XBee, PIR Motion detector questions

Forum and Topics about ZigBee devices.

Moderators: Digit, Willem4ever

Post Reply
Digit
Global Moderator
Global Moderator
Posts: 3388
Joined: Sat Mar 25, 2006 10:23 am
Location: Netherlands
Contact:

XBee, PIR Motion detector questions

Post by Digit »

I've got this Motion sensor connected to an XBee.

This XBee is plugged into a XBee Explorer Regulated.
This Explorer takes care of supplying the XBee the required 3.3V.
Current setup (XBee, Explorer, Motion sensor) uses 40 mA.

In my first setup i used 4 x AA batteries and a LM7805 voltage regulator to provide 5V to the motion sensor and Explorer.
However, after around 16 hours the output voltage of the 4 AA batteries started to reach 5.5V and i think the LM7805 becomes unstable at that point, cause i see the XBee sending motion events even when there's no motion. Now i know a LM7805 needs more then 5.5V...

My questions are:

- Is using a 9V battery a better idea? it has much less mAh (580 vs 2850) then AA which will decrease time to switch batteries.
- Wouldnt it be better to get rid of the Explorer regulated, which is only needed for the 5V > 3.3V voltage regulation. This will only add more loss, right?

So actually i would need a voltage regulator that can provide me both 5V and 3.3V with minimal losses.
How can i do that? What's the best way?

Elektro gurus, your advice please :-)
User avatar
RDNZL
Forum Moderator
Forum Moderator
Posts: 1008
Joined: Sun Sep 24, 2006 1:45 pm
Location: Dordrecht, The Netherlands
Contact:

XBee, PIR Motion detector questions

Post by RDNZL »

Cannot advice on the best regulator, but I think the 7805 series are not very efficient.
Can those Xbee modules be put into sleep mode too?
Thats also an important energy saver, look here for more info (for JeeNodes) not exactly matching your setup, but useful info I think.
http://talk.jeelabs.net/topic/32

Regards,
Ron.
Post-IT
Member
Member
Posts: 448
Joined: Sat Feb 28, 2009 12:01 am
Location: Netherlands (Rotterdam)

XBee, PIR Motion detector questions

Post by Post-IT »

Found this note while I was browsing for more ZigBee reading, might help you out. There are 2 modes: Sleep (Cyclic) and Hybernate.

http://sensor-networks.org/index.php?page=0820520514

And some more discussion on the Sleep mode here:
http://www.picaxeforum.co.uk/showthread.php?t=10500
and here:
http://www.digi.com/support/kbase/kbase ... jsp?kb=193

Hope this helps you in the right direction.

I've been thinking about buying the Zigbee PIR in the Alertme kit (priced at 25 GBP): http://www.alertme.com/smart-energy/sta ... n-the-box/
User avatar
Willem4ever
Global Moderator
Global Moderator
Posts: 805
Joined: Mon Oct 30, 2006 3:48 pm
Location: Uithoorn / Netherlands

XBee, PIR Motion detector questions

Post by Willem4ever »

Robert,

I think it would be better to design your solution with components which run on 3 Volt and not to use any voltage regulator at all. Once I have my setup running (on 3 volts) I'll post the results.
Post Reply

Return to “ZigBee Forum”