SparkFun Forums

[donaldhwong]

Hi Valen,

When I hooked up the Coordinator to the Moteino, there is the received packet that posted previously. However the RSSI reading was ZERO.

When I hooked the Router to the Moteino, there is nothing arriving through the RX.

Hope it helps.

Thank you.
Donald

[Valen]

Ok, the config settings of the router says it makes an analog measurement of pin AD2 every 100 ms and sends this as a broadcast, which ends up at the coordinator proven by the API packet. So there is RF traffic and there should be an RSSI pulse sequence generated. Atleast until 4 seconds has passed since the last packet.

The best would be to look at that RSSI/P0 pin voltage with an oscilloscope or logic analyser. But you probably don't have the latter, and I'm sure you would have considered an oscilloscope yourself if you had the chance. Maybe you have a multimeter (with/) or pulse frequency meter. Then you could tell that there is indeed a square/rectangular pulse coming out, or only a flatline high or low voltage.

Alternatively this forum thread on the Arduino site suggests that this 200 value in the pulsein command is too short. Which makes sense actually. Timeout at the 100% dutycycle is borderline. I don't know what kind of RSSI pulselengths or dBm values are to be expected though.

http://forum.arduino.cc/index.php?topic=205254.0

[donaldhwong]

Hi Valen,

I thought that you were busy.

Thank you for getting back to me so quickly. I measured the RSSI pin of Xbee with a multi-meter, the only instrument that I have right now. When the RSSI LED is lit, the voltage rises to 3.3. When the RSSI LED is dim, the voltage drops back down to zero.

I increase the duration to 1000, still says ZERO. What can I do? I know we are getting close.

Thank you,
Donald

[Valen]

Well, I wrote the earlier message in the morning. Now it is well into the evening here.

I'm sorry, but I'm running out of ideas. Try setting the parameter LOW to HIGH. If you have proved that the RSSI signal changes pulselength (dimming led) then I don't understand why the pulseIn function doesn't work. The only thing that could be is left is a bug in the Moteino code or something wrong with the libraries for it in the Arduino IDE. I'm totally unfamiliar with it.

[donaldhwong]

Dearest Valen,

Please don't apologize. I can not accept it. You don't know how much that you have taught me, guide me and gave me hope. Without you, I probably may have already gave up.

The funny thing is, I was just about to post to you the following:

Accidentally, I discover the RP setting on the Coordinator was set to ZERO. After I change it to default value of 28. I am readying the RSSI now.

Thank you and please enjoy my respect to you for your kindness and good heart.

Donald - a meditation teacher.

[Valen]

Ah, I see. Good thing it is solved now.

[stevech]

Hi Steve,

Thank you for your input. I purchased S2, because the sample URL uses S2. This is my first venture into Xbee. You think I should return the S2 and change it with S1?

Does S1 also have a RSSI output pin? I looked and can not find it.

I have downloaded the Xbee library, but no need to use it yet. Can you give me one, regarding RSSI?

the PWM RSSI, when integrated and fed to an LED or volt meter, shows rough RSSI.
The RSSI in dBm is within API messages.

The XBee S1 is much better for hobby use as you are not stuck with the complexities of Zigbee which is a tangent to a dark hole.

[donaldhwong]

Thank you Steve,

My RSSI test for Xbee ranges 61 to 103 with 86 average at 3 feet. 79 to 296 with average of 112 at 5 feet.

While RFM69W RSSI is much more stable. 34 to 28 with 31 average at 3 feet. 50 to 41 with average 46 at 5 feet.

Though, I don't know whether 433 MHz is less susceptable to interference than 2.4 GHz or not. If you have any experience, please share with me.

For my project, I decided to use RFM69W at the present time.

I must thank Valen and Steve for your guidance and support. I have learned at lot.

For someone missing the fun of digital electronics for over 30 years. It is most enjoyable.

Donald

[waltr]

Thank you Steve,

My RSSI test for Xbee ranges 61 to 103 with 86 average at 3 feet. 79 to 296 with average of 112 at 5 feet.

While RFM69W RSSI is much more stable. 34 to 28 with 31 average at 3 feet. 50 to 41 with average 46 at 5 feet.

Though, I don't know whether 433 MHz is less susceptable to interference than 2.4 GHz or not. If you have any experience, please share with me.

Donald

That sounds like multi-pathing is the cause of the variable RSSI readings.
Read up on this to understand why the reads vary. I'll also bet that even at fixed distances if you move the RSSI readings will change.

[jysgymg]

Hi, to whoever is till following this thread. I am having some trouble reading the RSSI values. I followed the profiles and codes but somehow my serial console only print out "Serial 1 not available".

Is there anyone here that can guide me? Any help would be appreciated!!

Thanks in advance!

[Valen]

Please start your own thread where you state your own problem in detail. Hijacking another's thread will only cause confusion because of mixed up information. Please provide your own information there. That means the code you used, schematic of how you have it connected. Modelnumbers of the parts in it. Uploaded settings files. And photo's of the breadboard or pcb if soldered to look for obvious wiring faults.

Since there is no mention of the text "Serial 1 not available" in the code of the very first link posted in this thread (the letsmakerobots.com site) I have no idea what could cause that or what you did. If you used some specific code then please direct us to it.

[jysgymg]

Sorry Valen, I am quite new to this forum. Basically, I followed donaldhwong's code and xCTU profiles that he uploaded. But yes, you are right, I will start my own thread.

Thanks!
J.Y.

P.S. Some forums require the users to write a certain number of posts before opening a thread. >.<

[stevech]

XBee Series 1 is much simpler to deal with, presuming you don't want/need Zigbee mesh routing.

Series 1 has the same sort of RSSI output pin: It's PWM. Some people wire this to LED(s) to have intensity = RSSI visually, or...
As you've found, the XBee Binary API can be used to get the RSSI of the last-received packet.

XBees uses IEEE 802.15.4 for the protocol and transmission modes. In the 2.4GHz Xbee S1, a good RSSI is -80dBm. At 1m range you'll see about -30dBm. At -90dBm and less, the frame error rate increases. IEEE 802.15.4 has an option (normally you enable it using XCTU) to use ACKs for every frame, and automatic retransmissions.

[jysgymg]

Hi Stevech, thanks for your reply. I will post a new thread about my problem with more details and hopefully you and Valen could guide me through over there. Just a quick summary, since this is an industrial scale project and not much of a hobby, which is the main reason that I pick xBee Series 2 instead of xBee Series 1 and I hope that using xBee Series 2 will be able to incorporate more complex programming from Arduino.

[Valen]

The Series 2 models do not leverage the amount of programming you can do with the Arduino. (It doesn't make the Arduino smarter or more capable) In fact the mesh routing requires more complex code to keep track of where packets are going and if they arrive. Also the notion that series 1 or 802.15.4 models are mere hobby-stuff as opposed to professional products is a false one. They have different features that should match your project requirements.