Bluetooth connectivity

I'm looking at ways of connecting Bluetooth capable mobile phone to empeg. The goal would be to establish a GPRS connection and have a low-cost Internet access available in car. However, I haven't figured out an easy way of doing that yet.

Let's start by looking at the interfaces what empeg support:

10Base-T network: It would be possible to connect a Bluetooth Access Point to the network slot, but that only makes sense if the Bluetooth device would support LAN Access Profile. All Bluetooth mobile phones support only Serial Port and Dial-Up Networking Access Profiles.

USB Slave: There are several Bluetooth USB adapters in the market, but as with so many other devices, they only act as USB slaves. As we know, two USB slaves can't communicate without a host - which is missing from empeg. Are there any special USB "hubs" that would solve this kind of problem?

RS-232 serial port: With couple of Bluetooth RS-232 adapters in the market, this would probably be the easiest solution. However, in my case, I have the serial port already hooked up with a GPS receiver. Is anyone aware of RS-232 splitters or dividers which would let i.e. two devices to communicate on the same line with halved bandwith or such? Actually, the TX line could always be attached to the Bluetooth adapter since I only need to receive data from the GPS module. Then, the remaining problem would be to share the RX line among the GPS receiver and Bluetooth adapter.

None of the three options sound like a plug'n'play solution for Bluetooth connectivity -- are there any alternative ideas?

Kim

Hack the sony stalk interface on the radio to act as another serial port or use IR.

-Mike

Sony stalk is not another serial, but analogue (resistive) input. See Sven's description on riocar.org. There is another serial port (inversed TTL levels, IIRC, search for Hugo's correction of my previous post), but it is already used for tuner.

There are, or rather were, multidrop (multipoint) serial interfaces (they were popular for connecting computer terminals and instrumentation once upon the time, approx. in the days of Cinderella ), but they require some kind of protocol, either SW (with addressed packets), or HW (with additional address lines).

There was talk here about defining our own multipoint serial protocol, possibly with an external demultiplexer (adapter to 'ordinary' RS-232). guys@empeg also said they had a design for it (probably for yet another secret OEM project). It kind of died....

There is another serial port (inversed TTL levels, IIRC, search for Hugo's correction of my previous post), but it is already used for tuner.

OK, that is what I was remembering (apparently incorrectly). Could you take over this port when the tuner is not in use?

-Mike

hi !

I thought about some other possibilities:

1) interfacing a microcontroller through ethernet.
I found a very cheap java controller with ethernet + 2 serial ports for 50$ (http://www.ibutton.com/TINI/hardware/index.html)

2) custom interface on the IDE-channel (very interesting for the mk1 owners :)

I only heard about one project, which uses the IDE-interface (somebdy build a SPDIF out on the IDE interface).
But maybe our IDE-guru knows more about this ?
mlord ?

bobo

I think not (if the tuner is installed at all). Perhaps one could build some kind of external switch box with level converters...

10-BaseT:
You can buy a Bluetooth access point for ethernet, which will allow you to connect to the mobile phones. I think, however, that these are designed for using the wap-browser in the phone to access IP network resources.

But. The firmware for the AXIS access points is available, and the access points... run... of course... linux.


Marius (Escort Cab + Mark II)

You could pull the IrDA interface - this goes to an IrDA encoder chip (due to bugs in the SA1100's internal irda encoder). You're then left with a 3.3v-level serial port that will go up to 230,400bps - ideal for bluetooth.

I believe the bluetooth support from Axis for the linux kernel *only* works with serial bluetooth adaptors at the moment - bluetooth over serial is one of the defined methods to talk to a bluetooth transceiver embedded in a system. The Axis stuff allows at least a modem connection, I think.

http://www.blueunplugged.com has modules designed for embedding (see the "development" section) for UKP 85+VAT. Real, external serial modules that are a bit more robust aren't a lot more, though.

Hugo
(who's just got a T68 with bluetooth, replacing his 6210+bluetooth battery)

You could pull the IrDA interface - this goes to an IrDA encoder chip (due to bugs in the SA1100's internal irda encoder). You're then left with a 3.3v-level serial port that will go up to 230,400bps - ideal for bluetooth.

This sounds interesting. How difficulty you think it would be to grab the TxD and RxD lines from the IrDA interface?

http://www.blueunplugged.com has modules designed for embedding (see the "development" section) for UKP 85+VAT.

Nice. Would it simply work if the TxD and RxD lines from the IrDA interface would be connected to i.e. Ericsson ROK 101 008 module (which you referred)? The chip would seem to run on 3.3V logic, so it should be fine.

On software level, this would provide a HCI-level access directly from /ttyS2 which could then utilize i.e. Axis BT stack which provides layers upto RFCOMM which neatly connects to i.e. pppd directly.

This kind of hack would be easiest to do into a small PCB which resides inside empeg for easier connectivity. Otherwise, taking the "second" serial port out of the IrDA interface and carrying it outside of empeg is difficult since the docking connector does not do the job.

