MCU-less experiments

Some days ago I was reminded of the fact that the Hall-effect sensor I’m currently testing, could very well do without a JeeNode; a combination of this sensor with a XBee could maybe suffice as a wireless sensor. Right; so I made this breadboard setup:

A3214 sensor with XBee

It looks like it’s working, although I haven’t spent that much time on this yet. Yes, I do see incoming “IO Data Sample” packets, I see differences in the bits for “open” and “closed”, but I also see multiple packets (3, 5) where 1 packet would be perfect.

Another big issue is that in this setup the XBee is working in “No Sleep” mode, and that’s a no-go of course when this is going to be battery-powered. Do I want to use cyclic sleep and have IO samples sent at a regular interval? No!, that’s always too late…

Does the XBee Digital IO Change Detection work while it’s asleep? Probably not, although I haven’t tested that yet. But the manual doesn’t give any clue that this will work, so chances are small that it will.

Maybe I can do something with the “Cyclic Sleep Pin-Wake” Sleep mode? Never used that one before…

Or, use a different approach; use “a” circuit, triggered by the sensor, that will wake up the XBee, make the XBee send a IO Data Sample (this can be done with some specific XBee settings) and put it back to sleep after the XBee has finished sending the sample. That’s where I have used a JeeNode for so far .. 🙂 ; but maybe there’s a simpler solution?

Time to find out!

Tagged , . Bookmark the permalink.

One Response to MCU-less experiments

  1. Pingback: Half-way there?

Leave a Reply

Your email address will not be published. Required fields are marked *