Driving PolargraphSD wirelessly

I’m finally on top of assembly so can pause for breath.  Thank you to the folks who are still waiting, your machines will be coming to you in the next week or two (at the most).

I wanted to let people know that there’s a couple of neat features in the Polarshield, the first of which is an XBee-shaped socket that can take a wireless transceiver.

It’s as easy as that.  There’s a weak line in the case that can be cut away if you wanted to do this.  This is a great way of simplifying installation of a polargraph machine in a particular space.  I used a wireless connection just like this in the Spectrum Arts machine so that I could do the machine setup / calibration manually and do any little pen tests I wanted to make sure ink was flowing, then draw from SD.  There I used XBees, here I’m using XRF modules (and a Bee Adapter for the PC end).

One foible I came across with my XRFs (maybe I was being dumb) is that I couldn’t get my PC to talk to the PC-side XRF any faster than 9600 baud.  Which is unfortunate because the default rate that the polargraph controller speaks at is 57600 baud, so I added a property to the controller that changes that rate.  If you need to use it, you’ll have to edit the properties file – there isn’t a visible control for it in the application itself.

But once that’s done, it just works as a serial cable replacement: Great!  It doesn’t work for reprogramming the arduino firmware yet – I tried to get that working but never did, so you still need to use a USB cable for that.

A wireless module is not supplied as part of any kit – I decided these are still too expensive, and a little too far outside my expertise to start troubleshooting, but the socket is there for those who would like it.

6 thoughts on “Driving PolargraphSD wirelessly

  1. Sandy,

    Sweet! I received my PolargraphSD yesterday, and gearing up to print, saw this post. Ultimately, I would like to print wirelessly but have never used an Xbee.
    What do I need?
    * One or two XBees?
    * One or two XRFs?
    * Or a combination of XBee(s) and XRF(s)?



    • Glad it arrived safely!

      Right, you need a pair of modules, xbee or xrf (or there’s a load of different kinds of wireless modules with this footprint). They are basically serial cable replacements. The thing on the right-hand side in the pic is a bee adapter – this is what the PC plugs into with it’s USB cable. It’s a xbee socket with an FTDI chip onboard to allow a USB connection.

      The modules are normally programmed individually to talk to each other using a proprietary bit of software beforehand. This sets the speed that they communicate with whatever they are plugged into. For Polargraph it shoud be 57600 baud.

      I did get a bluetooth module that has the ‘bee footprint, but never had much success in getting it working.

      Good luck!

  2. Pulled the trigger! Ordered two XRFs, a breakout board, and the XRF USB dongle!

    Will report back once I get them…



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