I just received my Bluetooth Low Energy SensorTag from TI and wanted to share my experience with it. Overall it looks like a great sensing device coming at an amazing price (25$ – free shipping- probably it is more of a promotion than an actual product).
SensorTag features 6 sensors in total (temperature, humidity, pressure, accelerometer, gyroscope and magnetometer) and it comes with a single cell coin cell battery (CR2032). Specs mention a quiescent current consumption of 8uA, allowing years of battery life!
The device itself is quite small allowing it to be carried in your pocket.
Setting it up and pairing it with an iPhone device is easy and straightforward.
TI provides a free iOS app (TI BLE Sensor Tag) which visualizes on your phone all the sensor information polled form the device. However connecting some times (or most of the times actually) requires that the device is waken from the sleep mode by clicking on the side button. I find this pretty annoying since you cannot rely on polling data from the device at long intervals (longer than its ‘active connection’ period is set to), but that’s probably a general issue with most Bluetooth devices. On the good side, once you click the wake-up button on SensorTag, the app finds the SensorTag and connects to it right away.
Here are some screenshots form the TI app:
An interesting (free) 3rd-party app that utilizes the TI SensorTag is ‘Comfort Guide – SENSiBLE’ by Sensirion AG (btw SenorTag is based on Sensirion SHT21 humidity sensor), that combines humidity and temperature data illustrating environmental conditions to the user in an understandable manner:
Wonder how you can write your own iOS app to read sensor data? No problem, the TI app includes also its own code as a sample of how to connect with SensorTag and read data from the available sensors (this one goes beyond open source, it’s integrated open source, or embedded open source!!):