Stuffing Serial Bluetooth Module Inside C1k Casing

[Mjolinor]

I am going to bid on 10 of these
http://cgi.ebay.co.uk/New-OEM-Complete-Blu...1QQcmdZViewItem

Anyone in the UK want some and I'll post them out when they arrive?

Don't mind doing Europe as well but it will probably be cheaper to buy them yourself with postage costs.

[albertr]

Looks like Ericsson is liquidating it, I saw quite a few offering of them on a reel. I assume you read the datasheet and know that they require external 50Ohm antenna?
-albertr

[Mjolinor]

I assume you read the datasheet and know that they require external 50Ohm antenna?
-albertr
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Yup. I'll make the antenna

[albertr]

I need a help from someone with experience in electronic engineering... I'd like  to implement some power switching circuit thru PNP transistor (or MOS FET?) for built-in Wi-Fi and BT modules. I think I found GPIO lines that could be used to control the switch, but need a help with schemantics and advise on what kind of transistor to use.

Vin and Vout would be either 3.3V or 5V, and max current would be about 500-650mA @ 5V. Also I'd like to minimize any parasitic effects and power drain. Switching speed is not important.
-albertr

[albertr]

Nevermind, I think I got it.
-albertr

[Da_Blitz]

All you need is a resistor and a transitor the resisistor sits between the transistor and thi IO pin, you wauld also want a high gain transistor ro arange 2 transistors in a darlington array

[albertr]

About your concerns about 3850 power dissipation: if it powered from 5V rails we can assume that it will be in 4.9 - 5.6V range.  For input voltage below 5.17V power dissipation will be 0.5A * 0.17V = 85mW which will get the chip slightly warm.
At input of 5.6V it will be 0.5A * 0.6V = 300mW which isn't also very high.  Unfortunately, datasheet doesn't specify case thermal resistance to ambient so I can only guess that the chip temperature will be within 60C which is well in range of working
temperature.  In addition, this IC have thermal protection, so it should be safe to draw 500mA from it.

I replaced the resistor with a 1K one, but it looks like there might be a problem for this regulator to supply high current. I've tried two different wi-fi dongles, and both of them seem to have problems when powered from it.
-albertr

[albertr]

Well, scratch that - the problem seemed to be unrelated to power supply. I got the internal wi-fi module working when powered from that regulator.
-albertr

[JohnX]

That's great! I can't wait to hear how the reception once the Zaurus is put back together. This is making me very happy to have a C1000.

[Boris]

Well, scratch that - the problem seemed to be unrelated to power supply. I got the internal wi-fi module working when powered from that regulator.

Ok.  You may try to measure voltages before and after 3850 to get the picture.   If that will not reveal any problems, then the problem might be in too large voltage spikes on USB power line during various modes of operation.  These can be identfied only with a scope.

[albertr]

Thanks, Boris! Unfortunately, I don't have the o'scope. But anyway, it seems to be working for two days in a row now - over 1GB of data transferred over wi-fi.
ZD1211 gets pretty hot, but so far it seems stable. I attached its metal electromagnetic shield (that covers RF) to Zaurus's metal plate under the keypad. Not sure if it's helping to dissipate the heat, since the other side of it (where ZD1211 soldered to) gets pretty hot too.
-albertr

[speculatrix]

the auction closed, and not many bidders - I went for three of them, on the basis that there's one to hack, one for real work, and one spare just in case!

I'll let you know when mine arrive.

[Da_Blitz]

I just had an evil thoght, scince no one uses the serial port on the back and it is TTL, why not do an internal gprs modem hack using an old doner phone (clamshell without screen or batt, MOBO only)

i am running out of space and i havent even started soldering yet (thogh i did add bluetooth internally to 2 linksys NSLU's)

im thinking a docking staitoin as i want 2 wifi cards and a bluetooth w/ external antennas )3 of them ) and gprs, might as well put my external battery in there as well to power the beast

considering that my USB hub and bluetooth card are smaller than a CF card when the 2 are placed next to each other (got to love sydney's china town) and tho mobile being about the thickness of a CF card then my doking station wont be 2 small, if i could just find someone wh o could redesign the bottom half of the case then i would be really happy

[Torsten Wagner]

Hi,

Just followed the thread recently and it sounds quite interesting. I'm not very deeply involved in the hardware of the Z.  Therefore, I just have some question to understand and hopefully further help in development.

1. Is there enough space to add beside the WLAN and Bluetooth-Card an additional memory stick? I really like to see my C1000 with a internal storage of more then 1 GB.

2. Did you plane to use one USB port of the Zaurus with an additional USB-Hub to connect all these devices with the Zaurus or will you use all USB ports of the Zaurus itself? Did you manage to find out for what the ports (which are used for USB) of the Zaurus are used instead (since they have normally double or triple functions)

3. Any idea about the overall power consumption? One problem which maybe even leads Sharp to include no internal devices is the ratio between weight, size / battery life. It is still a PDA and should fit size and weight criteria. Our Zaurus devices are already on the upper limit in this case. Small a light device requires small batteries and therefore low power consumption for useable battery lifetimes. No space (in terms of electricity) for additional gadgets?!?

Personal I believe that the battery of the Zaurus is already somewhat too small in capacity for a PDA. Intensive use with sometimes WLAN force me to recharge the Zaurus every second day - sometimes daily. It would cut the fun if I have to charge it twice a day because of internal Bluetooth, WLAN etc. Therefore, if we like to integrate more devices, we should check whether we have to tune the power unit as well.

4. For the heating effects of the power regulator (?). As far as I remember the pictures correctly, there was still little space. Maybe it helps to use a little copper sheet together with some thermal grease.

I will try to support this project. Unfortunately I have just one Zaurus which I daily use. Disassembling this unit is not really what I want.
However, I'm sitting here in a lab with a huge bunch of electronic tools and devices. Even a PCB-milling-drilling-whatever machine can be used here.
Therefore, if I can assist you, I will try my best.

Best regards

Torsten

[Da_Blitz]

I am going down the hub path as it allows me to avoid a couplu of issues such as turning power to a device off (ass the hub does this, i only have to turn off the hub)

there is not much room in the case, if you have a c1000 then you are in luck as you have the internal CF slot free, otherwise you can have a bluetooth dongle and thas about it, you can gain more space if you dont want the second CF slot (the external one) and want 2 full sized USB host ports instead or dump the SD slot and gain a bit of space

with the C3000 you might want to consider a usb socket somewhere or build a docking station

the C100 could have bluetooth wifi and storage if you boght a small sized flash disk and got creative but at tah point you would need a hub

a soulution to bad battery life is an external battery pack but not everyone likes this