Arduino Forum

Products => Arduino Yún => Topic started by: rtrelease on Sep 20, 2013, 12:28 am

Title: Mystery component on Yun board?
Post by: rtrelease on Sep 20, 2013, 12:28 am
Thanks! Just received my Yun from Adafruit and had great fun setting up the WiFi and loading my first sketches.  What a great way to make Arduino control and programming available over the Web and through a WiFi hotspot!

I asked about the following over at Adafruit Forum--they said they didn't know and the question might be asked here:

Say, what's that 'mystery component' on the front of the board, at the upper right corner of the MIPS shield? Looks kind of like a micro switch with the button missing--shown on the Arduino layouts and images on your (Adafruit) site and Arduino.cc, but not openly identified. Could it be something like an external antenna connector for the WiFi, or is that just wishful speculation?

Cheers!

['DB]
Title: Re: Mystery component on Yun board?
Post by: Federico_Vanzati on Sep 20, 2013, 12:53 am
you guessed right. It is an antenna connector to extend the WiFi range.
The form factor of this antenna connector is called "U.FL"
Title: Re: Mystery component on Yun board?
Post by: rtrelease on Sep 20, 2013, 02:21 am
Thanks!  Very cool.

['DB]
Title: Re: Mystery component on Yun board?
Post by: ah01 on Sep 27, 2013, 06:46 pm
Be careful. It looks like U.FL but it's NOT! Actually it's SWF connector (http://www.digikey.com/us/en/ph/Murata/SWF_Connector.html). Unfortunately purpose of this connector is mainly during product testing, so counterpart is far less available than U.FL connector.
Title: Re: Mystery component on Yun board?
Post by: Flyingbees on Sep 29, 2013, 11:31 am
Does it mean that the only way to extend wifi is through USB port ?
Title: Re: Mystery component on Yun board?
Post by: Clemens on Nov 05, 2013, 08:33 pm
An other mysterious formation is the four slight diagonal THT holes for header pins on the Wifi side and the six on the Ethernet plug. No labeling, any idea?
Title: Re: Mystery component on Yun board?
Post by: bjarne on Nov 06, 2013, 02:13 am
Those holes are for mounting a PoE module.
Title: Re: Mystery component on Yun board?
Post by: federicofissore on Nov 16, 2013, 11:27 am
I've just received an answer from the hardware guy: the connector is a MM8430-2610 (see this (http://www.murata.com/products/catalog/pdf/o33e.pdf)). You can plug in a MXGS83RK3000/MM126036: once plugged in, the switch connector will turn the internal antenna off and use the probe as an external antenna
Title: Re: Mystery component on Yun board?
Post by: awardblvr on Feb 03, 2014, 08:58 pm
Here's an article on how these work:

http://www.murata.com/articles/ta0791.pdf (http://www.murata.com/articles/ta0791.pdf)

These are for test...Not intended to be used as a permanent connector for range extension. You may get lucky. It is rated at 100 cycles max.  (Remember they probably used a number of these cycles during manufacturing.)

Summary. It is a Microwave Switch Connector.   No observable "lip" on connector to hold a connection permanently.  It is a N/C connector and passes the signal through to the on-board antenna.  When interrupted by the male pin, inserted during test, it re-routes the signal to the contacting pin, disconnecting the on-board antenna. 

Digikey has these connectors: http://www.digikey.com/us/en/ph/Murata/SWF_Connector.html (http://www.digikey.com/us/en/ph/Murata/SWF_Connector.html) But the official male connector is not a latching type, like the U.FL types.  The one male plug available is http://www.digikey.com/product-search/en?site=us;lang=en;vendor=490;Keywords=MXHS83QE3000 (http://www.digikey.com/product-search/en?site=us;lang=en;vendor=490;Keywords=MXHS83QE3000) but is ~US$50 and doesn't appear to have a holding "lip".

They are completely incompatible with the U.FL type.... No amount of forcing, twisting or whining is going to get these to mate.

