Raspberry pi will not send serial data to an arduino using either minicom or python -

i trying raspberry pi communicate arduino using tx/rx pins. have arduino programmed send ascii code letter received.

code:

byte number = 0;  void setup() {   serial.begin(9600); }  void loop() {   if (serial.available())     {     number = serial.read();     serial.print("character recieved: ");     serial.println(number, dec);   } } 

but when open minicom , type it, nothing happens. if open arduino's serial monitor , send character minicom displays "character recieved: " , characters ascii code. tried creating python program using py serial,

code:

import serial ser = serial.serial('/dev/ttyama0', 9600, timeout=1) ser.open()  ser.write("testing") try:         while 1:                 response = ser.readline()                 print response except keyboardinterrupt:         ser.close() 

but nothing displayed. have looked on internet, have found no solution. please help, in advance.

you need read on difference between arduino , rasppi 'serial' pins - in short, voltage levels quite different , require conversion cable between 2 of them adjust these levels.