Experiments with mesh networks

I’ve started building a mesh network in C++, it’s a small library intended for use on Raspberry Pi and Arduino. Currently I want to support one kind of radio, an NRF24L01+ which you can get pretty cheap on ebay.

These radios provide us with a Layer 1 (Physical) of a OSI network but to build a functional mesh network we need a Layer 2 (Data link, addressing) and Layer 3 (Packets), once we have those two layers we need a Layer 4 (Segments, connection management) then onto the final layer, Layer 5 (Data).
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HotPi Update

The stock from the kickstarter has run dry a long time ago and we’re now shipping a slow methodical number of units via the pi hut.¬†We’re running out of green boards now, all new boards are red, and new orders will start to come through that way.

I recently published a new page for the HotPi and the new User Manual. You can get both over on this page.

I’m going to be designing a new small board or two which will fit in to the range of HotPi products. This should take 1-2 months to get back from manufacture and I’ll keep the blog updated along the way.


Turning Photographs into Wireframes, VisualSFM on CentOS6

DL390 G5For the purposes of performing a highly detailed capture of various historical monuments, which are local to me, I purchased a big fat server with oodles of processing capability. The system itself is a 2.83GHz Dual Quad Core Xeon HP Proliant DL390 G5 – not a bad bit of iron. It’s loud, it’s warm but it’s very very quick. Added to that a couple of 1Tb 2.5″ disks and a nVidia 210 with 1Gb of graphics memory. Once you’ve got this kind of hardware you’ve got to put it to good use. First thing for my project was to build up an appropriate workflow for using VisualSFM and Meshlab on the machine. These are tools which perform a “photogrammetric” reconstruction. VisualSFM is difficult to get working, It is dependent on packages which each have their dependencies, it’s also poorly documented generally so I wanted to ensure that my struggle helps out others. CentOS 6 was my OS of choice, I usually use this on a server as it’s pretty low maintenance once it’s configured and support stretches on and on. After a day or so of software builds (btw make -j8 is fantastic) I managed to get it working. I’ll share the binary/source RPMs that I’ve rebuilt and links to the other bits of the entire workflow. Along with a guide on how it is done.
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After a long time, I’ve decided it’s time I rebooted my blog, rebuild my home page and show off some of the things I’ve been working on over the last 2 or so years since I last blogged.

I decided to begin with a clean slate, starting afresh with all new content, and an all new site design and layout.

So here it is Quick and Dirty Hacks Rebooted.