About This Project
A smooth-swing, sound-reactive lightsaber with swappable blade colors. Arduino-compatible.
LoRa-connected soil sensors designed for small farms across India and Southeast Asia. Each node is solar-powered and rated for 3 years of continuous operation without battery replacement. The sensor array communicates via LoRaWAN to a central gateway that pushes data to any MQTT-compatible dashboard.
All hardware designs are released under CERN-OHL-S. The KiCad schematics, STEP models for the weatherproof enclosure, and the firmware source (written in Rust for the nRF52840) are all available in the project repository. We want farmers and agricultural researchers to be able to build, modify, and manufacture these sensors without any licensing restrictions.
Campaign Video
Build Gallery
3D Model
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PCB Design
Open Source Files
CERN-OHL-PBill of Materials
10 components| Component | Qty | Source | Est. Cost | ||
|---|---|---|---|---|---|
| Ceramic filter element | 1 | Potters for Peace / local kiln | ₹295 | ||
| UV-C LED array (4x 275nm) | 1 | LCSC / Mouser | ₹520 | ||
| Bamboo composite housing | 1 | Local workshop | ₹235 | ||
| Solar charge controller (MPPT) | 1 | AliExpress / local | ₹285 | ||
| 12V 6Ah LiFePO4 battery pack | 1 | EVE Energy / local | ₹460 | ||
| 10W solar panel | 1 | Global sourcing | ₹270 | ||
| Flow rate sensor (YF-S201) | 1 | LCSC / AliExpress | ₹92 | ||
| TDS sensor module | 1 | AliExpress / local | ₹75 | ||
| PCB + through-hole components | 1 | JLCPCB / hand-solder | ₹100 | ||
| Silicone tubing + fittings | 1 set | Local hardware store | ₹59 | ||
| Total | Total | ~₹2,400 | |||
Manufacturing Status
Updates
Prototype v3 passed field testing!
After 5 months of continuous operation in three test sites, Prototype v3 has exceeded all performance targets. Lab results confirm 99.97% bacteria removal and 99.9% virus inactivation. The bamboo housing showed zero degradation despite monsoon conditions. We are now finalizing the production BOM.
UV-C LED driver redesigned for reliability
We discovered thermal issues with the original LED driver during extended operation in direct sunlight. The redesigned board uses a more conservative derating curve and adds a thermistor-based cutoff. Updated KiCad files have been pushed to the repository.
Prototype v2 deployed for field testing
Three units deployed across rural sites near Mysore. Each unit is processing 100-140 liters per day for households of 5-8 people. Community health workers are logging daily output and collecting water samples for monthly lab analysis. Early feedback on usability has been very positive.
Discussion (4 comments)
As a public health researcher, I want to highlight how important the dual-barrier approach is in this design. Ceramic filters alone handle bacteria well, but they are unreliable against viruses. The UV-C stage is the right call. Have you considered adding a chlorine dosing option as a tertiary backup?
Thanks for the expert perspective! We considered chlorine dosing but decided against it for v1 because it adds supply chain complexity. For high-turbidity events, we recommend a pre-settlement step using alum. The modular design means a chlorine stage could be added later.
Shipping to Japan -- is that feasible with the battery included? LiFePO4 batteries have strict air freight regulations. I want to order the Workshop Pack but need to know about customs and shipping logistics.
Love the CERN-OHL-S licensing choice. I teach an appropriate technology course at TU Berlin and would like to use this project as a case study. The combination of open hardware, local manufacturability, and rigorous field testing makes it ideal.
Early Bird
₹1,500- 1 fully assembled unit
- Complete schematics and source files
- Name in project credits
Maker Bundle
₹3,500- 1 complete kit (unassembled) with all parts
- 3 extra filter elements
- Your name etched on the PCB silkscreen
- Printed assembly guide
Workshop Pack
₹12,000- 5 complete units (assembled)
- Workshop hosting guide and slides
- Priority email support from the maker
- Logo placement on project page
Backed the Maker Bundle tier. I run a small NGO in rural Maharashtra and we have been looking for exactly this kind of solution. The fact that the filters can be manufactured locally is a game changer for us. How difficult is the production process?
Great question! The filter production follows the Potters for Peace protocol, specifically designed to be teachable to local potters. A potter with basic experience can learn the process in about 2 days. We have a detailed training guide in the repository.