It COULD BE that someone clever could replace that SMT connector with a pinout-compatible U.FL type, (voiding any warranty, and possibly messing things up,) but some hacker might get lucky and post the results here.  We are probably all anxious to be able to find a way to have the Yún in a metal enclosure and yet still have WiFi connectivity.
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on Feb 07, 2014, 05:01 pm
The reason external antenna is needed is:



Friis Transmission Formula with Propagation Law

(http://s21.postimg.org/bjuhudv3b/Friis.gif)



if in urban environments;-




in line of sight environments;-



http://forum.arduino.cc/index.php?topic=175577.msg1304059#msg1304059 (http://forum.arduino.cc/index.php?topic=175577.msg1304059#msg1304059)








Title: Re: Mystery component on Yun board?
Post by: sonnyyu on Feb 07, 2014, 05:42 pm
An other reason is reduce interference.

The Omni type  antenna ( build in chip antenna)  has 360 degree field pattern

The pattern below is from a Yagi antenna : From this you can see the Yagi can block all other router signal outside from 60~120 degree.

(http://s27.postimg.org/cb2gwqw0j/yagi.jpg)
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on Feb 07, 2014, 06:11 pm
More Information about transmit power:

Maximum Transmit Output Power in the ISM bands.

(http://s23.postimg.org/y108l43ln/fcc.gif)

http://wisp-router.com/page.php?11 (http://wisp-router.com/page.php?11)

The part 15 of the FCC rules. (http://www.ecfr.gov/cgi-bin/text-idx?tpl=/ecfrbrowse/Title47/47cfr15_main_02.tpl)

Title: Re: Mystery component on Yun board?
Post by: mortonc on May 11, 2014, 04:25 pm
Did you ever find a solution for an antenna?
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 12, 2014, 02:05 pm
Any high gain 2.4 Ghz antenna will work.








Title: Re: Mystery component on Yun board?
Post by: mortonc on May 12, 2014, 03:59 pm

Any high gain 2.4 Ghz antenna will work.


  • Pach Panel Antenna

  • Dish Antenna

  • Dipole Antenna

  • Yagi Antenna

  • Grid Parabolic Antenna




What about people saying that it woud for after a number of cycles? Would it be a feasible long term solution?

Thanks




Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 12, 2014, 08:29 pm

...
What about people saying that it woud for after a number of cycles?
...


What do you mean?
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 16, 2014, 03:15 am
The connector is designed for semi permanent application. It mean once connect it and leave it.
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 30, 2014, 01:46 am

...
Friis Transmission Formula with Propagation Law

(http://s21.postimg.org/bjuhudv3b/Friis.gif)


  • R = Maximum range for communication link

  • N = Propagation Law (N=2 for line-of-sight, N=4 for urban environments)

  • PT= Transmit power

  • GT= Total antenna gain

  • ? = Wavelength

  • PR= Receiver sensitivity

  • FM= Fading margin


...


To complete Friis Transmission Formula;-



Above is for FYI only.
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on Jun 11, 2014, 07:52 pm
FYI;-

People make 2 Openwrt base AR9331 with high gain antenna nodes on 1 mile distance  wells communications.

Just Give Me Antenna and I'll Show You the World!


Title: Re: Mystery component on Yun board?
Post by: sonnyyu on Jan 20, 2015, 01:55 am
Dragino (Yun compatible) MS14 has Antenna plug

http://wiki.dragino.com/index.php?title=MS14_Antenna (http://wiki.dragino.com/index.php?title=MS14_Antenna)



16 dbi Antenna

(http://i.imgur.com/ZpHfegq.png)


Title: Re: Mystery component on Yun board?
Post by: pete_dl on May 02, 2015, 07:22 pm
I have managed to successfully attach an external antenna to the Yun, but it is a hack.

I had misread this thread, bought a "SMA Female Plug to IPX U.FL Female Pigtail Cable" ( http://www.ebay.co.uk/itm/231098912466) , connected it to the Yun and saw no improvement.

Under a microscope, I could see that both the socket and plug were female. (see attached photos).

As I had nothing to lose, I thought I would have a go at creating a pin that would bridge the two female connectors. 1/0.6mm solid core wire fitted snugly in both connectors. I guessed at the correct length. Luckily i seemed to judge it about right and the plug is held firmly on the socket.

