In the past I have built some little things using an Arduino. It is a very nice platform for controlling and measuring things in the real world. Thera are many different Arduino Board for almost every use case and you can get hundreds of shields. They are widely available for just very little money.
But there was one thing, which was missing. There was no affordable way to connect an Arduino to a wireless Network. The modules which were available did cost a lot more than the Arduino (for instance the CC3000 based modules).
It was cheaper to buy a little WIFI router and install OpenWrt on that device. One example is the TP-LINK TL-WR710N. But it had also some disadvantages. You have to maintain a complete Linux on that device and for the communication with the Arduino you had either have to use a USB serial adapter or you had to solder on the router board. The whole thing was also very bulky. For something like transmitting the values of a temperature sensor it is overkill.
Recently that changed with the availability of the ESP8266 chip. It is a very cheap 32 bit SOC with some very handy features like:
- WIFI @ 2.4 GHz, supports WPA / WPA2 security mode
- TCP / IP protocol stack
- 10 bit precision ADC
- 12 GPIO’s which can be used for PWM, I2C, SPI, UART
- Standby power consumption is less than 1.0mW
The ESP8266 operates at 1.7V – 3.6V. 5V will destroy it !! 3.3V is the best choice because other components like sensors work at 3.3V as well.
The maximum power consumption when transmitting data is 215mA. Make sure, that your power supply can deliver that.
bykting 