description - farsens · hygro-fenix-h221 datasheet - ds-hygro-fenix-h221-v02 - may 2016 word...

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HYGRO-FENIX-H221

Datasheet

EPC C1G2 COMPLIANT BATTERYLESS RELATIVE HUMIDITY AND TEMPERATURESENSOR

Check for samples: HYGRO-FENIX-H221

FEATURES

• 860MHz-960MHz operation

• EPC Class-1 Generation-2 compliant

• ISO 18000-6 Type C compliant

• 96-bit EPC & 32-bit TID

• Humidity range: 0 to 100 %

• Humidity accuracy: ±4.5% rH (from 20% to80% rH)

• Humidity resolution: 0.004% rH

• Temperature range: -30◦C to +85◦C

• Temperature accuracy: ±0.5◦C (from 15◦C to40◦C)

• Temperature resolution: 0.016◦C

DESCRIPTIONHYGRO-FENIX-H221 is an EPC Class-1Generation-2 (C1G2) RFID tag based on Farsens’batteryless sensor technology. Built in a compact PCBformat, the tag includes a HTS221 relative humidityand temperature sensor from ST Microelectronics witha relative humidity range from 0% to 100% rH and atemperature range from -40◦C to +120◦C.

These RFID sensor tags are compatible withcommercial UHF RFID readers (EPC C1G2). Witha 2W ERP setup the battery-less temperature andhumidity sensor can communicate to over one meterand a half - 5 feet.

The HYGRO-FENIX-H221 is available in a variety ofantenna design and sizes, depending on the specificapplication. It can be encapsulated in an IP67 or IP68casing for usage in harsh environments.

BLOCK DIAGRAMThe HYGRO-FENIX-H221 tag consists of anANDY100 IC for energy harvesting and wirelesscommunication, a start-up circuitry based on avoltage monitor and a HTS221 relative humidity andtemperature sensor.

ANDY100D

RF+

RF-

CAL[2]

EERST

CS

SC

K

MIS

O

MO

SI

CAL[1]

CAL[0]

VD

D

2V

5

1V

8

1V

2

GN

D

VIO

VoltageMonitor

PG

VDD

GND

VDDTAG VDDSENS

GNDSENS

GNDTAG

C1

HTS221

SPC

CS

VDD

GND

SDI/SDO

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HYGRO-FENIX-H221

Datasheet - DS-HYGRO-FENIX-H221-V02 - MAY 2016 WWW.FARSENS.COM

D1

ANDY100D

RF+

RF-

VIOVDD

CAL[0]

GND

EERST CSSCKMOSIMISO

CAL[1]

CAL[2]

HTS221

CS

SD

I /

SD

OS

PC

VDDTAG VDDSENS

GNDSENS

GNDTAG

C1

VoltageMonitor

PG

1.8V 2.4V

SP

I/I2

C

RF

Fro

nte

nd

EPC C1G2 / ISO18000-6Cprocessor

SPI masterEEPROM

Power Supply Management

Clock oscillator

VDD

GND

VDD

GND

Co

ntr

ol l

og

ic

AD

C

MU

X

Clock and timing

Voltage and current bias

Sensor driver

Temperature sensor

Sensingelement

h

OpAmp

ChargeOpAmp

The ANDY100 IC includes a RF frontend for UHF RFID power harvesting and communication, a power supplymodule to generate the required voltage levels, a EPC C1G2/ISO18000-6C digital processor including a trimmedclock oscillator, a non volatile memory and a SPI master module. The SPI master module can be controlled viaEPC C1G2 standard memory access commands.

In order to isolate the supply of the RFID tag from the supply of the rest of the system, the diode D1 is included.The capacitor C1 acts as an energy storage unit to support current peaks of the system during active operation,such as initialization and measurement.

A voltage monitor is included to connect the sensor system only after the energy storage capacitor has beencharged. The voltage monitor connects the sensor system when the voltage in the capacitor is over 2.4V anddisconnects the sensor system when the voltage falls below 1.8V. This architecture avoids oscillation of thesystem during initialization.

