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Geysital

Smart Geyser Control App

Smart geyser automation: a React Native app that controls a connected water heater over Bluetooth or Wi-Fi — live and target temperature, power, gas / electric / hybrid source priority and daily heating routines — backed by Node.js, MQTT and Embedded C firmware.

Case study (PDF)
Geysital control screen: full control at a glance
Geysital case study cover: the app next to a connected geyser
Geysital Bluetooth discovery: connected device
Geysital dashboard: all your geysers in one place
Geysital device setup: Wi-Fi or direct Bluetooth

Geysital control screen: full control at a glance

My role

Senior Full-Stack Developer

Stack

7 technologies

Built with

React NativeNode.jsExpressMQTTBluetooth LEWi-FiEmbedded C

01 — Overview

What it is

Geysital is a smart geyser automation system that modernizes traditional water heating by giving users complete control through a mobile app. The app connects to the geyser so people can monitor, control and automate heating without standing at the appliance.

Core capabilities cover power, live temperature, target and range, gas / electric / hybrid source selection, source priority, routines, and dual connectivity over Bluetooth Low Energy and Wi-Fi.

02 — Problem

What was missing

Traditional geysers need manual operation and give little visibility into the heating process. Users walk to the appliance, check the water temperature by hand, and decide when to stop heating — inconvenient, and it can waste energy.

  • Manual ON/OFF at the appliance
  • No live temperature on a phone
  • Limited target temperature control
  • Hard to choose Gas, Electric or Hybrid
  • No routines around daily use
  • Little feedback on device state

03 — Approach

How I approached it

  1. 01MonitorLive temperature, power, heating and connection status first.
  2. 02ControlOne-tap ON/OFF and a visible target temperature slider.
  3. 03ConfigureGas, Electric or Hybrid, plus source priority and safe bounds.
  4. 04AutomateRoutines that heat around the day instead of every manual tap.

04 — Build

How it’s built

Two complementary paths sit under the same app. Bluetooth is nearby and local; Wi-Fi carries the IoT path through the backend and MQTT. Both meet in Embedded C firmware on the geyser.

Nearby · Bluetooth LEApp → BLE → Geysital device
  • • Scan and pair
  • • Device name, ID and signal strength
  • • Open the dashboard without the backend
Connected · Wi-Fi / MQTTApp → Backend → MQTT → Device
  • • Remote-oriented control
  • • Node.js + Express APIs and device services
  • • Lightweight MQTT messaging to the device
React NativeCross-platform mobile app and UI
Node.js + ExpressBackend APIs and device services
BLE + MQTTLocal radio and lightweight IoT messaging
Embedded CFirmware: temperature, commands, heating, comms

05 — Impact

Results & impact

3Heating modesGas, Electric and Hybrid, with source priority.
2Connection pathsBluetooth for nearby pairing, Wi-Fi + MQTT for remote.
6Core capabilitiesControl, visibility, flexibility, efficiency, automation, connectivity.
  1. 1Turned a manual appliance into a connected one: users switch the geyser on and off from their phone with live connection status.
  2. 2Made heating visible — the current temperature sits next to the target (e.g. 29°C live vs a 45°C target), inside a safe 20–75°C range.
  3. 3Put energy choice in the user's hands with gas, electric and hybrid modes plus source priority.
  4. 4Added daily routines, e.g. 50°C electric at 6 AM, 45°C on gas at 7 PM, standby at 10 PM.
  5. 5Designed dual connectivity: nearby control over Bluetooth, and remote control over Wi-Fi through a Node.js + Express backend and MQTT.
  6. 6Made pairing clear: add by ID, scan, and helpful empty states instead of silent failures.
Read the full case studyPDF · 7 pages

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