Now that the five sensors were detecting and feeding metrics to the service and I was able to see the baseline forming, I began to think now I might induce failure. I certainly didn’t want to cause a failure in an expensive GPU or an important and expensive home system in my house. When I started the PoC, I imagined building a complex Rube Goldberg machine and impressing the world at my craftiness. I started by removing the sensor from the furnace. I thought an alarm might be induced by the complete absence of any vibrations or temperature variations which should’ve been in the baseline - nothing. No alarm was triggered. I deduced that the sensors don’t cover below threshold situations as I’d thought.
Next, I thought I’d induce some heat into the metal contact plate at the bottom of the sensor with the soldering iron. That worked to a degree, pun intended, but then the sensor appeared to start to melt, and the temperature didn’t rise fast enough. So not wanting to destroy the sensor, I abandoned that approach.
In the end it came in as a much simpler solution. I wanted something that I felt could run for a fairly long time unsupervised and with which I could introduce the desired change in metrics which would trigger an alarm.
My old, but trusty corded drill came to the rescue. Because it was a standard drill I’d previously bought an attachment to make it like a hammer drill, in order to drill into concrete and rocks. It serves the purpose well. When I ran it for a short time, it still didn’t induce the type of vibrations I wanted, so I added a key chuck to the mix. Given its shape and obvious imbalance, I clamped the drill to my cabinet and zip tied the sensor to the drill and the trigger to the “On” position.
It didn’t take too long to induce an alarm.