send null data

[Fred Gibson]

Hi

I am having great fun transmitting data from multiple arduino 328s.  Some of the data points are blank ie no data but the received data reads as 0.  How do I get the receiving station to record the 0 as a blank.

I send  45, 23.4,  ,  ,  5 but I receive 45  23.4  0  0  5

I copy  blocks of received data to excel for graphing so "0" are a real pain.

[Greg Fenton]

Have you considered sending a negative number for 0 such as -1?

If you are sending the individual characters rather than the value
('1' '0' rather than 10) you could always send 'B' to represent a
blank and parse for 'B' at the receiving end.

There are many options available to you if you are controlling the data sent.

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[Fred Gibson]

[Fred Gibson]

On Thursday, 13 February 2014 09:50:32 UTC, Fred Gibson wrote:

[Fred Gibson]

[Fred Gibson]

Thanks for your quick reply.  I tried sending -1 but  I received -1

I tried to change the received 0 to a " " but ran up against problems.  Having declared the individual data points as either int or Float  " " does not compute.  I do control the sent data.  The data chain consists of at present sensor readings from three sources.  If source 1 is sending then the data points from the other two sensors should be blank.  Unfortunately the blank is received as a 0 which screws up by excel graph

[Greg Fenton]

If only one data point at a time is valid then send the other two as the same value eg sensor 1: 120, sensors 2 and 3 as -1.

Add a formula in excel to only display if the value is different from the other 2 cells.

[Fred Gibson]

[Fred Gibson]

I can't get the hang of this forum system.  Hence the number of empty emails.  I can now modify the "0" cells in excel and convert them to blanks.  However if there is a method to do the same in Arduino "c++" i would be most obliged.

On Thursday, 13 February 2014 09:50:32 UTC, Fred Gibson wrote: