The summary.
ESTABLISH WHAT DECISION THE DATA CHANGES BEFORE DEPLOYING ANYTHING
Data nobody acts on produces nothing, and every reading costs transmission, storage and attention.
Compare against doing nothing and against a manual process — connected devices carry ongoing cost that a one-off measurement does not.
THE ONGOING COST USUALLY EXCEEDS THE HARDWARE
Connectivity, platform charges, batteries, maintenance and support, multiplied by the fleet and by years.
IF A SITE VISIT COSTS MORE THAN THE DEVICE, THE DEVICE MUST NEVER NEED ONE
Design for never being touched again.
SENSOR PLACEMENT AND DRIFT DETERMINE WHETHER DATA IS TRUE
A temperature sensor in sunlight measures the sunlight, and deployed sensors slowly become wrong with nothing indicating it. Plan calibration or replacement.
A WRONG ACTION CAUSES PHYSICAL CONSEQUENCE, UNLIKE A WRONG READING
Enforce limits on the device itself, define the safe state for every actuator, and never depend on a network connection for a safety function.
Confirm by sensing the result — commanding is not the same as achieving.
HEAT, DUST, HUMIDITY AND POWER INSTABILITY ARE ROUTINE HERE
Equipment rated for milder conditions fails.
