Wireless sensor network - Smilenet
Wireless sensor network
Method:
Summary:
Smilenetz means Soil Moisture Intelligent Long-Range Environmental Network
Radio frequency used:
868 MHz and 2.4 GHz
Radio protocol used:
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
Hop modes:
Point-to-multipoint or Zigbee dependent on radio module
GPRS:
GPRS modem at gateway
Mesh limitations:
Additional information:
Sensor compatibility:
1 Wire
Digital IO
8 channel 10 bit AD converter, 0 to 2.5V
Frequency counter
RS232
Future options: SDI12, I2C, SPI
Data reading frequency:
Adjustable, e.g. 30 s, 1 min, 15 min
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
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
Reliability:
Years in service: 1 year
Failure rate instrument (years):
Packet failure (%): Depends on environment
Installation procedure:
Configuration in lab
Power on
Range test in field, handheld radio for communication
Monitoring software for incoming packets including RSSI
Installation underground possible:
yes
Battery life:
1 min interval: 2 weeks
90 min interval: approx. 2 years
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)
Maintenance required /Ease of maintenance:
Change of battery required
Support:
Yes, but research institution
Software debug: Monitor mode to see all raw data, over the air programming in future
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)
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
What to watch out for:
Problems/Questions:
Links
Projects that used the above equipment:
Other related web sites:
Technical information: http://www.mx.hs-mannheim.de
Distributors