Amazingly, it worked. The Yun seems to auto sense the stronger signal. With no antenna connected to the SMA connector, the signal strength was about 35%. With the antenna connected, it bumped up to about 80%. I plugged/unplugged it a handful of times to convince myself it was working.

Obviously, with no soldering, this is might not be the most reliable of connections.

I would be interested to know from an RF expert whether I have managed to fluke a solution or whether the RF signal can jump the gap of a "not great" connection.

Let me know if you can reproduce my results.

Pete.

Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 08, 2015, 04:44 pm
Custom made connector:

(http://i.imgur.com/pZAEiKY.jpg)

original murata connector, price not working( $80) and height is not. I got customer engineer drawing done. but  MOQ is too high. plus Intellectual property?

(http://i.imgur.com/ABc7QOy.jpg)


Case to hold custom made connector.








Title: Re: Mystery component on Yun board?
Post by: ShapeShifter on May 08, 2015, 07:25 pm
Custom made connector:
Wow. Interesting solution, but it costs more than the Yun! No wonder you didn't go into production.

It's a bit of a hack, but I think Pete's solution is much more practical.

I would be interested to know from an RF expert whether I have managed to fluke a solution or whether the RF signal can jump the gap of a "not great" connection.
I'm not an RF engineer (as far as I'm concerned, RF is black magic!) but while I'm sure that the "not great gap" is introducing some reflections that may affect signal quality, it's hard to argue with the success you're reporting.

Does anybody know if there's a way for the Yun to report signal quality (or signal/noise ratio) in addition to signal strength?
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 08, 2015, 07:47 pm
Wow. Interesting solution, but it costs more than the Yun! No wonder you didn't go into production.
...
$80 is murata price, I got quota about few $ for 10K MOQ. I don't need 10K for my single Yun.  :smiley-money:  Plus It might be  murata  Intellectual property?





Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 08, 2015, 08:05 pm
...
Does anybody know if there's a way for the Yun to report signal quality (or signal/noise ratio) in addition to signal strength?
Code: [Select]
iw dev wlan0 survey dump
Survey data from wlan0
        frequency:                      2412 MHz
        noise:                          -95 dBm
        channel active time:            105 ms
        channel busy time:              36 ms
        channel receive time:           35 ms
        channel transmit time:          0 ms
...






Title: Re: Mystery component on Yun board?
Post by: ShapeShifter on May 08, 2015, 11:53 pm
Code: [Select]
        noise:                          -95 dBm
Thanks! This would be the interesting number to see with Pete's "imaginative" adapter. But of course, to really know if it's significant, it would need to be compared to the noise figure for a a "proper" adapter...

Still, it would be interesting to see Pete's noise figure with and without the external antenna.
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 12, 2015, 06:40 pm
(http://i.imgur.com/zqKyLGm.png)

They are completely incompatible with the U.FL type.... No amount of forcing, twisting or whining is going to get these to mate.

http://forum.arduino.cc/index.php?topic=188976.msg1574902#msg1574902 (http://forum.arduino.cc/index.php?topic=188976.msg1574902#msg1574902)

The top connector inside have to build in with forcing to connect well  & cut off build in antenna.



Title: Re: Mystery component on Yun board?
Post by: Bournetoride on May 12, 2015, 07:10 pm
I have replaced the original outlet with one that will mate with any ordinary antenna lead.
I have mounted my Yun + sensor shield in an old wireless router case, using the antenna giving me good house wide connection
I am not an R.F. engineer but can solder with a magnifying loupe to my eye, requires a steady hand
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on May 12, 2015, 08:11 pm
(http://i.imgur.com/SF2wcDb.jpg)

Those connector works fine with following limitations:

Title: Re: Mystery component on Yun board?
Post by: thataintworking on Jun 01, 2015, 07:00 pm
Here's an article on how these work:

http://www.murata.com/articles/ta0791.pdf (http://www.murata.com/articles/ta0791.pdf)

These are for test...Not intended to be used as a permanent connector for range extension. You may get lucky. It is rated at 100 cycles max.  (Remember they probably used a number of these cycles during manufacturing.)

