alarm(rtc.ALARM0, 10000)

# put the device to sleep
machine.deepsleep()

Analog Temperature Meter

Requirements: 

DS18B20 Temperature sensor
Servo Motor
Micropython based NodeMCU

Wiring details: 

Servo motor = D4 => GPIO 2
DS18B20     = D7 => GPIO 13

import time
import machine
import onewire, ds18x20

# the device is on GPIO13
dat = machine.Pin(13)

# create the onewire object
ds = ds18x20.DS18X20(onewire.OneWire(dat))

# scan for devices on the bus
roms = ds.scan()
print('found devices:', roms)

# servo is connected to GPIO2
servo = machine.PWM(machine.Pin(2), freq=50)

# Function for mapping range
def translate(value, leftMin, leftMax, rightMin, rightMax):
    # Figure out how 'wide' each range is
    leftSpan = leftMax - leftMin
    rightSpan = rightMax - rightMin

    # Convert the left range into a 0-1 range (float)
    valueScaled = float(value - leftMin) / float(leftSpan)

    # Convert the 0-1 range into a value in the right range.
    return rightMin + (valueScaled * rightSpan)
 
# print all temperatures
while True:
    ds.convert_temp()
    time.sleep_ms(1000)
    for rom in roms:
        print(ds.read_temp(rom))
    temp = ds.read_temp(rom)
    srv = translate(temp, 20, 35, 115, 40)
    print(int(srv))
    if (temp>=20) & (temp<=35):
        servo.duty(int(srv))
    else:
        print("Out of Range")

NeoPixel

import machine
import neopixel
import time
import urandom

pin = machine.Pin(14, machine.Pin.OUT)     # WS2812 data pin connected to GPIO 14 or Pin D5
np = neopixel.NeoPixel(pin, 16)            #16 Pixels or LEDs in strip

def rand():
    return urandom.getrandbits(7)

def cycle():
    for i in range(16):
        np[i] = (128,0,0)
        np.write()
        time.sleep_ms(25)

    for i in range(16):
        np[i] = (0,128,0)
        np.write()
        time.sleep_ms(25)

    for i in range(16):
        np[i] = (0,0,128)
        np.write()
        time.sleep_ms(25)

def circle():
    for j in range(10):
        x,y,z = rand(),rand(),rand()
        for i in range(16):
            np[i] = (x,y,z)
            np.write()
            time.sleep_ms(25)

def circle_rainbow():
    for j in range(10):
        for i in range(16):
            np[i] = (rand(),rand(),rand())
            np.write()
            time.sleep_ms(25)

def fade():
    for i in range(0, 4 * 256, 8):
            for j in range(16):
                if (i // 256) % 2 == 0:
                    val = i & 0xff
                else:
                    val = 255 - (i & 0xff)
                np[j] = (val, 0, 0)
            np.write()

    for i in range(0, 4 * 256, 8):
            for j in range(16):
                if (i // 256) % 2 == 0:
                    val = i & 0xff
                else:
                    val = 255 - (i & 0xff)
                np[j] = (0, val, 0)
            np.write()

    for i in range(0, 4 * 256, 8):
            for j in range(16):
                if (i // 256) % 2 == 0:
                    val = i & 0xff
                else:
                    val = 255 - (i & 0xff)
                np[j] = (0, 0, val)
            np.write()

def clock():
    for k in range(10):
        for i in range(16):
            if i%2 == 0:
                np[i] = (64,0,10)
                np.write()
            else:
                np[i] = (10,64,0) 
                np.write()
        time.sleep_ms(200)

        for j in range(16):
            if j%2 == 0:
                np[j] = (10,64,0)
                np.write()
            else:
                np[j] = (64,10,0)
                np.write()
        time.sleep_ms(200)

def bounce():
    for i in range(3):
        x,y,z = rand(),rand(),rand()
        for i in range(4 * 16):
            for j in range(16):
                np[j] = (x,y,z)
            if (i // 16) % 2 == 0:
                np[i % 16] = (0, 0, 0)
            else:
                np[16 - 1 - (i % 16)] = (0, 0, 0)
            np.write()
            time.sleep_ms(60)

def off():
    for i in range(16):
        np[i] = (0,0,0)
        np.write()

cycle()
off()
time.sleep(1)

circle()
off()
time.sleep(1)

circle_rainbow()
off()
time.sleep(1)

fade()
off()
time.sleep(1)

clock()
off()
time.sleep(1)

bounce()
off()

Morse Code

import machine
import sys
import time

CODE = {'A': '.-',     'B': '-...',   'C': '-.-.', 
        'D': '-..',    'E': '.',      'F': '..-.',
        'G': '--.',    'H': '....',   'I': '..',
        'J': '.---',   'K': '-.-',    'L': '.-..',
        'M': '--',     'N': '-.',     'O': '---',
        'P': '.--.',   'Q': '--.-',   'R': '.-.',
     	'S': '...',    'T': '-',      'U': '..-',
        'V': '...-',   'W': '.--',    'X': '-..-',
        'Y': '-.--',   'Z': '--..',   ' ': ' ',
        
        '0': '-----',  '1': '.----',  '2': '..---',
        '3': '...--',  '4': '....-',  '5': '.....',
        '6': '-....',  '7': '--...',  '8': '---..',
        '9': '----.' 
        }

pin = machine.Pin(14, machine.Pin.OUT)        # Laser Module connected to GPIO 14 or Pin D5
pin.off()
a = 300

def morse(x):
    c = []
    for i in x:
        c.append(CODE[i.upper()])
        c.append(" ")

    for i in range(len(c)):
        for j in c[i]:
            if j == ".":
                pin.on()
                print("DOT")
                time.sleep_ms(a)
                pin.off()
                time.sleep_ms(a*2)
            elif j == "-":
                pin.on()
                print("DASH")
                time.sleep_ms(a*3)
                pin.off()
                time.sleep_ms(a*2)
            elif j == " ":
                pin.off()
                print(" ")
                time.sleep_ms(a*4)
            else:
                print("ERROR")
    pin.off()
    print("END")

morse("amandeep")

I2C LCD

https://forum.micropython.org/viewtopic.php?f=16&t=2858 https://forum.micropython.org/viewtopic.php?f=16&t=2858&start=30

https://github.com/dhylands/python_lcd/tree/master/lcd esp8266_i2c_lcd.py lcd_api.py 

D1 SCL ------------ SCL
D2 SDA ------------ SDA
GND --------------- GND
5V ---------------- VCC


There are two versions of this device - the difference is the controller IC. If you have the PCF8574T. the default I2C bus address is 0x27. If you have the PCF8574AT the default I2C bus address is 0x3F. An i2c.scan() should reveal which address to use

lcd=I2cLcd(i2c, 0x27, 2, 16) lcd=I2cLcd(i2c, 39, 2, 16) 

>>> from machine import I2C
>>> i2c = I2C(scl=Pin(5), sda=Pin(4), freq=400000)
>>> print(i2c.scan())

>>> print(i2c.scan())
[63]
>>> lcd=I2cLcd(i2c, 63, 2, 16)



References





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