Engineers are being asked to connect absolutely everything to a network. The network protocol of choice is Ethernet or one of the myriad variations. Some of these assignments can look great on paper but suffer serious setbacks once realized in the modern world.

The original designers of the Ethernet could not have imagined what we have done with their “baby.”

To be fair, the vast majority of Ethernet runs require no special protection. The first electrical component behind most RJ-45 Ethernet jacks is an isolation transformer that will provide some protection. This, paired with the ESD protection built into most Ethernet PHY transceiver IC’s, provides adequate protection in most home and office environments.

he problem is the low percentage of Ethernet ports that are exposed to more serious threats. Long cable runs inside buildings become long-wire antennae that can couple energy from nearby lightning strikes into the network. Those “antennae” are even better at collecting lightning energy if they are run outdoors to kiosks, or up to rooftop or pole-top security cameras.

When reliability issues first surfaced, circuit protection companies developed protection “dongles” that provided additional ESD overvoltage protection.

As data rates climb and with the advent of PoE, custom solutions are needed and the “one-size-fits-all” dongle approach is often inadequate. PoE brings on even more issues as the DC voltages present can trip the overvoltage protection in dongles designed only for the 2V Ethernet signal. Gigabit data rates can suffer significant data errors due to the capacitive loading of protection schemes designed for 10Base-T or 100Base-T networks.

The SenseLamp is an ultra-low cost (less than 30GBP/45US$), WiFi enabled sensor platform that is easy to build, easy to deploy and fully open source. A SenseLamp is a lamp shade that can be remotely controlled and gathers temperature, humidity, light-levels and motion data.