Wireless sensor network - Smilenet

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Wireless sensor network

Contents 1 Method: 1.1 Summary: 1.2 Radio frequency used: 1.3 Radio protocol used: 1.4 Range/Power (line of sight/dBm): 1.5 Hop modes: 1.6 GPRS: 1.7 Mesh limitations: 2 Additional information: 2.1 Sensor compatibility: 2.2 Data reading frequency: 2.3 Storage of data/backup: 2.4 Power consumption: 2.5 Reliability: 2.6 Installation procedure: 2.7 Installation underground possible: 2.8 Battery life: 2.9 Battery type 2.10 Maintenance required /Ease of maintenance: 2.11 Support: 2.12 Software: 2.13 Cost (non profit): 3 What to watch out for: 4 Problems/Questions: 5 Links 6 References

[edit] Method:

[edit] Summary:

Smilenetz means Soil Moisture Intelligent Long-Range Environmental Network

[edit] Radio frequency used:

868 MHz and 2.4 GHz

[edit] Radio protocol used:

[edit] Range/Power (line of sight/dBm):

20 km line of sight

300 m wet forest

at 868 MHz with 300 mW and quarter wave antenna

[edit] Hop modes:

Point-to-multipoint or Zigbee dependent on radio module

[edit] GPRS:

GPRS modem at gateway

[edit] Mesh limitations:

[edit] Additional information:

[edit] Sensor compatibility:

1 Wire

Digital IO

8 channel 10 bit AD converter, 0 to 2.5V

Frequency counter

RS232

Future options: SDI12, I2C, SPI

[edit] Data reading frequency:

Adjustable, e.g. 30 s, 1 min, 15 min

[edit] Storage of data/backup:

SD card on node (e.g. 2 GByte)

CF card on Gateway (4 GByte)

Server with database on Internet

Data format: plain ASCII text file

Future option: database

[edit] Power consumption:

Sleep mode: about 40 uA

Active mode without radio/sensor: 8 mA

Active mode with soil moisture sensor: 50 mA for 400 ms

Active mode with radio RX: 50 mA

Active mode with high power radio TX: 150 mA

[edit] Reliability:

Years in service: 1 year

Failure rate instrument (years):

Packet failure (%): Depends on environment

[edit] Installation procedure:

Configuration in lab

Power on

Range test in field, handheld radio for communication

Monitoring software for incoming packets including RSSI

[edit] Installation underground possible:

yes

[edit] Battery life:

1 min interval: 2 weeks

90 min interval: approx. 2 years

[edit] Battery type

4x AA, 6V (5.2 V)

Sanyo Eneloop NiMh rechargeable, 2000 mAh, self discharge about 15% in 1 year

Alkalines as well (solar power optional in future)

[edit] Maintenance required /Ease of maintenance:

Change of battery required

[edit] Support:

Yes, but research institution

Software debug: Monitor mode to see all raw data, over the air programming in future

[edit] Software:

Web friendly interface:

Yes, Webpage with graphics based on Gnuplot

Data base:

No, future optional

Scripting language:

No, future optional

Update in the field:

Yes, but only with wired connection, wireless update is future option

Open source:

Yes (Linux, gnuplot, mysql)

[edit] Cost (non profit):

30 Euro microcontroller board

15 to 50 Euros radio (depending on frequency and power)

Gateway: 135 Euro embedded pc +30 to 65 Euro for radio modem

GPRS: 150 Euro

Communication costs: 0.2 Euro for 1 MByte

[edit] What to watch out for:

[edit] Problems/Questions:

[edit] Links

Projects that used the above equipment:

Other related web sites:

Technical information: http://www.mx.hs-mannheim.de

Distributors

[edit] References