Its going to be pretty difficult to get a 38,400 baud “take photo” command out 
to six cameras at once when you get a signal from your accelerometer.  Without 
some real-time patches, Linux may have a response latency of 100 msec for a 
user-space program and with them 50 usec for an interrupt-driven kernel-mode 
driver. (That you get to write!)  I think you could do it by using one of the 
PRUs to bitbang that command to six different GPIOs at the same time.  Then the 
PRU would have to bitbang the six Rx GPIOs (since BBB doesn’t have enough 
UARTs) to capture the images.  Or maybe each camera will store its image until 
you send it a “download” command?  Then you could use three GPIO outputs to 
control an 8-way MUX chip, so you could receive the images one at a time from 
each camera using one of the UARTs.

You could also try using a little bit of programmable logic (like a CPLD) so 
you could use some GPIO pins to select the camera destination for one UART’s 
output.  Then you could select the destination as “all cameras” when you send 
the “take photo” command, and each individual camera when you send a “download” 
command.

From: [email protected] 
Sent: Thursday, February 27, 2014 5:52 PM
To: [email protected] 
Subject: [beagleboard] Using multiple TTL serial cameras with beagle bone. 
PLEASE help arduino sucks.

Hi all,

I am working on my graduation project and need advice on using the beagle bone. 
I want to control up to 6 of these cameras: 
https://www.adafruit.com/products/397   to take a picture at the same time when 
my accelerometer detects free fall. I have been using the arduino UNO and have 
been able to take 2 pictures at the same time when free fall is detected, but 
now when i connect another camera the arduino can't handle it. Could this be 
done with the beagle bone? Is there a way to transfer my arduino code to beagle 
bone, it will be great since it has taken me a long time. Please help, i will 
greatly appreciate it. 
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