LUA and ESP-8266 - What a wonderful world !

Guess what, I bumped onto a blogpost discussing a cheap Wifi-module for Arduino. A sub 5USD module with an embedded ARM processor on board. Unbeatable price and feature set !

After doing some research, I bought the ESP-12 module on Aliexpress :

It's a stamp-sized module, with a serial port and a bunch of GPIO's :

I connected my USB-Serial convertor (I have a CH340G with selectable 3.3/5V) and after figuring out the correct pinout , I flashed the LUA-firmware on it.

ESP8266	CH340G-SerialUSB
VCC	VCC
GND	GND
RX	TX
TX	RX

Holding GPIO15 = LOW, and CH_PD = HIGH activates the module.
Communication is possible @9600,8,N,1 in this mode.
Holding GPIO0 = LOW, brings the module in bootstrap mode and download of a new firmware is possible.

I chose to upload a new firmware :  nodemcu-firmware using the esp8266flasher.exe software.

From then on, you can talk to the module using the Serial.line and setup the module by either executing commands or by writing the lua.init file. I used a textfile with commands, allowing easy push to the ESP-module.

When reusing existing code, it is important to check the GPIO-mapping. In my case the LUA-Gpio's map as follows to the Hardware pins :

This means that IO (7) is actually using hw-pin GPIO13 !

Once the Module has been connected to the Wifi-AP, everything is straightforward.

Sending a command :
<< http://192.168.2.108/gpio7=0 >> will clear  GPIO13 on the board !
<< http://192.168.2.108/gpio7=1 >> will set  GPIO13 on the board !

Imagine what you could do !