The team in 2016 outside Loch Insh – minus Arthur who flew back for his graduation!
We managed to update the processors so we have more RAM/Flash while keeping the same sensors deployed in 2015. Sebastian’s solar powered lithium battery packs were installed in many nodes too!
The team have been very busy making new PCBs for the final deployment in two weeks! The MS2 boards were even helped along by ECS’s new pick-and-place machine – but incredibly the Munjtac processor boards were all hand-built!
in 2016 we are testing small solar panels to charge the batteries until the snow covers them. I have just sealed them using a silicone rubber:
they also get a good MIL-spec-connector and new cable.
Our “muntjac” processor/radio board is now being tested on the original ms1 interface board. It uses a CC2538 and CC1200 as its radio and has flash storage for readings. Here you can see it sitting on top of the board – which is possible as it has the same connections as the z1.
our muntjac processor board on our ms1 board
The Muntjac is very much a shortcut for us to use an ARM core – we don’t actually use the 2.4GHz radio for example.
Router2 – which links our network over the mountains to the peat research zone had fallen over in high winds. Olivia and Emma successfully repaired it on a cold day in November:
Emma Bryder – PhD student in Dundee – helping to fix router2.
Winter was setting in and soon travel up to the sites will be very difficult. A replacement box/node/battery linked up the peat zone into the network once this was installed. Data which had been stored on peat nodes started to flow back to the server every hour (as expected) via four network hops!
In September Arthur and Kirk went to reprogram the nodes with bug fixes.
Arthur reprogramming a peat node. Not the best weather that day!
We had reduced the RAM usage of the code and removed some bugs. It also allowed us to recover readings from “lost” nodes and recharge the batteries.
Once again we had the use of the conservation buggy – to carry equipment up and down. The luggage section is useful for this activity!
This sensor node links our radio network up into the peat study area
In order to cover the study area over the ridge – we placed this sensor node in a strategic place so it passes traffic across. By this time the packets have come 3km up to the mountain then 1km across to this node – then another 600m down to the peat area.
All this with 868MHz radios running IPv6 (6LowPAN) and CoAP to gather the data!
Arthur – our superb intern team member this summer has worked very hard to get the CoAP layer working for the system and has now seen it in action on the mountain.
In 2014 we implemented an HTTP/web interface to the sensor nodes to test how much easier they would be to manage. This was successful but the large number of packets exchanged made it slow (not surprising).
In 2015 we are testing CoAP instead – as it is essentially a compressed binary form of HTTP – and only uses UDP packets – so there are far fewer radio exchanges. Initial tests in the lab with our CC1120 868MHz driver show it is very efficient – and we are now porting large parts of our code to use it. We will still be using Protocol Buffers – as they are also small binary compressed objects for data – so we should have the best of both worlds!
What this shows is a “ping” from a computer in Southampton going all the way to Glen feshie (last part via satellite link), through our “border router”, across to a node via the low power radio. It took around a second for the reply to get back to Southampton. (The IPv6 addresses have been blurred to prevent attacks).
For techies: the interval is set to 10s to prevent overloading the low power network and the packet size is set to 25 so it is small (6LowPAN prefers small packets)
view from the estate in mid April 2015 showing the low level of snow left