A hello world (blinking LED) for Micropython on the Wemos D1 Mini (ESP8266)

mp_wemos_blink.py

# See https://obviate.io/?p=8022 for more details
import time
from machine import Pin

led = Pin(2, Pin.OUT)

while True:
	if led.value():
		led.off()
	else:
		led.on()
	time.sleep_ms(250)

Why pin is 2 ? On C++ is D4

Correct, one in the same. In micropython its based on the GPIO number, rather than A/D labels, very confusing, I know. Look at https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/ who's got a good list of the different pinout's.

On my WeMos NodeMCU ESP8266 led pin is inverted. Use machine.Signal for this case https://github.com/micropython/micropython/blob/master/examples/hwapi/hwconfig_esp8266_esp12.py#L5.

from machine import Pin
from machine import ADC
from time import sleep_ms

x = ADC(Pin(2, Pin.IN))
y = ADC(Pin(5, Pin.IN))
x.atten(ADC.ATTN_11DB)
y.atten(ADC.ATTN_11DB)

while True:
    x_val = x.read()
    y_val = y.read()
    print('Current position:{},{}'.format(x_val,y_val))
    sleep_ms(300)

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
TypeError: can't convert Pin to int

what is the issue here ?