The sensor included in this tag is the HTS221, which contains all the subsystems required to capture relativehumidity and temperature data. The humidity sensing element consists of a polymer dielectric planar capacitorstructure capable of detecting relative humidity variations. The measurement chain includes a low-noise capacitiveamplifier, which converts the capacitive imbalance of the humidity sensor into an analog voltage signal. Theoutput of the humidity and temperature sensors is multiplexed to an operational amplifier, and the data is digitizedwith the integrated ADC. A digital control logic is included for averaging filter to remove the high frequencycomponent. Finally, the data is made accessible through a SPI/I2C compatible interface.

In order to initialize the sensor, the RFID reader has to execute several write commands directed to the SPImemory space. Once the sensor has been configured in the desired operation mode, humidity and temperaturedata can be extracted executing read commands oriented to the proper addresses of the SPI memory space.

2 Copyright c©, Farsens


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Datasheet - DS-HYGRO-FENIX-H221-V02 - MAY 2016

CHARACTERISTICS

SYMBOL PARAMETER MIN TYP MAX UNIT

RFID

RFSENS RF sensitivity fully passive -4 -2 0 dBm

OPERATING CONDITIONS

TOP_TOP Operating temperature range -30 85 ◦C

TOP_ACC Full accuracy temperature range 0 80 ◦C

HUMIDITY SENSOR

Hrange Humidity range 0 100 % rH

Hacc Humidity accuracy

20% to 80% ±4.5 % rH

0% to 100% ±6 % rH

Hres Humidity resolution 0.004 % rH

Hnoise Humidity noise RMS 0.03 % rH

Hstep Humidity response time (t@63%) 1 10 s

TEMPERATURE SENSOR

Trange Temperature range -30 85 ◦C

Tacc Temperature accuracy ◦C

15 ◦C to 40 ◦C ±0.5 ◦C

0 ◦C to 60 ◦C ±1 ◦C

Tres Temperature resolution 0.016 ◦C

Tnoise Temperature noise RMS 0.007 ◦C

Tstep Temperature response time (t@63%) 1 15 s


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OPERATION

EPC reading

In order to read the EPC of the tag, commercial EPC C1G2 readers can be used. However, some considerationshave to be taken into account.

As the tag has a significant supply capacitor connected to VDD, the power-up of the system will be slow. It canlast several seconds. In order to speed up the charge process, the reader shall be configured to send poweras continuously as possible. Refer to the application note External capacitor on VDD of ANDY100 for detailedinstructions on how to set up the reader for best performance.

Once the supply capacitor is charged, the tag will respond with its EPC. From this point on, memory accesscommands can be used to control additional functionalities via the SPI bridge.

Calibration constants reading

Read constants (I) Operation: ReadMemory bank: User MemoryWord Pointer: 0x30Word Count: 6

The answer from the tag to such a request will contain 12 bytes of data. The EPC word size is 16bits and theSPI word size is 8bits. The answer received from the SPI interface is right aligned in the EPC words. Assumingthat the reader returns the received data in the buffer of bytes rawdata, the content of the answer is defined asfollows:

Byte 0

0x00 H0_RH 0x00 H1_RH

Byte 1 Byte 2 Byte 3rawdata

content

Byte 4

0x00 T0_C 0x00 T1_C

Byte 5 Byte 6 Byte 7 Byte 8

0x00 RES 0x00 T1/T0

Byte 9 Byte 10 Byte 11

// Get calibration constants (Part 1)

ushort H0_RH = data[1];

ushort H1_RH = data[3];

ushort T0_C = (((data[11] & 0x03) << 8) | data[5]);

ushort T1_C = (((data[11] & 0x0c) << 6) | data[7]);

Read constants (II) Operation: ReadMemory bank: User MemoryWord Pointer: 0x36Word Count: 2



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Byte 0

0x00H0T0

OUT_L0x00

H0T0OUT_H


content


H0_T0_OUT = (short)((data[3] << 8) | data[1]);

Read constants (III) Operation: ReadMemory bank: User MemoryWord Pointer: 0x3AWord Count: 6

Byte 0

0x00H1T0

OUT_L0x00

H1T0 OUT_H


content

Byte 4

0x00T0

OUT_L0x00

T0OUT_H

Byte 5 Byte 6 Byte 7 Byte 8

0x00T1

OUT_L0x00

T1OUT_H

Byte 9 Byte 10 Byte 11


H1_T0_OUT = (short)((data[3] << 8) | data[1]);

T0_OUT = (short)((data[7] << 8) | data[5]);

T1_OUT = (short)((data[11] << 8) | data[9]);

HTS221 initialization

In order to switch the sensor on, it is necessary to write a valid power mode. This configuration has to be doneat least once after the tag has been switched on. If the supply voltage suffers a voltage drop, the sensor will bereset. Thus, it is recommended to reconfigure these registers periodically or when all zero values are returned.