What does "rated at 100 cycles max" mean? 
Title: Re: Mystery component on Yun board?
Post by: ShapeShifter on Jun 01, 2015, 07:05 pm
What does "rated at 100 cycles max" mean?  
In this case, a cycle is a single instance of mating and disconnecting the connector. This connector is rated for 100 such cycles, after which the manufacturer does not claim that it will still make connections properly. In other words, it is a low duty cycle connector that is not designed for frequent connections/disconnections. If you are going to use it, plan on leaving the antenna connected and don't mess with it a lot.
Title: Re: Mystery component on Yun board?
Post by: acastronovo on Jun 04, 2015, 06:01 pm
It seems the 100 cycles refers to how many times you can physically plug and unplug this connector...if you get the adapter cable you will see that it snaps on with gentle pressure...so my guess is that if you continued to physically plug and unplug this connection...more than 100 times...eventually it would wear out. But as for function, it works well for me, and gave me significant signal boost- wifi signal from 150" away.

here are the parts I used:

http://www.adafruit.com/products/945

http://www.digikey.com/product-detail/en/132171RP/ACX1247-ND/1011924

http://www.digikey.com/product-search/en?site=us;lang=en;vendor=490;Keywords=MXHS83QE3000
Title: Re: Mystery component on Yun board?
Post by: sonnyyu on Jun 04, 2015, 06:17 pm
It seems the 100 cycles refers to how many times you can physically plug and unplug this connector...if you get the adapter cable you will see that it snaps on with gentle pressure...so my guess is that if you continued to physically plug and unplug this connection...more than 100 times...eventually it would wear out. ...
You guess is correct. the other side adapter cable will last thousands times more than this connector.

This connector is design for RF calibration purpose only, more  less few times use, but adapter cable is design for RF calibration thousands  RF circuit boards.






Title: Re: Mystery component on Yun board?
Post by: Quantumn on Apr 08, 2019, 07:10 pm
I have managed to successfully attach an external antenna to the Yun, but it is a hack.

I had misread this thread, bought a "SMA Female Plug to IPX U.FL Female Pigtail Cable" ( http://www.ebay.co.uk/itm/231098912466) , connected it to the Yun and saw no improvement.

Under a microscope, I could see that both the socket and plug were female. (see attached photos).

As I had nothing to lose, I thought I would have a go at creating a pin that would bridge the two female connectors. 1/0.6mm solid core wire fitted snugly in both connectors. I guessed at the correct length. Luckily i seemed to judge it about right and the plug is held firmly on the socket.

Amazingly, it worked. The Yun seems to auto sense the stronger signal. With no antenna connected to the SMA connector, the signal strength was about 35%. With the antenna connected, it bumped up to about 80%. I plugged/unplugged it a handful of times to convince myself it was working.

Obviously, with no soldering, this is might not be the most reliable of connections.

I would be interested to know from an RF expert whether I have managed to fluke a solution or whether the RF signal can jump the gap of a "not great" connection.

Let me know if you can reproduce my results.

Pete.
I know microwave Pete.  There is no 'jumping a gap' with microwave.  You'd need a plasma for that.  In fact as frequencies get higher and higher signal begins to travel only on the outside surface of the conductor to a greater and greater degree.

You've succeeded with your novel pin and I'm about to do the same thing, because my fingers are literally 50x the size of these connectors, otherwise I'd solder in a U.Fl male.  I have access to a PCB microscope at the NW Maker Lab, but my fingers are too big (since I'm old) and I'm not so steady anymore.

One thing to be aware of is, assuming you'd used copper wire, it will oxidize;  this means the outer surface.  Notice all other components are gold-plated.  You have to make this connection gas-tight to prevent this.  I'll use silicone grease ("dielectric grease", auto parts store) to fill my connection.  I always inject it into RJ45's when I'm making up cables, whether they'll go outdoors or not.  I'll do my best to file the ends of the pin flat.

Then I'll hot-glue the wire to the board to reduce strain on the connectors, since this is going in my Tesla. I've rooted it and the Yun will give me remote access to the (hacked) car.