by Ground Electronics

The datacentre-in-a-box for high-performance-computing and cloud software development, testing, and education

View all updates May 31, 2018

Backplane, Raspberry Pi, and Ethernet Switch Assembly

In the previous update we took a look at how the 32+1 node Circumference 100 has evolved from the very first prototype — which used a great deal more cabling and an external power supply — to a highly integrated solution built around a custom backplane. However, we didn’t really give any detail on the backplane itself and how Raspberry Pi compute nodes are connected.

The above stop frame animation shows clearly how a stack comprised of 8x Raspberry Pi boards plus backplane is assembled, with each compute node securely attached to the backplane via high quality Samtec connectors, and separated by four M2.5 black nylon stand-offs. This sub-assembly is then secured to an acrylic plate which has had two 5-port Gigabit Ethernet switches attached.

With the C25, two Ethernet cables run direct to the UDOO dual-gigabit Ethernet adapter. While with the C100, there are 8x Ethernet cables that run into the base and connect into an additional two 5-port switches, which in turn are connected to a dual-gigabit Ethernet adapter. In both cases the only other connections are 1 or 4 each of USB cables for control, and 6-pin PCIe connectors for power.

So as you can see, it’s a pretty neat solution in terms of cabling.

Andrew and the Circumference Team

$8,535 raised

of $40,000 goal

21% Funded Time Expired
Jun 28 2018

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Circumference 25 Enamel Badge

The same C25 metal and vitreous enamel badge as can be found on the front of the 8+1 node cluster, albeit with a pin fastener. Wear your Circumference support with pride!


Circumference 25

C25 8+1 node cluster campaign pricing.


Circumference 100

C100 32+1 node cluster campaign pricing. Includes custom logo etched on the wood veneer front panel.


Ground Electronics

Ground Electronics is a supplier of open source hardware kits and accessories, and is the manufacturing division of AB Open, an open source and technical communities consultancy that specialises in embedded and wireless systems. AB Open has many years experience working with semiconductor companies, component distributors and equipment vendors, developing technology demonstrators and consulting on all matters related to open source hardware and software.

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Jerome Dineen

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