Thursday, August 28, 2014

Koruza open-source gigabit free space optical wireless

I have previously mentioned the great work that Musti and the guys in Slovenia have been doing on open-source free-space optical links.

Basically they use a gigabit fibre transceiver aimed through a lens in a 3D-printed enclosure to beam data over a distance of up to 100m:

They are now looking to test their design with a number of test stations around the world.

We would love to install one at Arkaroola in the outback, and see just how far we can make it work in the clean dry air there.

Our good friends at NLnet Foundation have offered to sponsor the hardware for a node if we can get 10 organisations to sign up to the Open Innovation Network (the OIN) with the reference set to "NLNET/KORUZA".

The Open Innovation Network is a great idea, basically being a defensive patent pool to protection open-source projects.  The really nice thing is that you don't need any patents to join.  We signed the Serval Project up a while back (we are licensee #808).  They have some big names, like IBM and Google as members and licensees.

So take a look, and think about signing up your project if you would like to help us get a  chance to test one of these:

Next to one of these*:

* Yellow Footed Rock Wallabies only after 5pm.

Monday, August 25, 2014

Arkaroola Long-shot Wi-Fi for National Science Week

Last week was National Science Week, which had my family and I heading up to Hawker Area School and Leigh Creek Area School and Marree Aboriginal School for sessions with students, before heading up to Arkaroola to attempt to install a wireless link between the village and homestead, with the goal of later extending it to the research facility in the old shearing shed.  

The school visits were designed to give students from areas that are fairly disadvantaged some taste of science week. It was great to see a number of the students engage well, including one budding inventor from Leigh Creek. 

I have some pictures from the schools, which I need to clear with the schools before posting them. But here is the rest of the week in pictures.

To depart Tuesday morning, I needed to bring some of the equipment home from work on Monday ready to pack.  My trusty cargo bike came in handy again:

Then it was driving north on the highway, staying at Hawker and Leigh Creek for the school visits before leaving the bitumen at Copley to head over to Arkaroola.  Fortunately the roads were all open and in quite good condition:

We arrived at Arkaroola about 5:30pm after dodging lots of Yellow Footed Rock Wallabies.  It was great to see so many of them, as they were very endangered in the past, but with a lot of conservation support have made a great bounce back.

Here is the Arkaroola Village, as viewed from up by the newer observatory:

It was great to be travelling as a family, and our kids had a pretty good time, even if Caleb didn't always want to be photographed.

 There is always a lot to see if you take the time to look around at Arkaroola, although a phone camera is not the best way to capture it.  As a result the following shot is a bit of a where's-Wally to find the parrot in the shot.

After the pre-breakfast walk it was time for the first of our hands-on sessions as we set about trying to install the communications link.

It was great to have a group of seven people for most of the morning as we tried climbing a few possible locations to mount the dishes, talking about the technology and various other things along the way.  Here is one of the older in our group as we picked our way down from the summit above the old observatory trying (in vain) to see the homestead vantage point.  I did have a shot with the whole group, but it seems to have been lost.

 Here is the "Telstra pit" on the top of the vantage point behind the homestead that we were trying to see from by the old observatory.  This pit carries the land line from the Telstra microwave relay on the vantage point down to the homestead.  We did have a chuckle about the in-congruency of the nice neat cement pit cover and plastic pit liner sitting above the ground, with the cable then proceeding fully exposed down the hill side.  That said, the ground is basically ironstone, and the slope is quite steep, so we totally that understand Telstra didn't want to dig a ditch all the way.

 Here is John, one of the group up on the vantage point. You can see Telstra's big microwave relay tower and electronics cabinet here.  That extra 15m height at each end makes all the difference for being able to get line-of-sight back to the old observatory.

This is the view back towards the old observatory and village.  Neither are visible thanks to the low hill in the middle of the background.

My wife and daughter had a quick game of badminton on the hill top while we came to realise that we would have to run the link down the other side of the range.

 The trail-head map shows the village and Arkaroola Station.  We had been trying to get a link roughly along the Station Backtrack.  Now our attention was turning to the Acacia Ridge, where we knew there was good line of sight, but access would be more difficult, requiring a 1 hour walk up to the ridge line.

Instead of walking up to the ridge, we decided that it would be more fun to give John the chance to setup a temporary link between the two observatories, to get an idea of how to aim the dishes.

Unfortunately some the pole in the handy location was too fat for the mount:

So we attached it to the fence rail instead:

It's a bit tricky to tighten up, but we got there:

A quick visual inspection to see that the dish was more or less aimed in the right direction. We would come back later to trim the direction, only to discover we had it pointed perfectly to begin with.

It was back to the new observatory to pick a mounting point.  Lots of big I-section here, too large to clamp onto.  If you look at the full resolution image you can just make out the dish above the green-roofed building right of centre:

Unloading the gear...

Then applying a bit of bush ingenuity to make a mount that we could attach to:

And a few minutes later we had a nicely aimed dish:

Connect the battery, and aim it up, and obtain a very nice 55dB link margin at 300 mega-bits/second.

Due to the difficult access on the ridge, we didn't have enough time left to actually install the permanent link, although we did spend some time with Marg Sprigg to work out exactly where to mount the hardware at the homestead and village when we head back up in October.

We did however have a little time to enjoy some of the beautiful landscape, the following shot just 50 metres from our accommodation.  The natural history, amazing minerology of Arkaroola is a whole other dimension to explore.

Caleb found a few minutes to chat to the bar staff, and then it was time to head home.

