RSSI info / provide signal strength

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data
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RSSI info / provide signal strength

#1 Post by data » 05 Jan 2017, 19:51

While on my search for the best receiver module for RFLink, I stumbled over the RXB6 Version 2!

Besides being a sensitive receiver anyway, its main advantage over any other receiver seems to be, that
it has an additional analog RSSI-signal output. Connecting this pin to an analog input of the Mega2560 will
enable you to get the signal strength of the received device!

See datasheet (PDF) at http://www.rficy.com/wp-content/uploads ... 2/CY07.pdf

I just ordered one, since it's really cheap - €1.21, free shipping: http://s.click.aliexpress.com/e/7Q3J2Nj

Anybody else thinks that this is a great feature?
Last edited by data on 05 Jan 2017, 21:21, edited 1 time in total.

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Stuntteam
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Re: RSSI info / provide signal strength

#2 Post by Stuntteam » 05 Jan 2017, 20:28

Sounds good..
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Justblair
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Re: RSSI info / provide signal strength

#3 Post by Justblair » 06 Jan 2017, 09:40

I have tried to find the RSSI. The datasheet does not really make it clear as to how you enable the "optional" RSSI

I tried opening the metal case up and connecting to one of the pins (I believe it is an analog signal). But I grew frustrated when I could not get any really sensible readings from it.

Tell us how you get on. I wanted to use this to create a very cheap rf location device for model rockets.

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Re: RSSI info / provide signal strength

#4 Post by Stuntteam » 06 Jan 2017, 11:04

RSSI (analog) signal should be on pin 6 (DER)

I guess the problem is how to trigger mode 3..
In normal operation pin 6 is a copy of pin 7
Then you can pull pin 6 high or low to affect the operation mode.
But how to get it in mode 3.. ?!
-=# RFLink Gateway Development Team #=-
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data
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Re: RSSI info / provide signal strength

#5 Post by data » 06 Jan 2017, 11:28

From what I understand, only v2.0 of this module provides RSSI out.
Maybe versions < 2.0 has some parts missing or a different pcb.

See e.g. http://www.jmrth.com/en/rxb6.asp
> ...
> Analog RSSI Output (only for V2.0)

Which version do you have? Can you post a photo? What is printed on the back of the pcb?

data
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Re: RSSI info / provide signal strength

#6 Post by data » 06 Jan 2017, 11:42

@justblair: Here's one for you: http://www.instructables.com/id/433-MHz ... /?ALLSTEPS

I just found something else: Apparently, the SYN470RF IC also offers RSSI on pin 13 (CAGC):
... voltages presented here [on PIN 13] ranged from ~1.34V (when beside a companion 433 MHz beacon transmitter) to ~2.54V no signal. ...
http://www.picaxeforum.co.uk/showthread ... -RSSI-hack

Update: Here's the SYN470 Datasheet: http://ex.kabobo.ru/tw_files2/urls_26/4 ... docs/2.pdf

Please add a small subroutine which measures the voltage on an analog input and (perhaps optionally - 10;RSSI=on; ) appends that value to the serial output.
Last edited by data on 06 Jan 2017, 11:47, edited 1 time in total.

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Re: RSSI info / provide signal strength

#7 Post by Stuntteam » 06 Jan 2017, 11:44

v2.0 would be the industrial version. The problem is not so much the version though..
But rather how you get the module into this 3rd operation mode so that the RSSI signal is supplied on the DER pin (pin 6).
I have not found any datasheet or info that shows what to do.
In default mode it just supplies data and is the same as pin 7. This to be pinout compatible with other modules.

Alternatively, we could check the SYN470R (315mhz)/SYN480R (433mhz)
It does only have pins for vcc/ground/data but on the chip itself, pin 7 is CACG which would be an RSSI signal..
This could be hooked to one of the analog pins of the Mega and we can have the rflink code read the value and forward the rssi.

Most of the SYN modules have the small 8 pin chip.. in that case pin 7 is CACG
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data
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Re: RSSI info / provide signal strength

#8 Post by data » 06 Jan 2017, 15:14

Here's something that might save you some time when implementing the RSSI output.
Despite being developed for the analog RSSI output of a RFM12B, it should be somewhat
similar to our modules:

https://hallard.me/rfm12b_arssi-library/

data
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Re: RSSI info / provide signal strength

#9 Post by data » 06 Jan 2017, 20:45

@Stuntteam:
And when you are at it, please also add some kind of heartbeat for the noisefloor:
a periodic (e.g. maybe 1 or 5 minutes interval?) reporting of the background noise.

That would be really great!

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Re: RSSI info / provide signal strength

#10 Post by Stuntteam » 07 Jan 2017, 00:51

uh.. not sure what you mean with that..
We already have a ping/pong mechanism that is used by Domoticz etc to check if RFLink is still functional..
-=# RFLink Gateway Development Team #=-
Introduction: http://www.nemcon.nl/blog2/
Generic Support forum: http://www.esp8266.nu/forum/viewforum.php?f=8

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