[Tinyos-help] TinyDB and MICAz

[Stefano Tennina]

Hello everyone,
On a Windows 2000 system I installed the TinyOS 1.1.11 distribution.

Without any modification in the codes, I experienced two strange problems 
running
TinyDB on MICAz.

When a query like this is running on MICAz nodes equipped with MTS310 sensor 
board:
SELECT nodeid, temp FROM sensors
SAMPLE PERIOD 2048

1. Temperature readings are unstable, that is they oscillate e.g. from 490 
to
520 (a range of more than 2°C (23,2°C - 25,6°C) based on the conversion 
formula
found in the sensor datasheet) !!

2. Readings come from sensors only for 23 epochs. After that, without any 
external
intervention, green leds of motes blink and no more data arrives. Moreover, 
if
I add the light field in that query (SELECT nodeid, temp, light ...), nodes
correctly don't stop themselves automatically.

Note that it's all ok if the query is SELECT nodeid, light ...

All this didn't happen with the old version of TinyDB 
(task-tinydb-1.1.1Nov2003)
on MICA2 nodes.

Can anyone tell me why this happens ??

PhD Stefano TENNINA
Dept. of Electrical Engineering and Centre of Excellence DEWS
University of L'Aquila
ITALY