ESP32 Firmware & IoT for Water Utility Telemetry

Water utility RTUs sit in flooded pits, chambers with no mains power, and reservoir sites at the edge of cellular coverage. We build ESP32-based telemetry units that survive that environment, speak the analog and Modbus protocols your existing instruments already output, and buffer locally so a dropped link never becomes a lost flow total or a missed turbidity alarm.

Challenges specific to Water Utilities

• Flow totalisers drift after comms gaps

  Pulse-output meters keep counting during an outage, but a naive uplink resends only the latest reading, so the billed/abstracted volume loses every litre that flowed while the modem was offline.

• 4-20mA pressure loops read noise as alarms

  Pump-start surges and water hammer spike the loop current, and without per-channel debounce and slew limiting the RTU fires false low/high-pressure alarms that erode operator trust in the system.

• Reservoir sites have no mains and weak signal

  Level sensors on remote reservoirs run off solar and a small battery at the fringe of cellular coverage, so an always-on TCP modem flattens the battery and the site goes dark for days at a time.

• Turbidity events are missed between samples

  Slow polling intervals chosen to save power mean a short turbidity spike from a main break or backwash passes entirely between two samples, and the regulatory exceedance is never recorded.

• Modbus instruments use clashing register maps

  Each magflow, analyser, and pressure transmitter exposes a different Modbus register layout, scaling, and byte order, so one firmware build rarely drops into a mixed brownfield site without rework.

How GizanTech solves them

1. Pulse-accurate flow accounting. We count flow-meter pulses in a hardware ISR with a 64-bit non-volatile totaliser in NVS, so the cumulative volume is reconstructed exactly after any reboot or comms gap and reconciles with the meter register.
2. Conditioned 4-20mA acquisition. Each loop is read through a precision sense resistor and oversampled, then median-filtered with configurable slew and debounce so pump surges and hammer transients no longer trip false pressure alarms.
3. Solar-aware duty cycling. On reservoir sites the ESP32 deep-sleeps between samples and wakes the cellular/LoRaWAN radio only to drain the buffer, holding average draw low enough to run indefinitely on a small solar-plus-battery node.
4. Event-triggered turbidity capture. Turbidity is sampled fast and compared against rate-of-change and absolute thresholds locally, so a spike forces an immediate uplink and a high-resolution burst instead of waiting for the next scheduled poll.
5. Per-instrument Modbus profiles. A JSON-driven Modbus RTU master maps each device's registers, scaling, and word order at config time, so one firmware image serves mixed magflow, analyser, and transmitter fleets without a recompile.