Write Power Mode Operation: WriteMemory bank: User MemoryWord Pointer: 0x20Value: 0x82 (recommended, refer to datasheet of HTS221 for customization)

Once the sensor is initialized, the humidity and temperature data can be obtained reading the correspondingregisters.

Humidity reading

Read Humidity Operation: ReadMemory bank: User MemoryWord Pointer: 0x28


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Word Count: 2

The answer from the tag to such a request will contain 4 bytes of data. The EPC word size is 16bits and the SPIword size is 8bits. The answer received from the SPI interface is right aligned in the EPC words. Assuming thatthe reader returns the received data in the buffer of bytes rawdata, the content of the answer is defined as follows:

Byte 0

0x00 HUM_L 0x00 HUM_H


content

In order to convert the ADC reading of the humidity sensor into actual humidity data, the calibration constantshave to be read first. This values can be read during the initialization of the tag, and shall be stored in the readerside. Once the calibration constants are known, just the humidity reading is required to refresh the sensed data.

// Get humidity value from sensor

Int16 rawHum = (Int16)(rawdata[3] << 8 | rawdata[1]);

// Operate actual humidity

Float Hum = (float)(H0_RH + (H1_RH - H0_RH)*(rawHum - H0_T0_OUT)/

(2.0*(H1_T0_OUT - H0_T0_OUT)));

Temperature reading

Read Temperature Operation: ReadMemory bank: User MemoryWord Pointer: 0x2AWord Count: 2

The answer from the tag to such a request will contain 4 bytes of data. The EPC word size is 16bits and the SPIword size is 8bits. The answer received from the SPI interface is right aligned in the EPC words. Assuming thatthe reader returns the received data in the buffer of bytes rawdata, the content of the answer is defined as follows:

Byte 0

0x00 TMP_L 0x00 TMP_H


content

In order to convert the ADC reading of the temperature sensor into actual temperature data, the calibrationconstants have to be read first. This values can be read during the initialization of the tag, and shall be stored in



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HYGRO-FENIX-H221


the reader side. Once the calibration constants are known, just the temperature reading is required to refresh thesensed data.

// Get temperature value from sensor

Int16 rawTemp = (short)(rawdata[3] << 8 | rawdata[1]);

// Operate actual temperature

Float temp = (float)(T0_C + (T1_C - T0_C)*(rawTemp - T0_OUT)/(8.0*(T1_OUT - T0_OUT)));


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HYGRO-FENIX-H221


DEMO SOFTWAREDemonstration software to read and control the HYGRO-FENIX-H221 is available in the web. Download the latestsoftware and user guide at: http://www.farsens.com/software.php. Currently, the software is compatiblewith the following UHF RFID readers:

Fixed readers

• Alien ALR9900

• AMS Radon

• Caen Muon DevKit - RS232

• CSL CS203

• Impinj R420

• Thingmagic M6

• Thingmagic M6e DevKit6

• Motorola FX9500

• Motorola FX7400/FX7500

• Nordic ID Sampo

• Nordic ID Stix

• RF-Embedded PUR500U

• Sirit IN610

Handheld readers

• Nordic ID Merlin

• Nordic ID Morphic

• Motorola MC9090G

• Motorola MC9190Z



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REFERENCESThe next table shows the available references of the HYGRO-FENIX-H221.

Ref. Name Description

34302 HYGRO-FENIX-H221-MKSWB HYGRO-FENIX-H221, meander wideband antenna, PCB format

For custom references with other antennas and housings, please contact us at [email protected].


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HYGRO-FENIX-H221


MECHANICAL DIMENSIONSAll dimensions are in millimeters.

MKS

Valid for reference(s): 34302

COHygro0Fenix

COLOGO

Maximum height: 3mm



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description - farsens · hygro-fenix-h221 datasheet - ds-hygro-fenix-h221-v02 - may 2016 word...

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