Real, external serial modules that are a bit more robust aren't a lot more, though.

Do you have some other links in mind? At least all of the Bluetooth devkits are ridiculously priced. They are usually more than 10 times expensive compared to the Bluetooth core on its own.

Hugo
(who's just got a T68 with bluetooth, replacing his 6210+bluetooth battery)

Drool... I've been looking at the T68 also, seems a way superior to any competitors. Even the upcoming 6310 loses the battle easily.

Kim

FYI, the IRDA encoder is next to the 3.6864MHz xtal just above the RAM chips; it's labelled HSDL7001.

Pin 2 is TX (-from- the strongarm) and pin 3 is RX (-to- the strongarm). You'd have to lift pin 3 from the board to stop the 7001 from driving the line.

You can get 3.3v from pin 16, and ground is on pin 8.

As for external bluetooth modules, try www.brainboxes.com - I've not tried them, but I think they're just bluetooth transceivers in a box...

Hugo

Thanks for all the info, Hugo!

I went ahead and installed the Ericsson BT101008 Bluetooth chip into empeg. So far, I've tested it with Axis's Bluetooth stack and I have gotten a valid BT address and revision info read from the chip.

Once I get my Bluetooth phone, I'll be able to do further tests.

Meanwhile, I posted some installation photos here.

Kim

AMAZING!

So what do you plan on doing with that bluetooth support?

Cool! I've been playing with the (2.4 only) bluez stack a little, but only on a PC at the moment.

Neat job you did though - if you want easier access to the IrDA chip, you can remove its oscillator (very easy) as you've stolen its functional pins anyway :)

Hugo

So what do you plan on doing with that bluetooth support?

Read my first post .

I'm planning to get a Bluetooth enabled mobile phone connected to empeg. Then, empeg can establish Internet connection through the mobile phone's GPRS link. With some additional programming, I can periodically send the car's geographical coordinates from the navigation system to a website or whatever vehicle tracking system. And of course it can fetch the latest weather report or traffic report around the area I'm driving. And what else you were able to do with a Internet connection...

Also, once more and more devices will have Bluetooth chip embedded with various products, it will give opportunity to communicate with those. New PDAs, such as Compaq iPaq H3870 are already Bluetooth enabled.

Kim

I have got a Bluetooth PC-card in my laptop,
and I'd love to run emplode over it :-)

Marius (Escort Cab + Mark II)

Be warned that Bluetooth is not that fast.

It'll be about the speed of a serial port connection.

Marius (Escort Cab + Mark II)

Well, yes - but the serial ports on the SA1100 will do 230,400bps if the thing at the other end can handle it. Bluetooth modules can, for example.

Hugo

Assuming you can control the phone via bluetooth, could you emulate the 'handsfree/headset' profile on the empeg, using the mic in to turn it into a universal bluetooth handsfree kit.

You would get into the car, set your phone to blutooth mode, and then when the phone rings, the empeg mutes, the phone hands the call to the empeg, which using the digital voice stream from the bluetooth module outputs it through it's DA. Meanwhile, the Empeg's Mic input AD'd and sent back along the bluetooth connection to the phone.

Assuming you have got the bluetooth chip talking to the empeg, it would just require the correct protocol to initiate a voice link rather than a data link.

It might even be possible for the phone to send the CLID to the empeg, so the name/number was displayed on the screen before you answer it.

What do you think?

Oli.

MK2a 20GB (at last).

Assuming you can control the phone via bluetooth, could you emulate the 'handsfree/headset' profile on the empeg, using the mic in to turn it into a universal bluetooth handsfree kit.

You would get into the car, set your phone to blutooth mode, and then when the phone rings, the empeg mutes, the phone hands the call to the empeg, which using the digital voice stream from the bluetooth module outputs it through it's DA. Meanwhile, the Empeg's Mic input AD'd and sent back along the bluetooth connection to the phone.

Assuming you have got the bluetooth chip talking to the empeg, it would just require the correct protocol to initiate a voice link rather than a data link.

In principle, it would be possible but the Bluetooth chip I have only supports data link (not voice link) and I only have VCC, RX, TX and GND pins connected to empeg. Even connecting those pins was rather challenging as you need to work with SMD components.

It might even be possible for the phone to send the CLID to the empeg, so the name/number was displayed on the screen before you answer it.

Well, that I've had for couple of months now . In addition, it periodically establishes Internet connection through GPRS to transmit the car's location information to a web page and gets latest traffic report around the major roads I drive.

Kim

Kim, the ericsson 101 008 chip does support voice and the required headset protocol. It has a PCM input/output/sync/clk on pins A1-A4.

It just requires geting the PCM output from the Bluetooth module 'into' the empeg's board. and the same to get a PCM stream off the board from the empeg's Mic sampler, to the input of the Bluetooth module.

Then you could use the UART interface of the bluetooth module to control the phone like you are currently doing, but with the added functionality of a voice-recognition handsfree kit.

The only problem I can see is getting the PCM signal on/off the empeg's board.

Any Ideas?
Oli.