Concept of the dudhya project
v2.2.0.125

The dudhya project researches, and implements where possible, the resurrection of older smartphones: giving them a second life running an open-source operating system, so they can be repurposed as embedded systems and sources of sensor telemetry rather than discarded.

This document defines the project's goal, scope, and boundaries. It is a living document and will be updated as the project evolves. Decisions that shape the content of this document are recorded with rationale in ResearchJournal.org.

Older phones accumulate as people upgrade to newer ones, and each one is a small, self-contained computer with a battery, a radio, a screen, and a genuinely rich set of sensors — accelerometer, gyroscope, magnetometer, GPS, and more — discarded well before any of that hardware has actually failed. Resurrecting one gives it a real second purpose rather than letting it sit unused.

Run an older phone on an open-source operating system, preferably GNU/Linux, so it can be repurposed as an embedded system and a source of sensor telemetry.

Each real deliverable below addresses one concrete part of taking a phone from "discarded" to "usefully repurposed":

• Reviving the phone itself. Dudhya.org is the step-by-step procedure document: which devices are viable candidates, how to unlock, flash, and boot an open-source OS (postmarketOS) on each, and what was actually confirmed working (sensors, networking, GPS) versus still open, per device.
• Getting a usable, up-to-date install onto the device. dudhya-host-connect (run on a host machine) and dudhya-device-update (run on the device itself) bring a fresh install online and up to date, over either a direct USB cable or the device's own radio, without requiring a pre-existing network to already be configured.
• Making the device network-flexible once revived. dudhya-wifi-mode switches a device between acting as a normal WiFi client (station mode) and as its own access point (ap mode), so a repurposed device can either join an existing network or serve as one, depending on where it ends up deployed.
• Turning the phone into a source of sensor telemetry. dudhya-sensord reads the device's own real sensors and publishes the readings over MQTT, so a repurposed phone can act as a genuine embedded telemetry source rather than just an idle computer.
• Freeing the device from its own aging battery. A real, ERC-verified KiCad schematic and breadboard-style diagram (both generated by packpay, this project's own netlist-driven schematic and diagram engine, extracted into its own independent project) design the external, regulated power circuitry needed to run a candidate device without depending on its own battery, whose capacity only degrades with age. See Dudhya.org's own "Power management: running without a battery" section for the real design.

See the project's own README for how to build and use each of these, and Index for the full set of project documents.

The name is an abbreviation of the Sanskrit phrase: दूरतः ध्वनिः यन्त्रपुनरुत्थानम् (duratah dhvanih yantrapunrutthanam), approximately "sound from afar device resurrection" — fitting for a project about reviving phones as remote sensor devices. Incidentally, "dudhya" also means milk in some Indic languages, a coincidence rather than a deliberate reference.