Powering the M2M & telemetry revolution
Data from M2M and telemetry devices can be of great benefit to business and how we expect the sector to grow, but one question to be answered is how is it going to be powered..? For cars, vending machines and electricity meters this isn’t much of a concern, but there are a large number of applications, such as those in the water/waste water sector or for tank level monitoring in the fuel and chemical sectors, where there is no power or connecting to power is relatively costly.
In many cases telemetry and M2M devices need to operate maintenance free for years and years and this means a good reliable source of power is needed. It also means the technology in the device needs to be able to deliver enough power for the devices to communicate reliably. It is this kind of challenge that faces the hardware developers. Using batteries is one option, though the right chemistry must be chosen to give a low self discharge rate, and unfortunately the chemistry that has this feature suffers as it is generally limited in the maximum amount of power it can deliver and for how long. It is well understood that GPRS is attractively priced for M2M applications, but when communicating using GPRS over the GSM networks there are technical difficulties that must be overcome in order to maximise both signal strength and battery life. These difficulties are not insurmountable as proven with devices such as the Metron2 and the Metron ATEX, but it is most certainly a challenge.
There are applications that don’t suit batteries. Perhaps more power is needed, or a longer time between battery replacements is preferred, and this turns our attention to energy harvesting. A good example of how solar energy can be used is within the cryogenic gas field. Distribution of cryogas is very expensive and part load returns are very costly and potentially damaging to the plant into which they are being returned. Having a telemetry device that can be polled makes it easy for the planners to quickly see which nearby tanks would benefit most from a quick "top up."
This has led to Powelectrics developing a solar powered GPRS capable telemetry system that it always on and therefore pollable. In order to maximise battery life and solar charging potential, or to help recover a battery in poor condition then intelligent charging circuitry is required. As well as this it is important that the charge rate is adjusted according to the temperature of the battery.
But what’s next..? There will be applications where there is no sun because the devices are underground, or when a solar installation would be prone to vandalism. How the M2M and telemetry revolution will be powered presents some interesting questions as well as exciting opportunities to those that are able to harvest the technology.