Monitoring sensors beyond Wi-Fi from a single panel

Cold room temperature, the boiler room, a warehouse door, a generator battery… A business's most critical points are often where Wi-Fi and cabling don't reach. Giving every point its own internet link is expensive and leaves dozens of independent devices to manage.

Off-the-shelf IoT kits are usually tied to one sensor type or one cloud vendor, and adding a sensor often means reprogramming the device.

• Read sensors at remote points without an internet connection
• Drive relays, pumps and lighting safely from the panel
• Add a sensor without removing or reflashing the device
• Get notified when a threshold is crossed, and react automatically if needed
• Manage several sites or customers separately on one platform

Every stage was tried on real hardware (ESP32-S3, an E22 LoRa module, a Raspberry Pi). Most problems that never show up on a desk surfaced there and fed back into the design:

• The never-seen device. A device with no sensors defined was never handed to the gateway and stayed "never seen". Devices now announce themselves with a signed message.
• Late first reading. Adding an hourly sensor meant the first value arrived an hour later. A one-off read is now triggered as soon as the config is applied, so the first value arrives in seconds.
• Low voltage readings. The raw ADC formula read about 20% low without calibration; readings now use the chip's own calibration data.
• Colliding radio traffic. Independent timers for several devices could collide on the half-duplex module; all radio transactions now go through one ordered queue.
• False "offline". A device with a failed sensor but working link looked offline; link and sensor health were separated.