[fprint] Detect finger in sensor

[Timo Teras]

On Sun, 09 Dec 2012 11:16:35 -0600 "Ing. Alfredo Alarcon"
<frekoalarcon at gmail.com> wrote:

> Hi tank you for your answer, my application use a BeagleBone, 16x2
> LCD character and a 4x4 Keypad, must wait a finger in sensor to do de 
> identification, the fingerprint are in a MySQL database in the 
> BeagleBone, in a PC with Ubuntu and the SDK from Digital Persona to 
> kernel 2.6, do a simple call to identifcation function in a loop,
> this function wait 100 milliseconds and exit the function with a time
> out error and continue the program, but in the BeagleBone ARM i use
> the libfprint to build it in kernel 3.2, but the function identify
> stop the flow of the program, and the LCD and the keypad are not
> accessible until a finger is in the sensor, is there any way to stop
> the identify function??

I use the asynchronous API (which is not too well documented), but
works perfectly. The functions like fp_async_identify_*. You can start
the identification, and stop it when ever you want. You'll need
probably some additional glue code to integrate with the main loop -
but it's the API that works out the best for me.

- Timo