When it comes to management and maintenance of smart-cities and agriculture in general, one can’t help but come across Lund based start-up Sensefarm. Offering a cloud-based analysis service on data collected by their LoRaWAN sensors implemented in the ground, they assist contractors, property managers, and researchers in managing trees and plants and helping them optimize agricultural yields by assessing soil moisture, temperature, and precipitation.
“Everything worked fine until we started to lose communication with the sensors in the field for unknown reasons.”
Sensefarm customers almost always need to follow environmental parameters in real-time locations far from the offices, and not easily accessible. This creates a challenge in the transportation of sensors and their maintenance, especially from the battery life perspective. Besides the size and robustness, it needs to be taken into account that the sensors may be air-transported (avoid large D-cell batteries!) and require long battery life because they can´t be replaced. You might say that battery life is something one takes for granted until you reach the point where you have to go out and check each of the already implemented sensors, just to realize that the only thing missing is the power. As trivial as it seems, even the most straight forward systems depend on its source of energy to be stable and reliable.
Not only did the Sensefarm sensors suddenly stop transmitting, they even started transmitting false information leading to questionable results. There was no obvious reason whatsoever as to why these sensors started to fail. And more importantly, there was absolutely no way to find out. Speculating about whether it might have been an unknown bug that prevented the sensors from going into sleep mode or whether there was simply a miscalculation of the expected battery life span, Sensefarm’s only unsatisfactory option was to drive to the different locations, and replace their batteries at a very high cost – a solution far from sustainable and efficient.
“Having a tool like Otii that checks the power states over weeks to catch software bugs not visible when a debugger is attached, and quality checking the batteries with Otii Battery Toolbox as in this case is simply a must.”
Making use of Otii Battery Toolbox, Sensefarm concluded quickly that the real capacity wasn’t far from the specification and wasn´t the source of the problem, but rather an abnormality in battery behavior after a couple of thousands of transmissions. The Otii graphical user interface clearly showed that their batteries lost the complete capacity for a few cycles before returning to the normal voltage level and full capacity. Based on these findings, Sensefarm was able to investigate further and eventually found the actual source of the problem – it seemed that short circuit metal bridges formed inside the battery, and once burned out the battery continued to work as expected.
“The knowledge of the root cause of the problem cannot really be stated in money. Selling a sensor that sometimes and randomly might fail is simply not an option.”
Being able to eliminate this underlying cause of the frequent battery failure did not only put an end to randomly replacing the batteries but also allowed Sensefarm to restructure its entire support business model. With the Otii Battery Toolbox batteries can now be thoroughly tested before implemented giving Sensefarm the assurance and security that these batteries indeed work well with their sensors. Assisting them in solving this issue and helping them to exploit their full potential is, also for us, an absolute success and the very reason we go to the office every day.
Also, maybe the knowledge of the root cause can actually be stated in money – check out our price plans at our distributors for the Otii Arc and Otii Battery Toolbox.