Multiple TTL serial cameras with the arduino UNO

Hello everyone !

I am trying to get 4 of these cameras to work at the same time and then store the images into the SD card for a school project :

http://www.adafruit.com/products/397

I am able to get one to work perfectly but i have no clue on how to get more than 1 to work. I found this video, which shows 2 working but no step by step description:

http://garygfletcher.wordpress.com/2012 ... omment-118

I am trying to get in contact with the guy but nothing so far. This is his brief description: "A lot of people seem to have struggled to implement reading multiple serial cameras on Arduino due to the hardware limitations, this is a software solution that uses a pointer to the connection and a listen command to iterate through each cameras “motion detected” state. It seems to work vey well."

Does anyone know how to do this? Please let me know, i will GREATLY appreciate your help.

I don't know where comment 118 is. This is a pretty simple camera. Adafruit has sample code. You just learn the software serial listen(). Because only one software serial port can be listening, you need to switch which one is listening. I've tried this camera on uno but software serial produces too many bad images, 5-15% images are bad, not acceptable for me, so I moved on to hardware serial on mega. I ended up using 2 cameras. Just create 2 software serial ports, and two cameras. Before switching camera, make that corresponding software serial port listen first.

http://arduino.cc/en/Reference/SoftwareSerialListen

I am able to get one to work perfectly but i have no clue on how to get more than 1 to work. I found this video, which shows 2 working but no step by step description:

Below is the video. You Probably could do somewhat the same thing electrically by putting a small signal diode in the tx line from the cam tx to the arduino rx. Connect the diode band side to the cam tx. Note that with the cams operating independently in the motion detect mode they could have interference with each other if they transmit at the same time.

http://www.youtube.com/watch?v=18eEeoFpsE8

Link to the video:

http://garygfletcher.wordpress.com/2012/10/18/multiple-serial-cameras-running-on-arduino/comment-page-1/#comment-118

"A lot of people seem to have struggled to implement reading multiple serial cameras on Arduino due to the hardware limitations, this is a software solution that uses a pointer to the connection and a listen command to iterate through each cameras “motion detected” state. It seems to work vey well."

The below discussion might be of interest.

http://forum.arduino.cc/index.php?topic=214335.0