A Phenix device should be buildable from parts found everywhere, repairable with a soldering iron, and hold the whole library in a pocket. Everything is open: the plans, the code, the mistakes.
Everything below is at prototype stage. Nothing is for sale. The 3D renders of the devices are concepts; only the WiFi hotspot has already worked on a real phone.
The two devices
Phenix 001, the small one. A pocket reader, no bigger than a small remote control, holding the whole library on a memory card and showing it on a small, frugal screen. Common parts, a case you open with a screwdriver, a replaceable battery.
Phenix 002, the big one. A larger device, with a colour screen wide enough to read maps. Two memory card slots under a rubber flap: it can read a Phenix 001's card, check its library and repair damaged sheets. Modules plug onto pins: solar panel, dynamo, lamp. And a broken Phenix should be able to run again on a salvaged screen, even one from an old payment terminal.
What already exists: the Phenix hotspot
This is the first prototype that works. An electronic board costing a few euros opens a WiFi network called Phenix, with no password. Any phone that connects to it opens the whole library, without internet and without installing anything: the page opens by itself, like a hotel WiFi portal.
The parts
| Part | Role | Rough price |
|---|---|---|
| ESP32-C3 "Super Mini" | The brain and the WiFi | 3 to 5 € |
| USB-C cable | Power and programming | already at home |
| Power bank | Battery life | already at home |
| Micro SD card module (optional) | For a bigger library | 1 to 2 € |
Two versions
- Without an SD card: the full app, compressed (under one megabyte), is written straight into the board's memory. Nothing to solder. This is the version that worked.
- With an SD card: the library sits on a FAT32 micro SD card, prepared on the computer. Wiring: CS to GPIO7, MOSI to GPIO6, SCK to GPIO4, MISO to GPIO5, plus 3.3 V and ground.
Building it
- Install Arduino IDE 2, add Espressif's ESP32 boards, choose the ESP32C3 Dev Module board.
- In the Tools menu: Partition Scheme: Huge APP, and USB CDC On Boot: Enabled.
- Open the hotspot program, in the materiel/phenix-001-v0 folder of the repository, and upload.
- If the upload won't start: unplug, hold the BOOT button down, plug back in, release, try again.
- On the phone: WiFi settings, network Phenix. If the page doesn't open by itself, type 192.168.4.1 in the browser.
What was tried, and what we learned
The screen of an old Nokia phone: the idea was to reuse the colour screen of a dead phone. Two obstacles stopped it: a 24-pin connector with pins 0.4 mm apart, almost impossible to solder without fine equipment, and a backlight needing about 13 volts. Lesson: for a device everyone must be able to rebuild, a screen module sold for microcontrollers, already on its small board, beats an exotic salvaged part. See Screens.
Next planned: a 2.8-inch colour screen with a built-in SD card reader, or a 2.9-inch electronic ink screen, which keeps its page without power and reads in full sun, see The electronic ink screen.
The principles behind the design
- Parts found everywhere, online and in electronics shops, replaceable one by one.
- Everything is documented: schematics, code, parts list, in the public repository. A device whose insides nobody knows can't be repaired.
- The library stays readable without the device: they're the same text files as everywhere else. An SD card pulled from a broken Phenix reads on any computer.
- Energy first: a device that must last far from sockets picks its components for their consumption before their power.
The project as a whole is presented in The Phenix project.