It's possible that the FLASH store takes a long time,
I've never used it so I don't know. You might try flashing
LEDs at significant points in the process and measuring
the actual time with a scope.
I'm not clear why you start a new timer with 500 interval.
Assuming your messages are not throttled you should be able
to start sending a new one from the sendDone() of the old.
As I said, if you aggregate multiple samples into a single packet
(your slippery use of sample and packet is/was confusing) you should
be able to keep up with a 10/sec rate indefinitely.
MS
raghavendra a wrote:
Thanks for replying.
Yes I am using call Timer.start(TIMER_REPEAT, 100); for data acquisition.
I sample at 100ms until there are 1000 samples stored in the Flash
memory(I write an array of 250 samples four times). So this would take
around 100*1000*10^-3 which is equal to 100 secs or approx. 2 minutes.
After 1000 samples are written I stop the timer and call
Timer.start(TIMER_REPEAT, 500); and start reading out each of the
samples from the Flash and send each of them as a radio packet.(I have
No constraints on the Reading speed)
So I should start getting these messages after around 2mins, but i get
them after exactly 300-301 secs. Which boils down to 3 samples being
sampled instead of 10.(1000 samples collected in 300 secs means around 3
packets per second).
I am using Single hop.
Sincerely,
Ragh
On 10/16/07, *Michael Schippling* <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
I assume you have something like this driving your data acquisition:
call Timer.start (TIMER_REPEAT, 100);
so you (should) get about 10 sample cycles per second.
Are you then sending one sample per message, or aggregating them in
a manner like Oscilloscope? When you say "only 3 packets/sec is being
sampled" it sounds like you are not aggregating, and if not, how do
you know you're only getting 3 samples/sec?
And according to my, now old, measurements a mica2 system should be
able to send about 25 messages per second. Are you using a multi-hop
layout? You (should) be able to put up to 14 2-byte samples into the
29 byte message payload and at (lets be conservative, with no hops)
20 messages/sec, get 280 samples/sec.
MS
raghavendra a wrote:
> Hi,
>
> I am using MICA2 motes with MDA320 sensor boards. In my application I
> sample analog data at the rate of 10 samples/sec, store the values in
> the Flash, and then read them sequentially. I do the READ and
send the
> data back to the base at a slower rate since only 3packets/sec can be
> sent at the most. But I see that only 3packets/sec is being
sampled. How
> can I increase the sampling rate with MICA2 motes?
>
>
>
> Thanks,
> --
> Ragh
>
>
>
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Ragha
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