[Tinyos-help] Fw: Re: Heeeeeeeelp Voltage Supervisor & LPL

Sat Apr 4 09:14:18 PDT 2009

there must be somebody knows, I've read about LPL many times but it did not answer my questions

Hi everybody 
I've used LPL interface. but there is a point I just need to be sure about if you please. 
with using 

Timer.startPeriodic(5000); 
LowPowerListening.setLocalSleepInterval(1000); 

I take sample of the voltage and compare it with a threshold value, if it exceed this threshold it will send a message and if it lower than this threshold it will send another different msg. 

my question: 
when the mote TX (send ) if the RF is sleeping, wil it wake up automatically. 

when the mote RX (Receive) and the RF is sleeping, it will not wake up automatically but it will wait for the sleeping period to finish and wake up for 1000 to see if there something in the air ! right ? 

2nd. thing 
Sorry for late because i was looking for the user guide 
the User guide for MSP430XX 
http://focus.ti.com/lit/ug/slau056g/slau056g.pdf 

described the SVS 

The supply voltage supervisor (SVS) is used to monitor the AVCC supply 
voltage or an external voltage. The SVS can be configured to set a flag or 
generate a POR reset when the supply voltage or external voltage drops below 
a user-selected threshold. 
The SVS features include: 
AVCC monitoring 
Selectable generation of POR 
Output of SVS comparator accessible by software 
Low-voltage condition latched and accessible by software 
14 selectable threshold levels 
External channel to monitor external voltage

SVS Operation 
The SVS detects if the AVCC voltage drops below a selectable level. It can be 
configured to provide a POR or set a flag, when a low-voltage condition occurs. 
The SVS is disabled after a POR to conserve current consumption

concerning my question about using an external DC voltage source and the mote stop responding if the voltage is lower than 2V.
can I configure this value in my mote to change the lower value ?

Thanks  & Have a Nice Day

Mohamed

--- On Tue, 3/31/09, Janos Sallai <sallai at isis.vanderbilt.edu> wrote:

From: Janos Sallai <sallai at isis.vanderbilt.edu>
Subject: Re: [Tinyos-help] Voltage Supervisor
To: "Mohamed H. Seddik" <mhsedek at yahoo.com>, "tinyos forum" <tinyos-help at millennium.berkeley.edu>
Date: Tuesday, March 31, 2009, 6:06 PM

The mote will not work if the voltage is that low. Notice, however,
that the voltage of the battery is not decreasing linearly with time
when the battery is discharging. ( See charts for low current draws at
http://www.powerstream.com/AA-tests.htm )

> the mote will work from 3.3 - 2 v and then will be shutdown, and can not use the
> rest 2 V ???
The unit of energy is not Volt. It's Watt. Trying to answer your
question: If the battery voltage drops below 2V, the mote can't use
the remaining battery power.

> Can I change this by using for example modifying voltage supervisor ? How can
> be done for IRIS mote?
What voltage supervisor are you referring to?

> I've tried to measure the drawn current using DC source and AVOmeter (the
> all devices DC source + mote + AVO are serial connection) but I could not
> get any result. the mote does not turn on ?
You must be doing something wrong. Search the list archive on how to
measure current draw.

Janos

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