Thanks to TI, I received the new SensorTag v2 to play with a couple of days back. I’ll be putting out a few blog posts on the SensorTag2, the one below being a basic introduction and then hopefully try to set it up. Some of the screenshots below are taken from TI’s SensorTag landing page.
Below are some useful links before you start exploring the tag. The inlay pamphlet that comes in the box is not very useful.
Comparing the SensorTag2 with it’s predecessor
I prefer the newer version of the tag as it sits almost square , is more aesthetically pleasing as well as sheds a few millimeters in thickness. The older version is based on CC2541, which supports Bluetooth Smart only, whereas the new version is based on the CC2650, which supports Bluetooth, 6LoWPAN and ZigBee depending on the software stack used. The CC2650 consists of a Cortex-M0 RF core and a Cortex-M3 user application core. The V2 version of the tag has 10 sensors in total.
- TMP007 Infrared and Ambient Temperature Sensor.
- OPT3001 Ambient Light Sensor.
- HDC1000 Humidity Sensor.
- Bosch BMP280 Barometric Pressure Sensor.
- InvenSense MPU-9250 Accelerometer, Gyroscope and Compass.
- Meder MK24 Magnet Sensor.
The silicone rubber casing seems a bit smoother on the new tag. Not a big deal, just something I noticed.
Sensortag2 Block Diagram
Part Labels With The Casing On
- The power button can be accessed on the left side of the tag with the two window slits facing towards you. I definitely like the button on the previous version of the tag as it gave you a audible feedback with a “click-click”. It is kind of hard to make sure the button is pressed on the new one. The LED does help if the firmware uses it. The button has multiple profiles as shown in the image below.
- There are two slits in the silicone casing that act as windows for the following sensors:
- Ambient light
- The slits also act as a retainer for slipping in a strap for mounting purposes.
- The button on the right is similar in feel to the left one. The demo firmware allows it to cycle between different modes.
- A red/green LED is viewable through one of the window slits.
- The key chain access hole is retained, although it is entirely made of silicone and is a part of the casing. My only fear is the tag slipping out of the casing if used on a key chain. The older revision had the mount as part of the plastic body itself.
Inside The Casing -Top Side
On removing the silicone casing, the tag is projected by a hard plastic casing. It can be removed by pulling out the top tab slightly first and then sliding the plastic case out. The CC2650 sits on top surrounded by an InvenSense MPU-9250 9 axis and the other sensors, except the Microphone and Magnet sensor. Note that although the following is a rendering, mine shipped with version 1.2 too.
Inside The Casing – Bottom Side
The bottom side has the Magnet and Microphone sensors. The buzzer is on the top left. One fact to keep in mind is that if you are running the demo software, the buzzer is turned off to conserve battery. The battery is a 3.0V CR2032 coin cell. There is also support to hook up two AA bateries to power the SensorTag externally. The Knowles SPH0641LU microphone sensor talks via Pulse Data Modulation(PDM) to the CC2650.
The JTAG is a 10 pin connector that allows the SensorTag to connect to the debug DevPack for programming. A SKIN or expansion connector allows for serial communications( UART, AUDIO, SPI & I2C ) to pass through different Devpacks totalling 20 pins.
Applications are provided for both iOS as well as Android. They are pretty self explanatory, so I’ll not dive into it.
SensorTag2 Android Source Code.
The new SensorTag is definitely well made and comes with almost all the sensors you could dream off. The tag is definitely going to be popular especially in the IoT realm. I’ll try to cover the software environment in the next installment. You can subscribe in the box below to receive new updates.