Hardware Update: New Multi-Sensor Board
We assembled and tested our latest sensor board which supports 7 different sensors.
The different sensors on the board are:
- TEPT5700: Ambient light Sensor (Analog)
- NXFT15XH103: Thermistor (Analog)
- LM75B: Temperature Sensor (I2C)
- CC2D33S: Relative Humidity and Temperature (I2C)
- MS5637: Barometer/Altimeter (I2C)
- LIS2DH12: Accelerometer (I2C)
- TSL45315CL: Ambient Light Sensor (I2C)
In addition there is a buffer IC (SN74LVC1G125DBVR) for interfacing with flow meters with pulse output.
The pics below show the sensor board mated to a WSN1101L wireless mesh node through two 2×7 connectors.
We have written drivers for each sensor on this board. All the digital sensors are accessed over a single I2C bus. We made sure there is no address conflict. Each sensor responds to a unique 7 bit address.
Each of these digital sensors has a sleep mode to conserve battery life. The analog sensors are connected to different 10 bit ADC channels on the WSN1101’s MSP430 micro-controller. Power to each analog sensor is gated by a MOSFET which can be switched off to cut off power to the corresponding sensor and associated signal conditioning circuit. Each MOSFET is controlled by a separate GPIO on the WSN1101’s MSP430 micro-controller.
The thermistor and the analog ambient light sensor can be mounted outside a weather proof enclosure while the rest of the node and battery etc can stay inside. These two sensors are connected to the sensor PCB through two terminal blocks.
A U.FL to SMA RF cable assembly is used to connect the WSN1101L’s radio board to an external bulk-head mounted antenna.
For more information, please visit http://www.wisense.in.