Comprehensive inventory of all physical devices — processor, connectivity, power, and deployment details.
| Device |
Chipset |
Power |
Qty |
| Thermostat |
Nordic nRF5340 |
4× AA (~1 season) |
1 / radiator |
| Climate Sensor |
Nordic nRF52840 |
CR2450 (~2 years) |
0–1 / room |
| Central Unit |
RPi CM4 + nRF52840 |
Mains |
1 / home |
Example — 4-room apartment:
1 Central Unit + 4 Thermostats + 2 Climate Sensors = 7 devices.
Mounted on each radiator. Measures room temperature and humidity (Sensirion SHT40), runs PID control locally, and actuates the radiator valve via a stepper motor. Includes an LCD display showing current temperature and setpoint, plus physical buttons for manual adjustment. Supports on-device fire alarm detection via Edge AI (TFLite Micro).
| Parameter |
Value |
| Chipset |
Nordic nRF5340 — dual-core Cortex-M33 (App 128 MHz + Net 64 MHz) |
| Module |
BT40 (Fanstel) — pin-compatible, drop-in replaceable |
| Memory |
App: 1 MB Flash + 512 KB RAM · Net: 256 KB Flash + 64 KB RAM |
| Radio |
2.4 GHz — Matter-over-Thread, BLE 5.4 (commissioning) · Zigbee planned |
| Peripherals |
ADC, I²C, SPI, PWM, USB — motor control, LCD, buttons, SHT40 |
| Power |
4× AA batteries — ~1 heating season · mains adapter option for relay use-case |
| Deployment |
1 per radiator |
| Migration path |
nRF54L series (pin-compatible, improved power efficiency) |
Optional companion to the thermostat. Placed away from the radiator for a more representative room reading. Provides high-precision temperature and humidity data (Sensirion SHT40, ± 0.2 °C / ± 1.8 % RH). Designed for ultra-low power — runs on a single coin cell for approximately two years.
| Parameter |
Value |
| Chipset |
Nordic nRF52840 — Cortex-M4F @ 64 MHz with FPU |
| Memory |
1 MB Flash + 256 KB RAM |
| Radio |
2.4 GHz — Matter-over-Thread, BLE 5.0 (commissioning) · Zigbee planned |
| Sensor |
Sensirion SHT40 (I²C) — power-gated to minimize idle draw |
| Power |
CR2450 coin cell — ~2 years |
| Deployment |
0–1 per room (optional) |
| Migration path |
nRF54L15 (ready for quick migration) |
One per home. Acts as the gateway between the local Thread network and the cloud. Buffers telemetry, distributes OTA firmware updates to edge devices, and runs schedules. Includes a co-located nRF52840 radio for Thread Border Router functionality.
| Parameter |
Value |
| SoM |
Raspberry Pi CM4 — Broadcom BCM2711, quad-core Cortex-A72 @ 1.5 GHz |
| Memory |
1–8 GB LPDDR4, 8–32 GB eMMC (configurable) |
| Networking |
Wi-Fi 802.11ac (2.4/5 GHz), Bluetooth 5.0 |
| 802.15.4 radio |
Co-located nRF52840 via UART/SPI — Thread Border Router · Zigbee planned |
| OS |
Custom Yocto Linux image (Kirkstone) |
| Power |
Mains (USB-C / DC) — always-on, ~3 W idle |
| Deployment |
1 per home |
¶ Connectivity Standards
| Standard |
Status |
Used By |
Purpose |
| Matter |
✅ Current |
All edge devices |
Unified smart home interop (Apple · Google · Amazon) |
| Thread (802.15.4) |
✅ Current |
Thermostat, Climate Sensor, CU |
Low-power IPv6 mesh; self-healing topology |
| BLE 5.0 / 5.4 |
✅ Current |
All devices |
Matter device commissioning and onboarding |
| Wi-Fi 802.11ac |
✅ Current |
Central Unit |
Cloud link (HTTPS / REST), local app access |
| Zigbee |
🔮 Planned |
All edge devices |
Backward-compatible mesh networking |