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I'm looking at this specification page:

http://arduino.cc/en/Main/ArduinoBoardMega2560

It says there are 54 digital input pins. How many of those can be used at the same time to measure pulse input frequency? I've seen examples of a couple pins being used at the same time, but can it handle measuring frequency on say 12 pins at the same time?

Also I am looking at this bluetooth shield:

http://redbearlab.com/bleshield/

Would there be a limit on the number of simultaneous frequency measuring pulse pins when then this is added?

Currently I use an IOIO board and can monitor 9 pulseInput pins (at least it seems like it is simultaneous, but probably not, it has a PIC24FJ256GB206 microcontroller that has 9 input capture modules when used as single precision.) It works well with my around 15-30 Hz signals updated every 250 milliseconds. I'm wanting to move it to arduino for supported connectivity to many other devices. What are the capabilities of the arduino mega?

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migrated from electronics.stackexchange.com Mar 14 at 1:21

This question came from our site for electronics and electrical engineering professionals, students, and enthusiasts.
    
What are you using to measure? –  Ignacio Vazquez-Abrams Mar 14 at 1:18
    
@IgnacioVazquez-Abrams I think I will be using the pulseIn() method. –  coconuts4eva Mar 14 at 1:21
    
This depends on how long "the same time" lasts, and what frequencies you want to measure. There is no way for the processor to do anything simultaniously, but it can check all the pins in succession relativly fast. Thats no guarentee its fast enough though. BTW, pulseIn can only measure one pin at a time. –  BrettAM Mar 14 at 3:41
    
@BrettAM Currently I use an IOIO board and can monitor 9 pulseInput() pins (at least it seems like it is simultaneous, but probably not, it has a PIC24FJ256GB206 microcontroller that has 9 input capture modules when used as single precision.) It works well with my around 15-30 Hz signals updated every 250 milliseconds. I'm wanting to move it to arduino for supported connectivity to many other devices. What are the capabilities of the arduino mega? –  coconuts4eva Mar 14 at 15:12

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