I have the following code:

#include <SoftwareSerial.h>
#include <Keyboard.h>

SoftwareSerial ttySerial(10, 11); // RX, TX
void setup()
  // Open serial communications and wait for port to open:
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Native USB only

  Serial.println("Serial Initialized");

  //Set the data rate for the SoftwareSerial port
  ttySerial.println("tty Initialized");


void loop() 
  while (ttySerial.available())

//    if (Serial.available())
//      ttySerial.write(Serial.read());

my problem is that ttySerial.read() is an int and I thought that the Keyboard.write method could hand integer arguments: Keyboard.write(32) should write "< space >" not "32".

Any ideas what is going on?

  • i do not see Keyboard.write(32) in your code ... what are you doing to send byte 32 to the sketch? – jsotola Mar 4 '20 at 2:46
  • @jsotola thats because I am writing byte 32 to the RX Pin using SoftwareSerial. The ttySerial.read() is where I recover that and want it to be written using Keyboard.write. Simply put ttySerial.read() == byte 32 (but can also take on the form of other bytes) – Sterling Butters Mar 4 '20 at 2:53
  • And what is the problem? Is this program misbehaving? If so, what it it doing? What behavior do you expect instead? – Edgar Bonet Mar 4 '20 at 12:47
  • 2
    you could use parseInt. or send bytes not text. what is the sender? send ' ' not "32" – Juraj Mar 4 '20 at 15:48
  • 1
    You can send arbitrary data with a JavaScript buffer. For instance, both Buffer.from([32]) and Buffer.from(' ') will give you a buffer holding a single byte with the numeric value 32. – Edgar Bonet Mar 4 '20 at 17:34

write will treat an int as a number and assume you want it converted to ascii. Try casting that to char:


The print class treats char variables as if they are already ascii codes.

  • Are you saying I should try Keyboard.print(...)? Or .write as you have? – Sterling Butters Mar 5 '20 at 2:58
  • I'm saying that either way you have to feed it a char if it is an ascii code. And yeah, I'd probably use print there. – Delta_G Mar 5 '20 at 3:12
  • Well I tried (char)... at one point but the behavior still wasn't write but I didn't do it using .print not sure if that would make the difference - I'll have to try it out next week but I'll let you know – Sterling Butters Mar 5 '20 at 3:30
  • Delta_G, read the comments please – Juraj Mar 5 '20 at 5:05

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