communicate with wifi module

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi, i have tried to use arduino to communicate with a wifi module,
so that i can send message from the computer to the arduino.
i connect the data out pin of the module to the Rx of the arduino,
and i use the following code to read the serial data from the wifi module:

int val;

void setup()
{
Serial.begin(115200);
}

void loop()
{
if(Serial.available()>0)
{
val = Serial.read();
Serial.print(val,HEX);

}
}

the data i suppose to read is "aa 1b 00 01 ef 77 00 00 00 00 00 00",
but what i have read in the arduino is "95 EE FD 21 44 FF FF FF FF FF".
Does anyone know why the data is converted?and how to do this conversion?

the maunal of the wifi module:
http://www.hlktech.com/main/DownLoad.asp?ProId=200912814492990&oBoardId=200741015142065

2

Looks like your module is outputting RS232. the arduino needs TTL serial. The voltages are different and there is a logic inversion. You need a converter circuit. One easy circuit is to use a MAX202 or similar.

By the way my browser (Fire Fox) can't cope with that link.

3

thanks Grumpy_Mike!!!
it works!!