Smart thermometer and hygrometer X-Sense STH51 — temperature and humidity monitor

X-Sense STH51 Smart Thermometer/Hygrometer is a compact device for continuous monitoring of temperature and relative humidity in homes, offices and specialized spaces such as terrariums, greenhouses and incubators. It provides precise local measurements, cloud data export and remote access via compatible apps, and integrates with Amazon Alexa for voice queries.

Advantages

The device uses a high-precision Swiss sensor that delivers temperature accuracy down to ±0.2°C in the main operating range and humidity accuracy as low as ±2% RH within 10–90% RH. It supports cloud data export for long-term analysis, offers instant push notifications when values cross set thresholds, and is powered by two replaceable AAA batteries for up to one year of operation. The compact ABS housing and simple mounting accessories allow flexible placement in small or confined spaces.

Suitable for

• Home and office indoor climate monitoring
• Terrariums and greenhouses
• Incubators and breeding environments
• Storage of humidity-sensitive items (e.g., cigars, instruments)

Key specifications

• Manufacturer: X-Sensor
• Model: STH51
• Power supply: 2 × AAA batteries (replaceable), 3 V DC
• Battery capacity: 1200 mAh; battery life: up to 1 year
• Material: ABS
• Operating temperature: -20 to 60°C (-4 to 140°F)
• Operating humidity: 0–100% RH
• Temperature accuracy: -20–0°C: ±0.2–0.4°C; 0–60°C: ±0.2°C
• Humidity accuracy: 10–90% RH: ±2% RH (maximum ±3.5%); 0–10% / 90–100% RH: ±2–3% RH (maximum ±3.5–5% RH)
• Indicators: Red/Blue light
• Alarm sound: no built-in sound; notifications via app and base station

How to use

Insert two AAA batteries, place the sensor at the monitoring location and follow the companion app instructions to add the STH51 to your account. Configure measurement intervals, threshold values and cloud export in the app. To use voice queries, link the device in the app to your Amazon Alexa account and enable the relevant skill. Position the sensor away from direct heat sources or water to ensure accurate readings.

Usage recommendations

For reliable long-term monitoring, place the device at representative height and location for the monitored environment, avoid direct sunlight and large airflow, and perform occasional battery checks. Use cloud export to keep historical records when tracking changes for plants, incubation or storage conditions.