This article lists the technical specifications of the Cobra Climate Sensor.
Connectivity
- Compatibility: open standard secure MQTT (SMQTT).
- Ports: secure MQTT on port 8883/TCP.
- WiFi: 2.4 GHz, 802.11 b/g/n (up to 150 Mbps); frequency range 2412–2484 MHz.
- IP address: one per sensor, DHCP preferred.
- Data usage: approx. 1–3 kB per sensor per hour; bandwidth below 1 kB/s.
Power
- USB powered, 5V (minimum 4.9V at the end of the cable).
- Energy use below 1 W, typically 600 mW.
Casing
- Unobtrusive, organic design.
- Colour: white (optionally available in RAL colours).
- Exterior: plastic, with an optional white-label / logo finish.
- Dimensions: 128 mm × 105 mm × 34 mm.
- Weight: approx. 110 grams.
Internal sensor modules
The sensor contains three components: a microcontroller (the "brain" that transmits data wirelessly), a dedicated CO₂ sensor, and a combined temperature, humidity and air-pressure sensor.
CO₂ — Telaire T6615 Dual Channel CO₂ Sensor Module
| Property | Value |
|---|---|
| Range | 0 to 50,000 ppm |
| Accuracy | 400–1000 ppm: ±75 ppm · >1000 ppm: ±10% |
| Temperature dependence | 0.2% FS per °C |
| Stability (over 10-year life) | < 5% of FS, or < 10% of reading annually |
| Pressure dependence | 0.135% of reading per mm Hg |
| Response time | < 2 minutes for a 90% step change (typical) |
| Warm-up time | < 2 minutes operational, 10 minutes full |
At device level, Cobra Climate specifies a typical CO₂ deviation of ±30 ppm.
Humidity & Temperature — Sensirion SHT40
| Property | Value |
|---|---|
| Typ. relative humidity accuracy | 1.8 %RH |
| Operating humidity range | 0–100 %RH |
| Humidity response time (τ63%) | 4 s |
| Calibration | Factory calibration |
| Typ. temperature accuracy | 0.2 °C |
| Operating temperature range | −40 to 125 °C |
| Temperature response time (τ63%) | 2 s |
| Supply voltage | 1.08–3.6 V |
| Average supply current | 0.4 µA |
Security
Sensor communication is one-way (the sensor publishes data; there is no inbound channel back to the device). The WiFi and MQTT broker passwords are stored encrypted, with the MAC address encrypted per sensor. Firmware updates currently require physical access to the device.