All the geeky stuff that gets me hot.

Monday, December 12, 2005

Adding Internal Bluetooth

I just bought a used Dell CPx laptop. It's not that fast but it gets the job done. I have a Bluetooth cell phone that I wanted to use as a wireless modem when I can't find a Wi-Fi hotspot. The CPx only has one USB port on the back but it shows two of them in the device manager. Inspired by TnkGrl I decided to try and tap the unused USB port and add a Bluetooth module internally. This would eliminate having the annoying dongle on the back of the laptop and also leave the USB port available for other uses.

Since the CPx is a fairly big laptop there is a little bit of room to play around with inside and I decided to try and keep the Bluetooth dongle as stock as I possibly could. TnkGrl had to remove the USB connector on her module for space reasons but I would rather leave it unmodified if possible. I had a USB-PS2 adapter that I wasn't using so I ripped it apart and got the center portion of the USB connector. This together with unsnapping the case of the Bluetooth dongle led to a very thin package although you can see the USB connector effectively doubles its length. If I didn't have as much space to play with removing the connector would mean you could fit this just about anywhere. I found a nice empty spot right under the palmrest and between the battery and CD drive. I had to cut a little notch out so the wires could slip through but its not visible from the outside.

Now that I had a good mounting spot for the Bluetooth module I had to figure out how to hook it up. I followed the traces from the existing USB connector and they seemed to go to an Intel chip that had PCIset written on it. It also had FW82371MB across the top and after a little bit of searching I came across the datasheet for it. It indeed did have two USB port built in. By examining the datasheet I found the USB pins that I needed. The chip has a XY coordinate system for its pins. The pins in red are what I needed to tap into. Actually finding the pins was nice but pretty much useless, there's no way I could get next to the chip to attach any wires, all the connections were hidden. By following the traces from the original USB connector I noticed that they went to the docking station connector first then to the chipset. This makes sense because normally with the USB in the back you have to remove any devices before you can dock the laptop. I know the docking station has two USB port instead of one so I figured they just added the connector on the docking station to the existing USB hub. Why they didn't add two ports on the back of the laptop I'll never know but I wouldn't be surprised if it was simply to help the sales of the docking station.

I took power for the new USB port from the existing port since the chipset has a specific power plane that is used for the USB system. The data pins I got from tapping the docking station connector. The wire I used was from an old PS2 mouse; the mouse cable has four different colored wires the perfect size for what I needed. I ran the wires up over the top of the board but that was probably a bad idea, next time I would run them underneath to keep them out of the way.

With everything connected it was time to test it out. Success!! I had a few issues at first because I didn't have good connections but once I fixed them it worked fine. Here it is all wired up and nestled in its new home. I ended up running some extra wire to the connector then folding it over to get it to sit nicely in the opening. I thought I might have to pad it a bit to stop it from rattling but the extra wire took care of that for me.

I plugged in a USB thumb drive in the back and it still worked fine. Here's the details for the USB hub now showing two devices connected.

The only downside to this hack is that because of the way the docking station works you will only be able to use one of the USB ports on it since one will always be used for the Bluetooth. I don't have a docking station so that doesn't really matter to me. It's much more useful have the second port all the time instead of just with the docking station.

Because I used a standard USB connector I could switch out the Bluetooth with a Wi-Fi adapter if I found that to be more useful (assuming I could cram it inside somewhere).


  • so genius, when do we invent our "free" wi fi locator :)

    By Blogger m, at 9:48 PM CST  

  • What bluetooth module did you use? You never mentioned which one. I can't remember my blog password. Reply to Thanks.

    By Anonymous Anonymous, at 6:21 AM CST  

  • I used the Zonet ZUB6111C USB Bluetooth module. They are about the smallest bluetooth dongle you can find. They are pretty cheap also, about $15-20.

    By Blogger TomTheGeek, at 1:59 PM CST  

  • Excellent. I cam across this jewel via, and thought I'd give it a go. As it turns out, I too have a Dell CPx, but would prefer internal wifi over bluetooth. So I can follow your directions mostly, but it'd be helpful if you could follow up with the USB lead labels on your pictures. I had assumed that red equaled +power (USB pin#1) while black off of the USB was USB pin#4 ground. Correspondingly, I assumed that the red wire was +data (USB pin #3) and black was -data pin#2. (Pin numbers here ) Anyway, I'm not having any luck with getting the USB dongle to work and as I'm not 100% sure that I have it wired correctly I'm reluctant to troubleshoot further until I'm sure of which lead is which. (Yeah, I could take a multimeter to the power leads, but I'm a little leery of connecting things while the laptop is running for fear of shorting the motherboard.) Any clarification would be much appreciated. Thanks again!

