positioning of new USB port: Wireless antenna on PCB?

[jkn]

Hi All

I'm finally getting around to a project I've been meaning to do for a while ... fitting a second (...third...) USB port to one of my Jogglers.

I've got some USB sockets and have been hacking my case a bit, using information given in a couple of places, both on this site and elsewhere:

http://www.jogglerwiki.com/wiki/Additional_USB_Ports

http://www.justblair.co.uk/extending-th ... ities.html

I was about to start checking that things will fit, soldering up some wires etc. when I took a closer look at the Joggler's PCB. I have been planning to fit the 2nd USB port at the 'top left' side, ie. above the first one. This corresponds to the lower left side of the PCB as shown in the image below:

http://www.jogglerwiki.com/wiki/File:Co ... _usb_2.jpg

You see that long straight bit of copper tracking, going vertically 'up' from the bottom left corner? Just on top of that.

I've just realised that this looks awfully like an 802.11 wireless antenna tracked onto the PCB. If so, then I have a major concern about mounting a metallic USB connector pretty much directly on top of it (with a thin bit of double-sided adhesive tape, hot glue, or thin sliver of FR4 PCB material).

I will probably try to fit the connector nevertheless, but I wonder if anyone has been down this path and can offer any advice. Is this part of the PCB actually part of the wireless circuitry? Is this likely to make any difference to the reception? Any suggestions?

Thanks a lot.

Jon N

[pete]

Personally (note this is my opinion); no.

I have now "wired" most of my Jogglers (maybe 8 of them) with an internal USB port (wires though not physical ports).

I have gone to using very thin 24-26 guage wire passing them on the other side of the motherboard opposite of what is depicted in the wiki picture.

I have the two types of OpenPeak utilized WLAN USB cards. One has the two little antennas and the other has the antenna integrated into the USB stick itself.

To make "more" room in the case; one of my experiments was to remove the USB "socket" and solder on the 4 "extra" USB wires directly to the WLAN board. I then also added directly to the internal USB port a USB SSD card. I piggybacked the two boards together on the left hand side space. It worked but after a few days of running 24/7 the boards got a bit warm and that actually caused the WLAN card to drop its wireless connections.

You could too try purchasing a pair of wireless antennas for a netbook and wire them around the circumference of the case. This would give you the benefit of a better internally mounted wireless antenna.

Another experiment that is working is to trim the little plastic ridges there on the left side and behind the wlan card off.
Then I utilize this space for a ZIF SSD card with a long flat and folded ZIF cable to the PATA port. A second thing too I am doing is putting both the ZIF SSD card, ZIF cable folded over itself and a ZIF to USB board insulated and piggybacked together. This has been also working just fine 24/7 and not getting hot. Trimming way the extra plastic allows for the extra space.

My most current "experiment" has been relating to passing the very the 4 very thin USB wires out an existing little vent hole and attaching a USB device outside the back on the top and using the little vent holes to fix the device to the back of the joggler with small screws. I am doing this by taking apart the USB device and drilling two small holes in the case such that the screws going right into the back vent holes (very short little screws); then putting back together the USB device. I now have 6 Jogglers set up this way running 24/7 with no problems. This and using the internal USB port allows me to have an extra side port for just maintance stuff if I need to plug a keyboard in.

Personally in conclusion and relating to RF itself I would recommend an external to the case antenna and or device for wireless access as historically I have had many issues with the internally mounted wireless device. I have seen the same issue with my Chumby's and wireless digital picture frames.

I use mine with PnP3, SB Player, XBMC and propietary home automation touch screens. Much of the status's and communications of the propietary touch screens is layered with multiple screens each with upto maybe 50-100 variables that get constantly updated such that an intermittent loss of communications screws with my status screens.

[jkn]

Hi Pete, thanks for your reply

Personally (note this is my opinion); no.

Just to be clear - no as in, mounting a USB connector in that place will not compromise wireless reception?

I have now "wired" most of my Jogglers (maybe 8 of them) with an internal USB port (wires though not physical ports).

I have gone to using very thin 24-26 guage wire passing them on the other side of the motherboard opposite of what is depicted in the wiki picture.

Thin wires for power as well?

I have the two types of OpenPeak utilized WLAN USB cards. One has the two little antennas and the other has the antenna integrated into the USB stick itself.

[snip stuff re. addition of internal USB SSD]

You could too try purchasing a pair of wireless antennas for a netbook and wire them around the circumference of the case. This would give you the benefit of a better internally mounted wireless antenna.

Are there mini-sockets for two antennae on the WLAN board? will have to check...

[snip stuff re. ZIF/PATA]
Yes, your work in this area looks very interesting ... I have been half-following it with interest and this is another hack I fancy doing.

My most current "experiment" has been relating to passing the very the 4 very thin USB wires out an existing little vent hole and attaching a USB device outside the back on the top and using the little vent holes to fix the device to the back of the joggler with small screws. I am doing this by taking apart the USB device and drilling two small holes in the case such that the screws going right into the back vent holes (very short little screws); then putting back together the USB device. I now have 6 Jogglers set up this way running 24/7 with no problems. This and using the internal USB port allows me to have an extra side port for just maintance stuff if I need to plug a keyboard in.

This sounds like a good plan for a third USB port, which is something I also plan to do... FWIW I use an external USB DAC and would probably wire it externally this way. What do you mean by a 'USB device' BTW? A connector of some sort, or an actual dedicated device (such as a DAC)? Also, which USB traces on the PCB have you found best for this device?

