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[on:]

Hi,

I want to wirelessly transfer a larger amount of data (camera picture from a Hacrocam) from my arduino mega to my PC (processing). I use XRF modules (XBee like UART <-> RF devices). There are some transmission errors and the XRFs don't offer any retransmit mechanisms. So I need to implement them myself.

I wonder if someone implemented something like this before and could share its experience and/or code.
I found this link: http://hacromatic.com/blog/2012/08/make-your-serial-protocol-robust-with-8-bit-crc-codes/ which might be a good start.

Thanks
Robert

[Reply #1 on:]

This might not what you are looking for (break a butterfly on a wheel) but when i hear

retransmit mechanisms

I almost directly think about a nice TCP Protocol (had to Programm some Server an Client Applications  , only not for Arduino). I know in the Arduino Wi-Fi Shield they use TCP. le Link to the Library:
https://github.com/arduino/wifishield/tree/master/libraries/WiFi/utility
socket, server_drv and spi_drv could be of interest for you to implement TCP. In the parent folders you should find examples on how to send and receive data using TCP. I think you would almost only have to change the spi_drv funktions to insteed talk to your XRF modul.

[Reply #2 on:]

Thanks a lot. But I think a full TCP protocoll might indeed be overdone. :-)