Spot a fake DS18B20 on a Raspberry Pi: family-code check, sysfs CRC test, and ice/boil calibration against the datasheet. 3 of 7 probes in one batch were counterfeits, drifting 1.5–3.5 °C.
DS18B20 parasite power vs 3-wire on long cable runs: why parasite power fails past ~3 metres on a 1-Wire bus, the physics behind the voltage collapse, and what 3-wire + 4.7k pull-up measured over 24 hours on the operator's 8-sensor bus.
How I ran my old RRDtool logger and its SQLite replacement in parallel for months — why you tee the reads instead of double-polling, and how to set a real cutover test before a monitoring-system migration.
DHT11 accuracy after 18 months of continuous logging on a Raspberry Pi: 26,318 rollup rows, 38% below the datasheet's 20 %RH floor, and where the part stops being usable.
Why asyncio does not make 1-Wire faster, and the collector pattern I actually run: per-plugin loops, to_thread for blocking buses, and one batched SQLite writer.
DS18B20 CRC errors on a short, correctly-terminated 1-Wire bus: eight probes on 2-3 m of ribbon cable, a correctly sized 4.7k pull-up, and a persistent failure rate that the wiring does not explain — tuned toward the phrase people actually search.