    By Anonymous Anonymous, at 11:55 PM CST  

  • I used four different colored wires: Red, Black, Orange, and Brown. Red is +5v and Black is ground, both coming from the existing USB connector. They go to pins 1 and 4 respectively using the pin diagram. The data pins I just swapped around until it worked but it looks like the brown wire is +data and goes to pin 3. Therefore orange is -data and goes to pin 2. The picture of the docking connector is pretty clear so you should be able to count out the pins to find the right ones. If you get those mixed up it shouldn't matter much, it just won't work. There are traces that go from the existing USB to the docking connector then to the chipset, the unused USB pins are right next to those. They go to about the same place as the other traces but stop at the docking connector. I had to pull up the "DIMM A" sticker to follow the traces.

    Let me know how it works out!

    By Blogger TomTheGeek, at 9:44 AM CST  

  • Success! (I'm the guy that posted above.) My initial error was in reversing the + and - leads. The wifi USB dongle got really hot and failed to work (as one would expect). Luckly no lasting damage was done as everything is working now that I've correctly attached the leads. The take home message here is that I was able to incorrectly hook up the leads in every possible way without damaging anything. (As always kids, this is at your own risk and may not apply to non-CPx laptops.) I couldn't fit the dongle inside the little space that you got the bluetooth module in so I just stuck it inside the unused media bay. Anyway, thanks Tom!

    By Anonymous Anonymous, at 9:56 PM CST  

  • Nice work! And I'm glad my mod was helpful to someone else...

    By Anonymous Anonymous, at 6:18 PM CDT  

  • Hi, I would like to know if there is any standards like IEEE standards for bluetooth Dongle LED behaviour? If there is, please email me at

    By Anonymous Anonymous, at 9:37 AM CDT  

  • Bluetooth dongle LED standards? I doubt there is such a thing. It's up to the manufacturer to decide how to make the LED work, or even to have one at all. My Zonet dongles just have a solid blue light while my Microsoft dongle doesn't have a LED at all.

    By Blogger TomTheGeek, at 12:03 PM CDT  

  • Congrats on the neat hack. Me having same agging CPxJ laptop and your post got me thinking on sticking a mini USB hub on the media bay (currently holding a never used floppy disk drive) to get "built-in" 802.11g and Bluetooth on this old thing. I will have to crack it open to replace a broken fan so I would like you to tell me if this idea is doable.
    Also I'd would like to know if yours is affected by the so called 8ik keyboard issue, and if so if you've managed to cure that.
    Thanks again, and if you ever answer that would be highly appreciated.

    By Blogger alex_mayorga, at 9:00 PM CDT  

  • Well Alex it's hard to say but in theory it seems like it should work.

    Funny you should mention the 8ik keyboard problem, I am in fact having that same problem. It usually works for a little while when I reseat the keyboard connector on the motherboard but never for long. It's bugging me pretty badly so I eventually may try and figure out a fix. If I find a solution you can be sure I'll post it.

    By Blogger TomTheGeek, at 11:30 PM CDT  

  • Even in 2007 still VERY nice!!! THX!

    By Anonymous Anonymous, at 11:48 AM CDT  

  • ok i am confused do laptops come with bluetooth? because my laptop is an Acer Aspire 3690 and it has a bluetooth button, and when i push it, it says no bluetooth device. So i dont know what to do. Can you please help me?

    By Anonymous Anonymous, at 11:42 PM CDT  

  • Two q's (A) how do you use a phone as a modem? (B)how do you tell if your laptop has internal usb stuff and (C) where do you get a bt module?

    someone email me plz at

    By Blogger Unknown, at 1:16 PM CDT  

  • I have a Dell Inspiron 4150 and I want to add internal Bluetooth. My question is this:

    (1) I found USB VD1+/- and USB VD2+/- Pins in the Docking Connector. Where should I connect? My guess is USB_VD2+/- since USB_VD1+/- is the one that is available without the Docking Station.

    (2) Where should I get the +5V DC for Pin #1 of the new USB#2 that will power the Bluetooth? Is there a specific "pin" in the Docking Port that can be used for this second USB?

    The reason why I am asking is because I use the built in USB port to give extra power to a PCMCIA (with 2 USB2) card. I know that the built in USB can only provide 500 mA and it maxes out with the card I use to have USB2 speed. So, which pin is the +5V for the USB ports in the Docking Station. (I can email you the pin layout...since I am not a pro I couldn't figure it out.)

    (3) I guess I can get the ground from basically anywhere...???

    Please help me out my email is

    By Blogger Unknown, at 5:05 PM CST  

  • I have a broken mobile phone with a bluetooth.
    I am wondering if I can do something similar, re-using the Bluetooh from my mobile.

    By Anonymous Anonymous, at 12:30 AM CDT  

  • thanks for this, i converted my latitude cpt into a photo frame, but i destroyed the only usb port. now i have a hub soldered on to there.

    By Blogger Unknown, at 7:17 PM CST  

  • I have Bluetooth constantly running on my new Lenova laptop but I don't have Bluetooth. Should and can I disable it until I decide to get a Bluetooth phone?

    By Blogger Bweez, at 1:52 PM CDT  

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