Embedded Compute

Average current, not peak MIPS, decides how long a sensing node lives. This note walks through the arithmetic for four common duty cycles, shows where datasheet sleep figures mislead, and gives a measured comparison of eight candidate parts under an identical one-per-cent duty workload with the same radio and sensor attached.

Second-sourcing every line is unaffordable; second-sourcing nothing is how a programme stops. We classify BOM lines by substitution cost rather than by unit price, and show on three real designs that qualifying alternates for the top twelve per cent of lines covered eighty per cent of the historical shortage exposure.