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Fez Cerbuino Design Modification


#1

I recently attached a Digi Xbee Wifi Module to the Fez Cerbuino that has the RP-SMA connector. The connector is too close to the USB host port. It’s so close that I have to take of the lock washer and nut just to fit it to the board. I had also purchased a Large RP-SMA antenna which definitely won’t fit.

This is just for someone’s future reference. I think the boards should only come with the vertical Usb Host.

If anyone has any ideas how I can fix this (even with solder) I’d be grateful.


#2

You can remove USB Host connector.


#3

I seriously thought about doing that, but the project has to support usb mass storage (which I was going to write drivers for). If the device doesn’t see the network I just may do that.

Could I connect the USB host port back with 4 wires afterward? Will that affect the signal quality or something?


#4

you could also build/add a header “booster” shield for the xbee port to get it to a height that clears the other parts. This kind of part shadowing is not unusual when you have stackable devices; catering for every possible design is not overly practical or costs you in increased board area to get better clearances.


#5

USB is very sensitive to trace length, so there’s a good chance using wires will cause potential issues. But Cerb family doesn’t support USB Host at this point, so unless you were embarking on that entire driver quest, you may not have a problem by removing the port.


#6

The other option is to remove the RP-SMA connector and attach that one with a wire.


#7

I think people who use Arduino shields with Cerbuino will disagree with you. :wink:


#8

@ Architect, ah shoot that’s right! Well I guess it’s soldering time.


#9

Taken from the Overview Page for the Cerbuino

[quote]The XBee socket automatically brings all sorts of wireless options to the table, including WiFi and ZigBee. Note that there is a size restriction on the physical size of XBee modules that can be used. Whip antenna, chip antenna, UFL antenna fit well, but the ones with RPSMA connector do not. Also plan your XBee selection well if you are planning on using full-size shields.
[/quote]


#10

[/quote]+1 for Reading the manual.


#11

Can you use a female header strip between the socket on the board and the pins on the plugin device to raise it up a little?


#12

@ Mike, No I don’t have that type of header.


#13

#14

That does work. I’ve done it myself but the fit is a little sloppy due to the pin being thin. I hot melt glue them in place and this has worked well.


#15

I’ll go with the option of desoldering the RP-SMA connector and attaching it to a case.

Thanks for the suggestions all.


#16

Make sure you use coax cable with an impedance of 50 ohms. You might get away with a really short wire but not advisable.


#17

So shielded coax cable 50Ohm impedance. When you say short, is 6 inches to much?


#18

At 6 inches you are going to need coax. I was thinking more like 10-20mm. Even then, I would still go with coax.