Od razu polecam świetny poradnik ACROBOTIC

Programowanie z Arduino IDE
Do managera Arduino IDE => Preferences wpisać należy ten link:
http://arduino.esp8266.com/stable/package_esp8266com_index.json
Następnie w Tools/Board/Boards Manager odszukać board esp8266 by ESP8266 Community I zainstalować:
Z listy Boards wybieramy LOLIN(WEMOS) D1 R2 & mini:

Budowa płytki
https://wiki.wemos.cc/_media/products:d1:mini_new_v2_2_0.pdf

from
https://klovimg.com/image/HvMti
Pin | Function | ESP-8266 Pin |
TX | TXD | TXD |
RX | RXD | RXD |
A0 | Analog input, max 3.3V input | A0 |
D0 | IO | GPIO16 |
D1 | IO, SCL | GPIO5 |
D2 | IO, SDA | GPIO4 |
D3 | IO, 10k Pull-up | GPIO0 |
D4 | IO, 10k Pull-up, BUILTIN_LED | GPIO2 |
D5 | IO, SCK | GPIO14 |
D6 | IO, MISO | GPIO12 |
D7 | IO, MOSI | GPIO13 |
D8 | IO, 10k Pull-down, SS | GPIO15 |
G | Ground | GND |
5V | 5V | – |
3V3 | 3.3V | 3.3V |
RST | Reset | RST |
All of the IO pins have interrupt/pwm/I2C/one-wire support except D0.
All of the IO pins run at 3.3V.
#define PIN_WIRE_SDA (4)
#define PIN_WIRE_SCL (5)
static const uint8_t SDA = PIN_WIRE_SDA;
static const uint8_t SCL = PIN_WIRE_SCL;
#define LED_BUILTIN 2
static const uint8_t D0 = 16;
static const uint8_t D1 = 5;
static const uint8_t D2 = 4;
static const uint8_t D3 = 0;
static const uint8_t D4 = 2;
static const uint8_t D5 = 14;
static const uint8_t D6 = 12;
static const uint8_t D7 = 13;
static const uint8_t D8 = 15;
static const uint8_t RX = 3;
static const uint8_t TX = 1;
SCHEMAT D1 mini
LINKI:
- Using ESP8266 GPIO0/GPIO2/GPIO15 pins
- wiki.wemos.cc/tutorials:get_started:get_started_in_arduino
- uczymy.edu.pl wemos-d1-mini-esp8266-troche-inaczej
- www.wemos.cc
- New Wemos D1 Mini Shields: ESP-12S and ESP8285
- Ciekawy wątek z forum na temat zasilania ESP8266 D1 Mini
- Hack WeMos D1 mini into SeeedStudio Wio Link
- http://100-x-arduino.blogspot.com/2016/07/esp-na-powaznie-cz-3.html