Wi-Fi & Wireless Temperature Data Loggers

Three wireless technologies are common in temperature monitoring, and they solve different problems. Wi-Fi loggers join the site network and stream every reading to the cloud, so alerts arrive within minutes. Bluetooth loggers talk to a nearby phone and are used to collect data on demand, not to raise live alarms. Cellular (4G) loggers carry their own SIM and need no site network at all.

This page covers Wi-Fi and Bluetooth. If the site has no Wi-Fi, patchy coverage, or an IT team that will not allow devices on the network, a 4G M2M logger with a built-in SIM is usually the better choice; see the 4G M2M / GSM temperature data loggers.

All Ideabytes Wi-Fi loggers use 802.11 b/g/n at 2.4 GHz and run on a 5V/1A DC supply with an internal Li-ion battery that keeps them logging through a power cut. The single and dual-channel models have a 1.3-inch OLED display, a 4400 mAh battery with up to 20 hours of back-up, and 90 days of internal storage at a 15-minute interval, so readings taken during a Wi-Fi outage are not lost.

Where relative humidity matters as much as temperature, the Wi-Fi temperature and humidity loggers measure both and alert on either. The WTH120 takes an external probe for -40 °C to +120 °C and 0 to 100% RH (condensing) with ±2% RH accuracy, suited to cold rooms and harsh spaces. The WTH50 has a built-in sensor for 0 °C to +50 °C and 0 to 100% RH at ±2% RH, the simplest option for pharmacies, stores and offices. The WTH70 covers -20 °C to +70 °C and 0 to 99% RH (non-condensing) at ±3% RH.

For projects that need other inputs on the same device, the Wi-Fi customised room parameter data logging and live alerting system (WC-X) is configured with the sensors and accessories the site requires.

The BTH70 Bluetooth temperature and humidity data logger is for places where there is no network and no live alarm is needed, such as shipments, stores visited on a round, or equipment you check periodically. It measures -20 °C to +70 °C and 5 to 95% RH with ±3% RH accuracy, records every minute by default (configurable) and stores 32,000 records.

Data is downloaded to a phone over Bluetooth, with a range of up to 300 metres in long-range mode, and PDF reports are generated in the mobile app, which is available on Android. The logger is started from a button or the app, is IP65 rated, runs on a replaceable CR2450 coin cell and can be reused by reconfiguring it in the app.

Wi-Fi loggers send data to Ideabytes web and mobile apps (iOS and Android) at a default interval of 15 minutes, which you can change. Live alerts and app push notifications tell staff when a reading leaves its limits, SMS alerts are available, and every excursion is recorded in an alarm log and can be closed with a CAPA entry.

Reports are 21 CFR Part 11 compliant PDFs with an audit trail, trend graphs and mean kinetic temperature, generated on demand or on a schedule. On the 4 and 8-channel models, CSV reports can also be downloaded directly from the logger over Wi-Fi or with a USB cable. Software features are provided in different plans.

Before you order Wi-Fi loggers, confirm three things with your IT or facilities team. First, a 2.4 GHz Wi-Fi network (802.11 b/g/n) must reach every mounting point; 5 GHz-only networks are not supported. Second, the logger needs internet access to reach the cloud platform. Third, each logger needs a 5V/1A power point nearby, since the battery is for back-up during power failures.

If signal at the probe location is weak, mount the logger where coverage is good and run the external probe cable into the fridge, freezer or cold room; cable length can be customised. Where these conditions cannot be met, choose 4G or Ethernet.

Ideabytes IoT manufactures its loggers in India, is registered on GeM for government procurement and is a QCI-approved OEM. The Wi-Fi temperature loggers carry HSN code 90251990 and the temperature and humidity models 90258090. NABL-traceable calibration certificates are available on request. Probes for the external-sensor models are ordered separately.