Never worry about your water tank again. A solar-powered sensor on the rooftop, a quiet hub on the wall, and smart water monitoring that keeps working — even when the internet doesn't. Long-range LoRa (RYLR998) to an ESP32 hub, local web UI, Home Assistant via HACS, optional cloud PWA. Open at the core.
Custom circular TX PCB and current-production PETG enclosure (REV 2.2, May 2026) — tested through Delhi summer at 45°C ambient.
👉 tanksync.smartghar.org/firmware/
No esptool, no Python, no CLI. Plug your board into USB, click Install, the browser does the flashing through WebSerial. Works on Chrome/Edge desktop. Takes ~45 seconds per board.
Most "smart tank" products treat the cloud as the product. TankSync treats reliability as the product — and the cloud as an optional layer of polish on top.
- Works fully offline. Hub keeps showing levels, lighting the LED ring, and beeping on overflow — even when your WiFi, your ISP, or our cloud is down. Local operation is the default; cloud is opt-in.
- Long-range LoRa, no rooftop WiFi. Sensor talks to the hub over 865 MHz LoRa — through concrete walls, between floors, across a property. Up to 5 km line-of-sight. The rooftop doesn't need WiFi. Ever.
- Solar-powered transmitter. Mounts on the tank lid. Charges in regular daylight, runs on a single 18650, deep-sleeps between readings. Months of autonomy. No wires to the tank.
- Home Assistant native. Auto-discovery via MQTT plus a dedicated HACS integration — every tank shows up as an HA device with live sensors, fill events, and editable settings.
- Open at the core. Firmware (AGPL-3.0), hardware (CC BY-SA 4.0), schematics, BOM, and flashing tools are all public. Self-host it. Fork it. Modify it. Audit it. No vendor lock-in.
- Built for Indian realities. Designed and tested through Delhi summer (45 °C ambient). UV-stabilised PETG, IP65 sealing, monsoon-ready. Engineered for terrace tanks, high-rise apartments, thick walls, and unreliable connectivity.
LoRa 865/915 MHz (up to 5 km, through walls)
==============================================>
TRANSMITTER HUB (RECEIVER)
ESP32-C3 SuperMini ESP32 DevKit
+ JSN-SR04T Ultrasonic + RYLR998 LoRa
+ RYLR998 LoRa + SH1106 OLED
+ 18650 + solar + WS2812 LED ring
+ WiFi (optional)
|
+-----------+-----------+
| |
MQTT (TLS) Local web UI
| 192.168.x.x
+---------+---------+
| |
Home Assistant Cloud dashboard
(HACS integration) (optional, hosted)
| Component | Part | Approx cost (INR) |
|---|---|---|
| Receiver MCU | ESP32 DevKit v1 | ₹300–400 |
| Transmitter MCU | ESP32-C3 SuperMini | ₹200 |
| LoRa module | REYAX RYLR998 (×2) | ₹650 each |
| Ultrasonic sensor | JSN-SR04T (waterproof) | ₹350 |
| Display | SH1106 1.3" OLED I²C | ₹250 |
| Battery | Protected 18650 + holder | ₹200 |
| Solar charger | CN3791 MPPT module | ₹120 |
| Boost converter | MT3608 3.7 V → 5 V | ₹50 |
Total: ~₹3,800-5,200 per complete system (one hub + one tank). Per-tank addition: ~₹1,500.
📐 Detailed wiring + power chains → 📋 Full BOM →
👉 tanksync.smartghar.org/firmware/
Plug your board into a USB port, pick the right card (Receiver Hub or Transmitter), click Install. Done in ~45 sec.
Download the latest .bin from Releases.
# Receiver (ESP32 DevKit)
esptool.py --chip esp32 -b 460800 write_flash 0x10000 tanksync-receiver-rx-vX.Y.Z.bin
# Transmitter (ESP32-C3 SuperMini)
esptool.py --chip esp32c3 -b 460800 write_flash 0x10000 tanksync-transmitter-tx-vX.Y.Z.binPrerequisites: ESP-IDF v5.4+
# Receiver Hub
cd firmware/Receiver-ESP32-DevKit
idf.py build
idf.py -p /dev/ttyUSB0 flash
# Transmitter
cd firmware/Transmitter-IDF
idf.py set-target esp32c3
idf.py build
idf.py -p /dev/ttyACM0 flash- Hub starts in AP mode → connect to
TankSync-XXXXWiFi from your phone - Captive portal opens (or visit
192.168.4.1) - Configure home WiFi + (optional) MQTT broker + LoRa settings
Two surfaces — pick either, or both. They show the same data.
Left: the PWA at tanksync.smartghar.org — works from anywhere. Right: the hub's local web UI — works fully offline. Full walkthrough in the Wiki.
- Transmitter pairs over the air — hold its
BOOTbutton for 2 sec, hub LED turns green when paired
More photos + STL files for the case + schematics + 3D STEP models: hardware/.
Two routes — pick whichever fits your setup:
- Native MQTT auto-discovery — the hub publishes auto-discovery topics; tanks appear in HA as sensor entities with zero setup beyond pointing HA at the same broker. Read-only.
- HACS integration: SmartGhar — full bidirectional control. Every tank is an HA device with grouped Sensors / Events / Configuration / Diagnostic entities, plus a hub device with buzzer + LED controls. Capacity, sleep interval, samples-per-wake are editable from inside HA and ride the same MQTT command channel as the PWA, so both stay in sync.
HACS repo: github.com/Techposts/smartghar-homeassistant · Full setup + entity reference: HACS Integration wiki page
This is the open-source TankSync firmware + hardware mirror. The hosted cloud dashboard (PWA at tanksync.smartghar.org) is a separate proprietary product that adds:
- Remote access from anywhere (no port forwarding)
- Push notifications to your phone
- Multi-tank history + insights
- QR-code device linking
- Multi-hub fleet management for societies, farms, hotels
The firmware works fully without the cloud — local web UI on the hub gives you tank levels, settings, OTA updates, Home Assistant integration. Cloud is opt-in convenience, never a dependency.
| Component | License | What this means |
|---|---|---|
Firmware (firmware/) |
AGPL-3.0 | Free for personal + community use. Commercial users who modify and distribute must also open-source their changes under AGPL. |
Hardware (hardware/) |
CC BY-SA 4.0 | Attribution + ShareAlike. Build it, sell it, modify it — credit the source and share-alike. |
| HA Integration | MIT (separate repo) | Frictionless for HA ecosystem. |
Why AGPL on firmware? It keeps TankSync open for hobbyists and HA users while preventing commercial vendors from repackaging the firmware into a closed product. If you want a non-AGPL commercial license for embedded use, reach out to the maintainer.
Issues and PRs welcome. Read the wiring guide before opening hardware-related issues.
Ravi Singh (@ravis1ngh on YouTube) — solo-building open-source home infrastructure in India under the TechPosts Media / SmartGhar banner. Design, firmware, hardware, PCB layouts, and 3D-printed enclosures — all done in-house.
TankSync is part of the SmartGhar ecosystem (smartghar.org) — calm, local-first smart-home infrastructure engineered for real-world Indian deployments.