Author Topic: Synchronizing wireless data aquisition nodes  (Read 2101 times)

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Offline luky315Topic starter

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Synchronizing wireless data aquisition nodes
« on: February 02, 2016, 01:10:49 pm »
Is there a simple way for synchronizing a couple (4 to 12) wireless sensor nodes (max. 10m distance) to get a "simultaneous sampling" effect? The sampling rate is only 10sps, but the resulting jitter over time and temperature has to be better than 1µs.
I don't have other hard requirements and the nodes are line powered, so a low power wireless standard is not required.
Any suggestions?
 

Offline Neilm

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Re: Synchronizing wireless data aquisition nodes
« Reply #1 on: February 02, 2016, 07:12:05 pm »
A bit more information would be useful - is this just for triggering or would the results be read out over it? Are the sensor in line of sight to the receiver?
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Offline Kilrah

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Re: Synchronizing wireless data aquisition nodes
« Reply #2 on: February 02, 2016, 07:26:14 pm »
One of those extremely basic RF modules:
https://www.sparkfun.com/products/10534

There's zero processing on them, you're driving/getting stuff straight from the modulator/demodulator so no variable delays.
 

Online Jeroen3

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Re: Synchronizing wireless data aquisition nodes
« Reply #3 on: February 02, 2016, 07:34:41 pm »
Do you need instantaneous synchronisation or can it take a while?

This concept maybe?


Although 1 uS might be extremely difficult to achieve without external source (such as gps).
 

Offline C

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Re: Synchronizing wireless data aquisition nodes
« Reply #4 on: February 06, 2016, 07:50:33 pm »

You might look at loran-c

The master sends out a pulse.
The slaves receives the pulse and after a delay for each slave sends out a pulse.
master gets time for master sync pulse to time when master receives slave pulse, the time delay.
For what you want, delay has two parts.
1. Master to slave sync time
2. Slave sync time  to master.

For #1 you have master transmitter delay, air delay, slave receiver delay and delay to sync.
For #2 you have slave delay from sync, slave transmitter delay, air delay, master receiver delay.
Could help to change #2 by a fixed amount so the master has better data to work with for a correction message to slave.
 


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