Open hardware reference for the TankSync LoRa water-tank monitor. All files in this
hardware/tree are released under CC-BY-SA 4.0 — you can build, modify, and resell them; derivative designs must stay open under the same license. Firmware is AGPL-3.0 (seefirmware/).
TankSync is two boards talking to each other:
| Board | Role | Power | Where it lives |
|---|---|---|---|
| TX (Transmitter) | Ultrasonic level sensor + LoRa uplink, one per tank | Solar + 18650 Li-ion | On / inside the tank lid |
| RX (Receiver / Hub) | LoRa gateway + Wi-Fi / MQTT bridge + OLED + LED strip | USB-C 5 V | Indoors, plugged into a wall adapter |
A single RX hub talks to up to 6 TX nodes over 865 / 868 / 915 MHz LoRa (region-selectable in firmware). The RX publishes readings to a local MQTT broker or to the SmartGhar cloud — your choice.
| Path | What | Format |
|---|---|---|
BOM.csv |
Complete bill of materials for both boards + the enclosure | CSV |
pcb/ |
Schematics (PNG + SVG), pin assignments, 3D STEP files, system block diagram | PNG / SVG / PDF / STEP |
cases/circular-v1/ |
Current production case — circular PETG, integrated solar lid, BSP-threaded sensor mount | STL |
cases/rectangular-v10/ |
Legacy v1.0 case — rectangular, older PCB form factor (kept for reference) | STL |
photos/ |
Photos of the assembled PCB and finished case (9 images, see below) | JPG |
 |
 |
| Bare PCB, top side | Hand-soldered, top side |
 |
 |
| Bottom side (passives + Schottky) | Angled view, modules stacked |
 |
 |
| Lid with integrated solar pocket | Closed assembly side view |
 |
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| BSP boss in test tank lid | Close-up of nut + thread |
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|
| Opened unit, SMA antenna variant |
Each subfolder has its own README.md explaining what's inside and how to use it.
flowchart LR
TX[TX node<br/>solar + 18650] -->|LoRa 865 MHz| RX[RX hub<br/>USB-C]
RX -->|Wi-Fi + MQTT| Broker[(MQTT broker<br/>local or cloud)]
Broker --> HA[Home Assistant]
Broker --> PWA[TankSync PWA]
All modules share a common ground. One TX per tank; one RX hub per property; up to 6 tanks per hub. Broker is either your local Mosquitto, or mqtt.smartghar.org if you use the free cloud tier.
- Print the case files from
cases/circular-v1/(PETG, 0.2 mm, 30 % infill — see that folder's README). - Order parts from
BOM.csv. - Get the PCBs fabbed from
pcb/rx-schematic.*+pcb/tx-schematic.*(or send the project files to JLCPCB / PCBWay). - Solder, populate the BOM, then flash the firmware → easiest path is the browser flasher at tanksync.smartghar.org/firmware (Chrome / Edge desktop, USB-C cable, no toolchain install).
- Power on the RX → connect to its
TankSync-Setup-XXXXWi-Fi AP → configure Wi-Fi + MQTT. - Hold the TX boot button 5 s → it joins the RX automatically via LoRa pairing mode.
The TankSync wiki has a step-by-step build guide: github.com/Techposts/TankSync/wiki.
- Firmware (anything under
firmware/) — AGPL-3.0 - Hardware (schematics, PCB layouts, STL cases, BOM, this folder) — CC-BY-SA 4.0
- Brand — "TankSync" and "SmartGhar" are trademarks of Ravi Singh / TechPosts Media; you can build and sell the open-hardware design but please don't use the brand names for commercial derivatives.
Patches welcome via pull request. If you ship a commercial product based on this design, the AGPL + CC-BY-SA terms require you to publish your modifications under the same license.