Wifi and internet access using the Wemos d1 mini (esp8266). I recommend the LOLIN Wemos d1 Mini. These parts can all be purchased on Aliexpress at usually very low cost including shipping.

The project can also be used for analog to digital conversion, pwm on leds, i2c sensors as standalone projects.

An onboard power supply means a 6 - 30V DC external power supply can be attached for standalone projects.

I use this board for remote weather station projects via the Blynk app on cell phones.

Board makes prototyping projects really quick and easy and without the errors and damage that can occur with jumper wires.

CAUTION: The Wemos d1 Mini i/o pins work on 3.3V. Do not connect 5v to any of the i/o pins as damage will occur.

Some temperature sensors may not work reliably with 3.3v. Additional photo shows a temperature sensor plugged into the underside of the board. Reason for this is to remove temperature heating effects from the other board components. The board will accept several temperature sensors, for instance, GY21, AHT10, BME280. Example code is available on the relevant Arduino libraries.

The pcb board is marked with the i/o description. Also the gnd and voltage pins.

To make this project requires some soldering skill. The pcb is lead free.