GSM noticeboard using 8x8 MAX7219 display

Projects General Guidance
1

Hi guys,

I am currently working on a project that uses a SIM900 shield, arduino and a cascaded 8x8 matrix (currently 32x8). The plan is once I send an SMS to the shield, that will send the data to the serial output connected up to the arduino and then this will be displayed on the matrix.

My question is once the SMS has been received and placed into an array, is it possible to obtain the decimal value for each character according to the ASCII table as I need that to be able to choose the correct binary sequence for representing characters on the display later on from another array.

So if the message "Hi" is stored in the array, the decimal value is 72 which will be used to look into the array and read the pattern of bytes as shown below.

B10001000, //H
B10001000,
B10001000,
B11111000,
B10001000,
B10001000,
B10001000,

2

Characters are stored by their ascii value so you already have what you need.

char msg[] = "Hello";
for( int i = 0; i < length(msg); ++i ) {
  int val = msg[i];
  Serial.print( val );
}
3

Thanks for your help I wondered if i could do that, but thought it was too simple :slight_smile: