Energy consumption optimization for a wireless sensor for the IOT

Energy consumption optimization for a wireless sensor for the IOT Francesco Orfei NiPS Lab, University of Perugia, Italy TSP S.r.l., Umbertide, IT francesco.orfei@nipslab.org

Outline Introduction to the aim of the project General description of the system General description of the electronics Design constraints of the autonomous wireless sensor node Design of the autonomous wireless sensor node 2

Introduction to the aim of the project Title: Research and development of a data logger for energy monitoring and energy efficiency augmentation of civil and industrial buildings. Proposer: BAS Engineering S.r.l. Partners: TSP S.r.l., NiPS Lab., Dept. of Electrical Engineering of the Univ. of Perugia 3

Introduction to the aim of the project Roles of the partners DB & CMS Electronics & Communication Data pre-processing TSP NiPS DEI 4

Outline Introduction to the aim of the project General description of the system General description of the electronics Design constraints of the autonomous wireless sensor node Design of the autonomous wireless sensor node 5

General description of the system WWW Building 1 Raw Data Raw Data Pre-processing Building 2 Building N Raw Data Pre-processed Data TSP NiPS DEI 6

General description of the system Data acquisition in each building Local data Data from other instrumentation (field bus) Router Internet To the pre-processor Remote data (wireless) 7

General description of the system R W W R C Router Data Collector W W W WSN B Field Bus C W W W B 8

General description of the system Local data (gateway) Data from instr. field bus WSN Backup battery status 3-phase voltages Rechargeable battery status Air temperature 3-phase currents Air temperature Air humidity 3-phase Air humidity Air pressure Phase to phase THD Air pressure Analog input 1 Phase to neutral THD Wall internal temperature Luminosity Frequency Luminosity Analog input 1, 2 3-phase active power Wall external temperature CO2 ppm 3-phase reactive power Digital input status 1, 2 Digital input status 1, 2 Fast counter input 1, 2 Water counter Gas counter 9

Outline Introduction to the aim of the project General description of the system General description of the electronics Design constraints of the autonomous wireless sensor node Design of the autonomous wireless sensor node 10

General description of the electronics RTX 2.4 GHz FSK Local data Gateway Isolated RS485 Dual core main controller Cortex A9 Linux Cortex M4 real time data acquisition Power conditioning Opto-isolated inputs RS232 Light sensor Isolated 5V power supply Humidity sensor Temperature sensor Pressure sensor External analog inputs 11

https://www.udoo.org General description of the electronics Main controller + gateway RS485/RS232/Wireless to Internet 1x ARM Cortex -A9 up to 1 GHz 1x ARM Cortex -M4 up to 200 MHz GPU 2D/3D Camera Interface NTSC/PAL analog video input interface 1GB RAM WI-FI BLUETOOTH 4.0 LOW ENERGY FAST ETHERNET 9-AXIS MOTION SENSORS 3x UART ports 2x CAN Bus interfaces Android Marshmallow 6.0.1 & Linux UDOObuntu2 (14.04 LTS) 12

General description of the electronics WSN Main controller + gateway RS485/RS232/Wireless to Internet WSN RF RTX Power Supply Cortex A9 TCP/IP Local sensors Cortex M4 WSN WSN AC network analyzer RS485 ModBus RTU Other instrum. 13

Outline Introduction to the aim of the project General description of the system General description of the electronics Design constraints of the autonomous wireless sensor node Design of the autonomous wireless sensor node 14

Design constraints of the autonomous WSN WIRELESS INEXPENSIVE AUTONOMOUS COMPACT WSN SEVERAL SENSORS EXPANDABLE WITH A DISPLAY EASY TO OPERATE 15

Design constraints of the autonomous WSN WIRELESS Radio link to the gateway up to 100 m AUTONOMOUS Battery powered, no charger or AC/DC power supply, expected sleep current 100 μa SEVERAL SENSORS Air temperature, humidity, pressure, light intensity, 2 remote temperature Sampling period 5 minutes WITH A DISPLAY Display for configuration and measurements 16

Design constraints of the autonomous WSN INEXPENSIVE Final cost 50 COMPACT Max size 10 x 10 x 4 cm EXPANDABLE Digital spare I/O for future use EASY TO OPERATE Simply place the battery, set a jumper and/or push a button, read information on the display 17

Outline Introduction to the aim of the project General description of the system General description of the electronics Design constraints of the autonomous wireless sensor node Design of the autonomous wireless sensor node 18

Design of the autonomous WSN Wireless link based on Nordic nrf24l01+ 2.4GHz ISM band GFSK RF Transceiver 250kbps, 1Mbps and 2Mbps on air data rates Ultra low power operation 11.3mA TX at 0dBm output power 13.5mA RX at 2Mbps air data rate 900nA in power down 26μA in standby (not used) 19

Design of the autonomous WSN Autonomous a single AA NiMH battery is requested a single solar cell is used to recharge the battery low power step-up voltage regulator: Microchip MCP16251 I OUT > 100 ma @ 3.3V V OUT, 1.2V V IN No load total input current: 17 μa @1.2 V IN Low Start-up Voltage: 0.82V, 1 ma load Low Operating Input Voltage: down to 0.35V Automatic PFM/PWM Operation 20

Design of the autonomous WSN Sensors disconnect Battery holder Step-up converter From the μc Battery isolator Radio disconnect 21

Design of the autonomous WSN 22

Design of the autonomous WSN ±0.3 Typical accuracies Power dissipation 23

Design of the autonomous WSN Typical active supply current @ 2.5 V: 40 μa @ 20 bit resolution < 10 ms 265 μa @ 24 bit resolution, up to 1 s 24

Design of the autonomous WSN Not enough!!! 25

Design of the autonomous WSN 26

Design of the autonomous WSN Current to Voltage converter VPP TEPT4400 To the 10 bit ADC of the μc 27

Design of the autonomous WSN Display LCD Lumex 3½ digit reflective + AY0438 display driver 28

Design of the autonomous WSN Driving the LCD.. μc 29

Design of the autonomous WSN µcontroller PIC24F16KA102 Sleep mode + Watchdog Timer 870 na @3.3V Up to 16 MIPS Operation @ 32 MHz 8 MHz Internal Oscillator with 4x PLL Option 17-Bit by 17-Bit Single-Cycle Hardware Multiplier 32-Bit by 16-Bit Hardware Divider To save data 30

83 mm Conclusions The WSN has been designed and realized according to the specifications The firmware is in beta testing preliminary results confirm the power consumption expectations optimization of the performance is still in progress 80 mm 31

Questions? Thank you! 32