Posted at 2014-09-19 by @gfwilliams

Hi,

Serial.write(X) will always write 8 bits for numbers - but if you supply a string or array it'll write each element separately as 8 bits.

To do it 'nicely', I'd use Typed Arrays. The code would look a bit like:

var buffer = new ArrayBuffer(16); // 8 bytes
var i32 = new Int32Array(buffer);
var i16 = new Int16Array(buffer);
var i8 = new Int8Array(buffer);

i8[4] = 255; 
// buffer = [0,0,0,0,255,0,0,0];
i16[2] = 0x0102; 
// buffer = [0,0,0,0,2,1,0,0];
i32[1] = 0x01020304; 
// buffer = [0,0,0,0,4,3,2,1];

// Finally:
Serial1.write(buffer);

You don't have to be 'aligned' either. You can do:

var x32 = new Int32Array(buffer,2 /* 2 bytes offset*/);
x32[0] = 0x01020304; 
// buffer = [0,0,4,3,2,1,0,0];

Hope that helps!

Posted at 2014-09-20 by user48681

Thanks, I'll try it out and report :)

Posted at 2014-09-20 by user48681

One more thing,

when reading data using the .on('data', function(data) {...}), do I need to create a buffer out of the string? Is the data always string? The docs seem to say so

Posted at 2014-09-20 by user48681

I can confirm that the sending works fine and I get responses back :) Thanks again

Posted at 2014-09-20 by @gfwilliams

Great, glad it's going!

when reading data using the .on('data', function(data) {...}), do I need to create a buffer out of the string? Is the data always string? The docs seem to say so

Yes, the data is always a string. You can use it as-is using data.charCodeAt(..), but if you want to access the binary data as an array, a nice easy way is to use E.toArrayBuffer(string)