Integrated Bluetooth on a Jornada 720: Project BT J7xx

I got to thinking the last time I had a 720 apart about all that lovely space taken up in the case by the modem card. I speculate that few of us make any sort of use the modem, except in the most dire situations.

I propose the following: Since the modem most likely is driven via a RS232 circuit, would it not be feasible to remove it, and replace it with Bluetooth (which is also driven at a relatively low transmission speed and can be driven through 232 TTL circuits) either in the form of an internal application specific circuit board with an OEM module (like that found in notebooks) or a circuit board making use of the increasingly popular SDIO cards that recent Palms have support for.

Clearly, a driver would have to be written. Any takers to the idea?

cool idea!!!
i wish i wouldn't be useless at hardware hacking... or at writing drivers

There exists a few very thin bluetooth modules, and as such I was thinking about putting one up behind the screen. Seems an odd place, but it would mean keeping the modem. Just where I'd get a serial line, I'm not sure. Possibly fasten it into an existing line with a switch to toggle between modem/bluetooth or IR/bluetooth or something.

If it is true that the modem is on RS232, then you could buy an RS232 Bluetooth adapter (Socket makes one IIRC), take it apart, and "connect" it to the modem port. The final step is to configure the driver to use that modem port.

As a reminder and potential alternative idea (for those not wanting to take the case apart and/or lose the modem) it's important to remember that the sync port on the back of the Jornada is serial. However, I'm not sure of the maximum throughput. I recall reading that the external keyboard is a serial device running at only 9600 baud. I don't know if the sync runs faster than that, but I imagine that it does. This is actually probably the easier option for serial to Bluetooth. The major issue, besides drivers, is the goofy connector. Bottom line is that you'd likely have to cannibalize a serial sync cable for it's connector. Resources follow:

Sync Port and Cradle serial pinouts
http://www.lowlevel.cz/log/pivot/entry.php?id=41

ESD02 OEM serial bluetooth module
http://www.lemosint.com/scripts/bluetooth.asp

Jornada 720 Hardware Configuration and Addressing
http://www.handhelds.org/download/projects/jornada/720/jornada720.txt

Edited by oflash 2006-07-03 5:48 PM

the bt-rs232 is a great idea as a hardware solution, but the driver software has to be able to do everything that normal bt does, pairing, dun, and whatnot.

oflash, it can sync at the max 115k.

On the topic of Bluetooth I think that on the whole, the hardware will be more of a challenge to put together than the driver. And I don't think that the software will be that hard for the Facorites. Bluetooth support is in the more recent builds of CE (4.1 and up?) and I've come across at least one device with a USB interface designed to be used on a CE device with CE's built in drivers.

I think that the ease of interfacing serial is clear in that nearly all the interfaces on the Jornadas make use of it, that is keyboard, touchscreen, sync, modem, infrared and external keyboard. All of these devices are limited to the 115Kb Tx Rx limit as far as I can tell. The Conexant RP56LD is a hardware chip facilitating a software modem. All commands are provided by the driver.

Conexant Modem documentation:
http://ev.dhs.org/dreamcast/modemDocs/

eVC Libraries for serial Bluetooth
http://www.modemtools.com/programs/MarshallSoft-Computing-Inc/Win-CE-Std-Serial-Comm-Lib-for-eVC.htm

CE Bluetooth SDK information
http://www.extendedsystems.com/web/news_detail.aspx?key=57E0D39871561FB10739DD6CC10DF64A

USB Bluetooth for CE and XP
http://www.windowsfordevices.com/news/NS7948805317.html

More Libraries SDKs?
http://3d2f.com/download/23-857-win-ce-std-serial-comm-lib-for-evc-free-download.shtml

Could we find some sourcecode for the 720 external keyboard driver. Not essential, but helpful I'm sure.



Edited by oflash 2006-07-04 12:45 AM

Alright, let's take this another direction. Can anyone with a 4.2 device send or link to a copy of Bthuart.dll?

Some "CSR based" BT CF card for example Windigo:

http://www.windigosys.com/app_compactflash.htm

work fine with BlueSoleilCE
with next settings : UART 115200 FlowContol - none
I think any serial based CSR BT module can work in Jornada with BlueSoleil. Isnt it?

Edited by 631603921 2006-08-20 10:42 AM

Would something like this work with the 720?

http://www.probyte.fi/catalog/product_info.php?products_id=203

sorry oflash, didnt see your request. as soon as this blackout ceases, i'll check if i have that dll in PB

Thanx Cmonex. Do you think it may have promise?

hi, well, i realized i didnt build an OS with bluetooth support yet. i will do that and will get you the dll. by default only libs are in PB.
it takes me about half an hour or a little more to build a minimal OS, so will get back to you on this

So...what is the verdict on hacking a j720 to put bluetooth in the case? or attaching it to the serial cable?

What about one of these in a PCMCIA compact flash adapter?

Belkin Bluetooth PDA and PC Network Adapter Combo Card

Billionton Compact Flash Bluetooth Adapter

Seems like the existing PPC driver could be modified.