[OpenTRV-dev] Experiment with RockBLOCK

Jonathan Smith jonsmith at mail.com
Tue Aug 4 07:47:34 BST 2015

Hi All,

Damon asked me to forward this on to the group.  If anyone wants a copy of
the python script let me know.

Hi Damon,

Unfortunately the bits I ordered to make the rockblock work with the
Arduino didn't arrive before we left for our road trip.  However I managed
to throw a raspberry pi, a few wires, an old bluetooth gps receiver and a
usb battery pack into my bag in the hope that I would be able to get
something working on our way.

The raspberry pi uses 3.3v on the logic lines, so was safe to connect up to
the rockblock.  I managed to get something working whilst we were in
Galicia.  I had the pi and the rockblock on the rear parcel shelf and so it
would get a good view of the sky.  Unfortunately the pi didn't always
switch on, something to do with the UPS shield I have attached to the pi I
think.  The UPS shield was useful as it had a couple of LEDs and buttons I
could use via i2c.


I would much rather have used the Arduino to keep it simple but since the
parts didn't arrive in time at least this solution meant I got some use out
of the rockblock.

I used the pyRockBLOCK library to communicate with it:


I also went round a few locations in London yesterday evening to see how
the rockblock performs without such a good view of the sky.  As expected
the results were a bit hit and miss, but generally after a few attempts it
was possible to get a successful transmission, even with a limited view of
the sky or under the cover of trees.  It even managed, on one occasion, to
transmit from within the train carriage - I found this hard to believe and
there is a small chance it could have performed the transmit of the stale
location after I got off the train - but looking at where it transmitted I
don't think the train would have got to my home station before the default
timeout which seemed to be a couple of minutes.

I've put the results on my website for you with a couple of photos of the
places in London that I tried the transmissions from.


Unfortunately I cannot see a record of the transmissions made yesterday on
the core7 web page, and the results didn't get published to my website, so
I manually collated the results from the logs on the client side.  The
client reported a successful transmission and returned a seq number.  The
trial must have run out earlier than expected.

I've attached the python script I hacked up in a hurry!

Anyway, hope this helps.  It's interesting to see the GPS locations vs the
Iridium determined location, I've plotted these on a google map.

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