Arduino KeyPad Library

Projects Programming
1

Hi,

I am currently trying to use my arduino mega to read out input from an electronic dartboard.

i already identified how the matrix of the dartboard is built and connected everything to my arduino mega.

(It's a 4x20 matrix
with the 4 rows being single, double, triple and bullseye
and the 20 columns are the numbers from 1 to 20)

Now to my actual question, i wanted to (mis)use this library to get the data and it seemed to work fine at first, until i realized that the last 4 columns didnt give a response.
I tried using diffrent pins but it was always the last 4 i defined using the example from the library.

So after that i looked into the Code of the Library itself and found this line:

#define MAPSIZE 10		// MAPSIZE is the number of rows (times 16 columns)

and this line:

	uint bitMap[MAPSIZE];	// 10 row x 16 column array of bits. Except Due which has 32 columns.

in both cases in the comment it states something about 16 columns (which i guess is somehow defined as the max )
i couldnt find where this 16 comes from and how i can work around that.

so if anybody with a little more C knowledge than myself can help me out by finding where this 16 comes from and how i can increase that to 20, i would be very grateful!

Cheers

2

i couldnt find where this 16 comes from and how i can work around that.

How many bytes in an int? How many bits in a byte? The comment provided a HUGE clue.

You can not change the number of bits in a byte, or the number of bytes in an int.

You might be able to change the type of the array to long, and have more bits.

3

Thank you so much!

For some reason i was under the impression an int had 4 bytes which is not correct as i now know, but even if i knew, i wouldn't have made that connection.

Turning the uint array into a ulong aray did the trick and everything works fine now !

THX!

4

but even if i knew, i wouldn't have made that connection.

That's why the hint about the Due, which DOES have 32 bit int's was so important.

Turning the uint array into a ulong aray did the trick and everything works fine now !

Great.