Eliminating letters from a character array of ascii letters,

Projects Programming
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I have a PC sending my Arduino two sets of characters through a USB to Serial cable. Each set is made up of two initial letters followed by three numerals. I have succeeded in using the atoi function to extract the numerals for conversion into two integer values, but the program appears to be running through the read routine four times, I believe that it is reading the letters and numerals separately. Attached is a rough first attempt at the program. I am not sure but I think that I need to parse out the letters out in order to get just two reads to produce the two integer values themselves. These are azmuth and elevation data sets, each is preceded by an az or an el. I just need the angle data after those letters. My solution was to simply toggle the write to the two servos which will receive this data through the Arduino Servo library. Any suggestions or comments would be appreciated.

toggle_servo_assignment_version_of_Working_Drinking_straw_point.ino (1.52 KB)

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Post code inline can't read from my phone...

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C has a few canned functions...
isalpha(). isdigit() and isalnum() - all of which you could use - either as the characters are arriving, or you could strip them out of your received buffer.

Or much the same way, you could ignore characters < 0 or > 9. if you only want digits. .