Setting up a two-way radio link between 2 Raspberry Pis


#1

I’d like to use the Cisco Slice of Radio boards to link two Raspberry Pis. In particular, I wish to use one Pi as a ‘master’, running a control programme, and the other as a ‘slave’, carrying out the received instructions and reporting back for further instructions (preferably, all coded in Python).
Is this easily feasible?
Reason for asking: The two Pis are to be used in a marine environment (remote from land-based internet) and separated by distances where a cable connection would be difficult and inhibiting.


#2

Definitely possible but you’d need to write some software to achieve it. :-)

There is some more information about getting two Slice of Radios talking to each other here (specifically step 3): http://openmicros.org/index.php/articles/94-ciseco-product-documentation/raspberry-pi/282-b023-slice-of-radio

Sounds like an interesting project, let us know how you get on!


#3

That’s encouraging: thank you.
But I could use a little more advice:

  1. If I were to connect my Pis via an ethernet cable, I’d exploit the socket module to get them to behave (almost) like a single ‘SuperPi’. How would I achieve a similar level of integration using a wireless connection via their serial ports? (Which, incidentally, might get a bit crowded as I’m also hanging a GPS, a motor controller and a couple of accelerometers on the same ports - or the I2C.) It’s not clear to me from the suggested reading how I’d handle such problems.
  2. Which of your wireless products would you recommend? The Ciseco ‘Slice of Radio’ was the first to appeal to me but I note that you can also supply XRF, ERF, URF & ARF boards and an SRF stick. Wireless range shouldn’t be a problem (30-40 ft. max.) but radio noise might be (large marine diesel engine, brushed motors and lots of shipboard electronics, including 5 watt VHF transceiver).
    I’d appreciate your guidance before final commitment.
    Many thanks,
    docjim

#4

Just a possible suggestion. Have a look at “eRA Connect2 Pi”. The guys at lprs.co.uk are very knowledgeable and helpful. I have been using lprs for many years (with a similar product). Paul


#5

Have you considered using Wifi? Configure one Pi with Wifi dongle as an access point, connect the other Pi to it. That way you would

  • get a faster connection
  • be able to use standard TCP/IP protocols without any special drivers
  • leave your GPIO free for whatever you need to connect.

Radio interference still sounds like it would be an issue, possibly even more of a problem than with the “Slice of Radio” you mention.