ESP32 + EC/pH sensor rig

DIY reservoir monitoring: an ESP32, an EC probe, a pH probe and a temperature sensor for under $50. Genuinely useful for spotting drift before it becomes damage.

Tier 3 by definition: the convenience layer, and the first thing to fail. The design rule is that the garden must not care when it does — sensors observe, they never gate the watering.

Start here — 3 curated links

ESP32 hydroponics monitor — proven build Guide github.com

Open firmware with calibration routines that actually hold — start from a fork, not from scratch.
Cheap EC probes — what you get for $10 Article scienceinhydroponics.com

Honest accuracy testing of the AliExpress probe tier against lab meters.
Solar-powered LoRa sensor node design Guide youtube.com

The off-grid variant — panel sizing, deep sleep and battery chemistry for outdoor nodes.

entry added 2026-06-12 · links last verified 2026-06-12 · 3 links