Bluetooth development chips

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Hello all,

I have recently acquired a bluetooth development kit (TDK's blue2i +
USB adaptor). I have successfully connected the serial ports and
transferred and received the data at 9600 baud. I want to use the
serial module in customized hardware. But the serial unit is very
expensive (around 92 pounds). What alternative chips do I have at my
disposal which will provide me with a serial - bluetooth interface? My
only requirement is a bridge between uart (well, only RX/TX) and
bluetooth protocol.

Since I plan to interface the chip with a microcontroller, I do not
need a RS232 level converter of that sort either.

So which chips would allow me a bluetooth - I2C or SPI or Serial or USB
for that matter interface? If I want to remove the serial interface
also and just go for a simple command received via bluetooth, how can I
do that with a micro-controller present in my circuit?

Any feedback much appreciated,

Thanks in advance,

Mak


Re: Bluetooth development chips
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What quantities are you looking at? 92 pounds is expensive indeed. We pay
about 65 euro's for that module in small qty's (20's), which is appr. 43 ukp
without VAT.

Meindert



Re: Bluetooth development chips
Indeed a significant difference in prices. Since I am just exploring
ideas, I am not sure about the quantity. But if we consider employing
the technology in toll plazas (is it feasible?) on highways and
motorways as well as the vehicles, the quantity will significantly
increase to thousands of units.

Any effort to implement it in home appliances and automation would
dictate a much simpler and cheaper variant. Any ideas on what type of
chips are out there meeting these criteria?

Mak


Re: Bluetooth development chips
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Bluetooth dongles are pretty reasonable in the UK (15 GBP). Why not try
selecting a device that has open linux support, then reverse engineering
from there.

Bluetooth DEVKITs were very expensive 12-18months ago, so I opted to go
for full wireless 802.11b and WLUSB instead.

Enjoy.

Re: Bluetooth development chips
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A cheap dongle requires a USB host and enough power to run the entire BT
stack. The TDK TRBLU20 modules have this stack internal, which allows your
host to be much much simpler and cheaper.
Oh, and the TRBLU20 modules are class 1 (100m range), the cheap USB dongles
are mostly class 2 (10m range).

Meindert



Re: Bluetooth development chips
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Mak, Meindert Sprang has a fair point, my suggestion is based on a USB
host (like you mentioned). If you are homebrewing, deconstructing a
bluetooth dongle with opensource drivers makes good financial sense.
Remember: interfacing with USB can occur over copper tracks...

The BT stack is generic for use in various applications, you should feel
free to extract what ever areas of the stack apply to your application.
Others have implemented the stack on micro-controllers long before now,
size and complexity depends on YOUR APPLICATION.

Er, yes Class1 and Class2 USBs at less than 92 euro.

If you are time limited and need to get a product to market, go with the
TDK option. Otherwise use that huge PC engine to reduce your R&D costs.




Re: Bluetooth development chips
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At that quantity, the price of a TRBLU20 module (serial I/O at TTL level) is
about 42 euro at a decent distributor.

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Remember, if you go your own route with Bluetooth, you're facing hugh
certification costs.

Meindert



Re: Bluetooth development chips
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IMHO: If certification is important, then the TRBLU20 represents a
budget solution to your application. If your homebrewing, anything at
quantity may sound like a bad idea.

Re: Bluetooth development chips
Sigh, Thanks for all the ideas. I was thinking in the lines of getting
a bluetooth protocol chip (any suggestions on that?) and designing an
RF antenna on my own, pretty much like reverse engineering the serial
module and provide USB circuitry to that (any chips used commercially
which implement USB 1.1 or USB 2.0 protocol on hardware?), however the
certification costs is a practical issue.

TDK's module is just too expensive to design a simple home automation
circuit (yes 42 Euros are a LOT :) )

Should I just start looking for AM RX/TX circuits, rough requirements
could be 1kbits of data transferred at 1kbps or higher.

Thanks,

Mak


Re: Bluetooth development chips
Hello,

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perhaps have a look at chipcon's chips (perhaps especially the CC2420). If
you need links to datasheets, have a look at my page at http://www.clibb.de
They transfer 250 kbit/s, around 70 Meters i think, support encryption if
needed. Price is another topic: I bought a few modules from microchip, with
completely soldered RF part including antenna, so only need to connect it to
your microcontroller via a SPI port. Payed 30 Euro per module. If you buy
only the chips itself, you get it much cheaper. Pay attention that you can
use it (perhaps inofficially, illegal) in simple Tx / Rx mode, or you need a
Zigbee stack and ceritfication too.

Regards,

        Martin



Re: Bluetooth development chips

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Hi,

Try http://rfdesign.co.za . They have a bluetooth module that
includes the stack for ZAR 250, which is about GBP 20. I am
sure you should be able to find the same module in the UK for an
even lower price.

Regards
   Anton Erasmus


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