MaBell Bluetooth Gateway: Project Plan on Deevnet IoTaaS

MaBell Project Plan v0: Foundation

Mon, 01 Jan 0001 00:00:00 +0000

MaBell Project Plan v0: Foundation #

Plan: MaBell Bluetooth Gateway: Project Plan · Next: v1: On the bench

✓ 23 | ↻ 0 | ⏳ 0 (23 total)

Legend: ✅ Complete | 🔄 In Progress | ⏳ Planned

Requirements, design and the first firmware: the base every prototype builds on. The firmware came first so the prototypes have something to talk to the hardware. Status: done, 2026-10-10.

Done when:

Requirements, constraints and acceptance criteria are written, with a risk register.
The system, power, audio and firmware design is finished, with a verification plan mapping requirements to tests.
The firmware builds and runs on the ESP32: Bluetooth HFP, the call state machine, tone generation, NVS configuration and logging.
MaBell is a Deevnet tenant: its state over MQTT, its events in the central log store, and a Grafana dashboard.

Not in v0: any hardware beyond the ESP32 itself (v1 onward); firmware release tagging (v1).

MaBell Project Plan v1: On the Bench

Mon, 01 Jan 0001 00:00:00 +0000

MaBell Project Plan v1: On the Bench #

Plan: MaBell Bluetooth Gateway: Project Plan · Previous: v0: Foundation · Next: v2: A low-voltage phone

✓ 0 | ↻ 0 | ⏳ 24 (24 total)

Legend: ✅ Complete | 🔄 In Progress | ⏳ Planned

The gateway works on the bench with stand-ins: a Bluetooth call runs end to end through a speaker and microphone, dialed with a bare rotary dial or DTMF from a phone app, and rung with an LED and an electronic ring. Status: current, the MVP.

MaBell Project Plan v2: A Low-Voltage Phone

Mon, 01 Jan 0001 00:00:00 +0000

MaBell Project Plan v2: A Low-Voltage Phone #

Plan: MaBell Bluetooth Gateway: Project Plan · Previous: v1: On the bench · Next: v3: Line voltage and a real bell

A real telephone makes and receives calls through the gateway, on a 5V DC loop with no high-voltage hardware. Status: next. Its definition of done and tasks are written when it becomes current, with what v1 taught.

📄 Build guide: notebook/build-guides/low-voltage-test-rig.md

Scope #

A cheap corded phone with a tone/pulse switch replaces v1’s stand-ins:

MaBell Project Plan v3: Line Voltage and a Real Bell

Mon, 01 Jan 0001 00:00:00 +0000

MaBell Project Plan v3: Line Voltage and a Real Bell #

Plan: MaBell Bluetooth Gateway: Project Plan · Previous: v2: A low-voltage phone · Next: v4: Boxed and installed

A vintage rotary phone rings and works at line voltage, and the circuit board’s line interface is chosen. Status: planned. Its definition of done and tasks are written when it becomes current.

📄 Build guide: notebook/build-guides/slic-module-build-guide.md

Scope #

A SLIC (subscriber line interface circuit) gives the phone a real ~48V battery feed, 600Ω line and ringing voltage. The AG1171/KS0835F module does this from one 3.3–5V supply; the phone side goes on screw terminals or a protoboard, since tip and ring carry ringing voltage.

MaBell Project Plan v4: Boxed and Installed

Mon, 01 Jan 0001 00:00:00 +0000

MaBell Project Plan v4: Boxed and Installed #

Plan: MaBell Bluetooth Gateway: Project Plan · Previous: v3: Line voltage and a real bell

The end state: the gateway on its own circuit board, in an enclosure, installed at home and in daily use. Status: planned. Its definition of done and tasks are written when it becomes current.

Scope #

Circuit board: schematic capture and layout in KiCad, built around the line interface chosen in v3, with test points and a programming header.
Revisions: fabricate, assemble and bring up Rev A; fix what it shows in Rev B and later, until a board is electrically verified against the requirements.
Firmware: retuned for the board, with the full set of functional sections passing again.
Enclosure: designed (3D printed or fabricated), with connector placement, strain relief, and thermal and safety review.
Installed: wired to the house phone and in daily use, with a long-run stability check.
Documentation: the build, wiring, user and troubleshooting guides, and design notes and lessons learned.

Not in v4: building more units; MaBell is built once.