low power mode and temp variation
August 23, 2006 by Duncan | permalink
Set-up another 19 node network of Micaz motes with 6 mts310 sensor boards and 13 mts300 sensor boards. Running mts310CB code in low power mode. I initially sat all the motes together (image above) to see how close the various sensor readings were, a crude callibration test. The graph below shows that for the first 12 hour + period there was quite a variation on for example the temperature sensor - a variation of 1.5 degree C - more than i was expecting. I will log a call with xbow help desk.
The other reason for the experiement was to see how long the batteries last in low power mode... will post the results when I have them.
Comments
Case Reference #00002054
---------------------------------------------------------------
Type: Wireless Hardware
Sub Type: Sensor Boards
Case Reason: Calibration and Repair
Date Created: 8/23/2006
Last Updated: 8/23/2006
Subject:
---------------------------------------------------------------
callibrating temp sensors
Question:
---------------------------------------------------------------
I have a 19 node network running in the office using Micaz with mts300 and mts310 boards. At the start of the test I sat all the nodes together to see how the different sensor readings varied across motes. I was suprised to see a temp variation of 1.5 deg C - is this normal? I am running xmesh mts310CB in low power mode with reworked sensor boards. Images of the motes sitting together on my desk and the resulting screen shot in Moteworks for the 12 hour duration. http://blogs.driversofchange.com/emtech/
Response:
---------------------------------------------------------------
What you are seeing is normal. The low cost thermistors used on MTS300/310 are accurate only up to +/-3 C. The MoteView uses a generalized equation to convert the voltage output from the sensor into deg C. There is a variation from sensor to sensor and for more accurate values, user needs to individually calibrate the sensors (this could improve the accuracy to within 1 deg C).
Sincerely,
Giri Baleri
Crossbow Technology, Inc
www.xbow.com
Posted by: Dunc | August 24, 2006 09:35 AM