What just happened? Murex Robotics, a competitive robotics team based at Phillips Exeter Academy in New Hampshire, claims to have developed the smallest and most affordable network switch ever created. This squarish device is about three fingers wide and costs just $7.
Called the mrxSwitch v2.0, the device provides five 100Mbps Ethernet ports in a minuscule 44.9mm x 42.2mm footprint. That speed is obviously not breaking any records, but it’s still sufficient for the kind of machines it’s designed for. Most network switches this small are reserved for highly specialized embedded systems, but Murex built theirs specifically for use in underwater rovers and robotic subs.
“The mrxSwitch V2 is the smallest networking switch in the world and outperforms all commercially available options in size and cost. Its applications include but are not limited to embedded systems, ROVs and AUVs, consumer electronics, DIY projects, and other space-constrained networking applications,” notes the team.
The tiny board allows onboard computers like Raspberry Pis or NUCs to interface with all the cameras, motors, and other tools needed to operate an unmanned undersea vehicle. With its space-saving 4-pin Molex PicoBlade connectors instead of bulky RJ-45 ports, it’s perfectly sized for the cramped interior of a waterproofed robot shell.
The mrxSwitch uses a high-performance unmanaged switch IC and external magnetics to cut size and costs to the bone. Under the hood, the device has a 4-layer PCB to minimize noise, Bob Smith termination for clean signal integrity, and meets all IEEE 802.3 Ethernet compliance. It can accept an input voltage as high as 15 volts, converting it to the 3.3-volt level required by its internal components.
Building such a compact switch wasn’t easy. The largest component, a dual-port transformer, is barely bigger than a knuckle, and the switching chip is smaller than a fingernail. This incredibly dense layout allowed Murex to shrink the board size by 30% compared to their previous version, while also cutting costs by 15%.
The students didn’t just make the mrxSwitch tiny, they made it affordable too. While most ultra-compact switches can cost well over $100, Murex’s build costs only $7, thanks to basic off-the-shelf parts and their custom-designed PCB.
The project is fully open-source, allowing makers and hardware tinkerers to study the design or build their own miniature switch. You can find the board layout files from this GitHub link, while the blog on the first iteration of the switch can be found here.