Friday, August 15, 2014

Pure C firmware loader for RFD900 Radios

We are using the RFD900 radios in the Mesh Extenders, as described in previous posts.

The normal route for programming these is to use a python script or mono based GUI that comes with the SiK firmware.  However, for auto-updates on the Mesh Extender we need to run the update process from on the Mesh Extender itself.

It is possible to install python on the little OpenWRT boxes we use for the Mesh Extenders, however it isn't ideal on several fronts.

First, it is way bigger than the entire rest of the mesh extender distribution, and seriously bloats the upgrade bundles if we want them to be all-inclusive.

Second, for reasons I don't entirely understand, it isn't possible to run the python script headless in an /etc/rc.d script, which is basically a show stopper.

Third, the python firmware loader doesn't check if the firmware is already the same as what is on the radio.  This means that the flash would get worn out a little with each Mesh Extender software update, even if it doesn't change the radio firmware.

Fourth, you have to specify the baudrate of the radio.  It would be much nicer and safer to have it auto-detect.

Our solution is to write our own compact RFD900 firmware loader in pure C that addresses all these problems.

I have just finished the first working version, which can be downloaded from

It probably has some bugs, and might brick your RFD900 (although it might also help un brick it, too ;)

It is very easy to build and use:

To compile, just type make.  It is bland enough that it should work on most UNIX-like systems.  That said, I have only tested it on my Mac.

To run, you need to tell it the firmware file (in intelhex format) and serial port, e.g.:

flash900 radio~rfd900a.ihx /dev/cu.usbserial-A901G64G

When running, it will display something like:

Read 1760 IHEX records from firmware file
Trying to get command mode...
Checking if stuck in bootloader
Trying to switch to AT command mode
Switching to boot loader...
Got OK at 115200
Board id = $43, freq = $91
Erased parameters.
Checking if the radio already has this version of firmware...

Firmware differs: erasing and flashing...
Erasing flash.
Flash erased, now writing new firmware.
Range $f7fe - $f7ff

The Range line shows the memory range currently being verified/written, so you know how far along it is.  The flash gets verified as it is written, and the program will exit with an error if verification fails after writing.

If you want to force it to flash the radio even if the firmware is the same, add "force" to the end of the command line:

flash900 radio~rfd900a.ihx /dev/cu.usbserial-A901G64G force

While this little program is far from perfect, hopefully it will be of use to some people out there.

Thursday, August 7, 2014

Getting ready for National Science Week again

Australian National Science Week is coming up fast, and similar to last year, my family and I will visit some remote schools to encourage young people to think positively about science, and maybe consider including it in their future study and employment aspirations.

This year we will be visiting Hawker and Leigh Creek Area Schools, and the students from Marree Aboriginal School will make the (relatively) short trip down from Marree to Leigh Creek.

Apart from our existing love for this area, I purposely make my National Science Week plans to remote areas because they tend to miss out on a lot of the opportunities available in the cities and regional centres.  This is the tyranny of distance and isolation at work, which is also one of our prime motivators with the Serval Project.

It is pleasing that the South Australian Science Week Community Grants scheme has generously supported my efforts in this way for the past several years.  If you are a scientist, science teacher or communicator in South Australia and would like to contribute something to the festivities of Science Week in future years, they are a good port of call.

But back to National Science Week present...

I try to include something a bit different each time where the general public can get involved in some way.  This year that is establishing a permanent wireless communications link between the Arkaroola Village and the Arkaroola Homestead area where the Arkaroola Wilderness Sanctuary plans to setup a research facility, which are several kilometres apart, and separated by some spectacular and rugged hills and ridges, some of which looks just like this:

Here you can see the wireless communications gear we will be using that arrived this morning from the nice people at CityTechnology:

In the future, this will allow for high-bandwidth real-time communications to support future research activities in the sanctuary.  But right now, it is a great chance to join us at Arkaroola to be part of the team who are setting up and testing this facility, and explore parts of the sanctuary that are not normally easily accessed.  Arkaroola will be providing us with transport to the ridges and locations where we need to setup the links.

So if you would like a bit of an outback adventure with some science content, hop over to the information page on the National Science Week website and register your interest.  Of course you don't have to just join in with us, you can enjoy many of the other great things that Arkaroola has to offer, including fantastic astronomy, scenic flights over what Hans Heysen described as "the bones of the earth laid bare", and much more.  You will also be close to some of the world's oldest fossils of complex life.

Monday, August 4, 2014

Problems with SanDisk Cruzer Fit flash drives

For the Mesh Extender we need physically very small USB memory sticks for the Rhizome data store.

We have had problems with these in the past: some Verbatim ones wouldn't mount reliably at boot.

So we switched to the SANDisk Cruzer Fit.

However, those drives are not without their own problems.

In fact, they have a really nasty habit of going permanently read-only under certain circumstances.  This is fairly well documented on the internet, and SanDisk have known about the problem for at least a couple of years, e.g.:

It turns out that one of those circumstances is when installing a Mesh Extender upgrade bundle.

We have had two more fail within the space of an hour today, in addition to others that have failed in the past.

We have contacted SANDisk to ask if they have fixed the root problem in their later drives, and are awaiting a response.  We have also got in touch with them to see about getting replacement drives.  We have offered to show them our use case that triggers the units to go read-only. Right now they signs aren't good that that they will sort things out, or even honour their statutory obligations, but we will keep you posted.

In the meantime, until SanDisk asserts and we can verify that the problem with these drives has been corrected, we strongly recommend against buying any SANDisk USB memory sticks.