ESP-12E: ESP8266 Serial Port WIFI Wireless Transceiver Module for Arduino

The low power consumption is the real selling point here — my project runs for days on a small battery without draining it. It pairs with the Arduino in about a minute, and the price for this level of UART-WiFi functionality is hard to beat.

I was worried about pairing it with my Arduino, but the UART connection was straightforward and it connected to my wifi on the first try. The module’s size is tiny yet sturdy, and the low power consumption means I don’t have to babysit the battery. Solid little board for the price.

The low power draw is what sold me—my battery-powered sensor rig runs for days now without swapping cells. Paired it with an Arduino in about twenty minutes and the UART link held steady through a full afternoon of data logging. For the price, this thing punches way above its weight.