Personally in conclusion and relating to RF itself I would recommend an external to the case antenna and or device for wireless access as historically I have had many issues with the internally mounted wireless device. I have seen the same issue with my Chumby's and wireless digital picture frames.

I seem to have relatively little 802.11 problems with my Jogglers, but it may be worth trying something like you suggest. I do get occasional radio drop-outs but I don't know if that is the wireless or my ADSL feed.

[...]

Thanks a lot for your thoughts.

Cheers
Jon N

[pete]

Just to be clear - no as in, mounting a USB connector in that place will not compromise wireless reception?

It could. The antenna at the end of the wire though is just got a little sticky tape holding it in place. You can move it a cm or two to the right and stick it there instead. There is some play in the cable.

I just cut out the USB port itself to make for more room and soldered the 4 USB wires directly to the board; then wrapped the board up some.

Thin wires for power as well?

Yes. The four wires are the same gauge. I also tried to use the standard USB colors of Red, Black, green and white. Initially I utilized 22 guage stranded alarm wire. It was too thick. You have to run it to the side of the motherboard. Actually the thickness of the wire does cause a distoration of the LCD backlighting when the case is closed on the Joggler. I stripped out the wire from an older USB cable and it was 24 or 26 guage; almost thick hair like guage size. It is a bit difficult to strip this wire because of it being so thin. Tinning it with solder gives it some substance.

I used the "extra hands" to solder it and a piece of heat shrink tubing. Worked great this way. Note though I am only using it for one device and not a hub; so the draw is not really much.

Are there mini-sockets for two antennae on the WLAN board? will have to check.

These are standard sized sockets; same as in a laptop WLAN card. I have a picture of the WLAN USB card and two antennas somewhere on another post here. The USB stick does draw some power in that its gets warm when running.

I am using an external DAC for my smoothwall box in the master bedroom. That said the "other" external USB stuff is an ASIX external NIC card for the Seabios'd Jogglers. You can also wire up a DAC right to the motherboard as the connections are there for digital audio. I am using the same 4 wires connected to the USB pins as you have posted from the Wiki. I did not try the direct DAC output traces though. (2 separate things here; DAC direct connect to the Joggler motherboard and another USB connection on the motherboard.

Another side note. I am using a POE standard 48V switch injector for 4 Jogglers right now. On the Joggler side I am using a TP-Link power splitter. It has a 12/5 VDC switch on it. It is very small; even smaller than the AC adapter. This allows me to place a Joggler where I do not have an AC power.

I auto dim the screens and shut them off at night via some scripting. That said the Joggler runs very cool without the LCD screen at full brightness.

I think my issue here with wireless is that I have too much RF in the house of different frequencies which in itself is causing RF signal issues. That and the proximity of all of the neighbors wireless stuff causes issues. That said I utilize an Ubiquiti wireless access point in the attic. This has replaced the DD-WRT Buffalo dedicated wireless access point.

[jkn]

Hi Pete

I think we've been talking at cross-purposes slightly - though to good effect. It was the PCB trace highlighted in the following image I was worried about:

http://www.nicorp.co.uk/download/joggler_usb2_pcb.jpg

Having had a closer look again at the Joggler and reminded myself of the separate WLAN card, with its own two antennae, I realise that this PCB trace can't be an antenna track (I've been hacking some 802.11 PCMCIA cards recently and they often have a trace like the one shown for one of the antenna)

So hopefully there will be no problem, though I do wonder what that trace is for. I will probably use a mixture of double-sided tape and either hot-melt glue or epoxy to hold the USB connector to the PCB/casework.

I have checked out a few of your other postings here and elsewhere and can see the USB-NIC device you put on the back. My USB DAC is similarly small, and I may just use double-sided tape to fasten it to the back of the Joggler, to begin with at least, wiring directly to the third USB traces as you have done.

I hadn't come across 'POE injectors' before, thanks for the info. I don't have an immediate use for them but it's always good to know...

I auto dim the screens and shut them off at night via some scripting. That said the Joggler runs very cool without the LCD screen at full brightness.

Could you say some more about this? What with the Joggler having no cron etc ...

Cheers
jon N

[pete]

It was the PCB trace highlighted in the following image I was worried about:

I did notice that you were talking about a trace on the motherboard. That said my conversation went to the USB stick. Personally I wouldn't use any traces on the motherboard as it appears to be a triple layered board.

You are limited relating to the speed and size of the interior flash rom. That said 1 Gb is really tight. I am currently playing with an OpenFrame2 with 2GB of memory. I have redone the partitions using the original base OS and pieces of PnP3. That said there really isn't enough room on the flash.

The best way to take advantage would be to utilize a boot stick with more memory on it running Linux, Android or Windows via an EFI boot.

I am doing stuff with XP and using a Seabios versus the EFI bios. This is totally a bit different as I am using the PATA port and USB ports inside to boot XP with a new base of 16Gb. I guess you could also utilize the pata port in EFI and once booted do a chroot to it for more space.

There are autodim features in PnP3 and SP OS.

The TP-Link device is just a standard POE connection on one side (48VAC) and a passthru of standard network and power (5VDC).

http://www.tp-link.com/us/products/deta ... OE200#spec

My preferences for POE and Home automation are related to in wall or table touchscreens. I do utilize wireless tablets (a whole different world though).

[pete]

I did notice that the little DECT antenna either soldered or using a connector is like a mini dipole of sorts and goes to the top of the case; soldered in the middle to two wires that run to either side of the case.