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[Reply #15 on:]

Ok, so you don't really need to use wifi or bt, if the modules are too expensive. You can also use the public frequency ranges (bands ? is this English ?), using something like the XBee, and connect a sixth Arduino to the computer with the receiver, sending serial data through USB.

To save money and loose time, you can also considerer making your own PCBs using the Arduino as a programmer for some Atmega168.

[Reply #16 on:]

reality check: $135 is VERY CHEAP.

You could argue that it's reasonable, but I don't think you can argue that it's "VERY CHEAP".  So let's say you have a wholesale price of $68.50, and let's even go so far as to say you have to pay $30 for the bluetooth (this might not be so reasonable since you should be able to at least get the bluetooth for wholesale prices, but sure, let's go with it worst case for argument's sake).  That leaves an effective wholesale price of $38 for a standard Arduino board, right?  The cost of the components, PCB, and manufacturing are probably a quarter to a half of this price.  If it ends up being half, the sale price is what you should reasonably expect the manufacturer to charge, but that still doesn't make the price reasonable in an absolute sense if the manufacturer is paying way too much for his components (and I'm not saying that's happening here, by the way).  If it ends up being a quarter, that makes the wholesale price slightly high in my opinion.

I don't know the details so this is just speculation, but as a consumer I think I'd probably consider the board slightly overpriced for what I'd be getting.  Would I still buy it?  If I didn't have a better alternative solution and there was nothing else like it on the market, sure.

Just my two cents.  I hope this doesn't offend anyone.

- Ben

[Reply #17 on:]

I've been looking at bluetooth for a non-arduino project, and BT is obscenely expensive if you aren't buying in mass production quantities (think wiimote).

Bluetooth is a fairly complex system, requiring a lot of engineering effort, processing power, etc.

The best I was able to find for typical arduino-level hobbyist use was about US$60 per module. The Arduino BT isn't really out of line, price-wise, with what I found in my own research.

To the original poster: XBee may be had cheaper (I don't know, it's worth a look).  BT, as implemented in the Arduino BT, may not even work in a network as you describe, because all of the obscenely expensive BT modules I found were only able to support a single SPP connection (even though the bluetooth protocol allows 60-something).

-j

[Reply #18 on:]

A couple of comments:

Yes the risk of buying 2000 modules is part of what a manufacturer should take on... It would be interesting to find a US manufacturer willing to take on that risk.

The Module used in the Arduino BT is expensive also because you can make it do anything (almost)

You can handle 7 concurrent connections using an "API mode" and you can create scatternets, i.e. networks of more than 7 devices.

There is a very ingenious hungarian guy who configure it as a bluetooth headset and used it to turn a rotary phone into a mobile phone heaset.

Next year they promised the firmware will do HID as well which means mouse/keyboard emulation

In europe 79EUR it's a lot but it's not crazy...

I'm sorry the dollar is going down so fast...
email ben.bernanke@federalreserve.gov  for further info

[Reply #19 on:]

reality check: $135 is VERY CHEAP.  Split the retail price in half to find approximate wholesale: 68.50. Subtract a ~$30 Bluetooth module and you don't have a whole lot of $ left. Compared to the alternatives, it is very reasonably priced.

To be clear, I don't think the BT is overpriced in the sense that I don't think anyone is making that much profit on it.  And from what I understand, the retail markup is nowhere near 50% (otherwise you'd see someone buy 100 for $68.50 each and sell them on eBay for $100 each).

But, while it really does cost them $135 to get this product into the market, when you compare it with what's available in the computer world, $135 is not very cheap for what you get.  

If the Arduino team's choice is to make it available for $135 or not even attempt to offer it, I applaud them for making the option available.

[Reply #20 on:]

$135 is not very cheap for what you get.  

ok... then I'm anxious to see the link for a BT enabled I/O module with 5 analog ins and 12 Digital I/O and Software IDE that sells for less than $139.

$135 is very cheap for what it is.

D

[Reply #21 on:]

ok... then I'm anxious to see the link for a BT enabled I/O module with 5 analog ins and 12 Digital I/O and Software IDE that sells for less than $139.

$135 is very cheap for what it is.

$300 buys an asus eeePC.  Throw in an Arduino Dieci and a cheap BT module for $50 combined and you're at $350, and you have a full-blow sub-notebook PC as well as all the functionality of an ArduinoBT.  You get everything you just asked for, plus wifi (and libraries for a full TCP/IP stack, a web server, etc), a 7" 800x480 colour LCD screen, a megapixel webcam, a 5Ah Li-ion battery and charger, a USB host controller, a few gig of storage, a 1GHz co-processor.  All that and it's 2.5 times the price of the Arduino BT.  Plus it can run your whole software IDE for in the field fixes.

I really don't want this post to come off as sounding anti ArduinoBT though.  I do think the Ardunio team has done a great job bringing it to market at as low a price tag as they have.  All I am trying to say here is that it is not "cheap".  My point here is just that it's silly to call $135 for "a BT enabled I/O module" cheap.

[Reply #22 on:]

Lantronix do WiFi modules - not cheap, but may offer you something additional to make it worthwhile.

Mike

[Reply #23 on:]

Hi,

Read the information about the Bluegiga WT11 and then all the other BT stuff from other companies. Then you will know that the WT11 is the better device and a very professional choice for the ArduinoBT.

If you fry the Atmel processor and the WT11 is still working, put it in an oven and increase the temperature (look up the temps) for desoldering. It's worth to save the WT11, it is a precious device for other purpose.

Just my few cents.

[Reply #24 on:]

I am not familiar with the DCC protocol so pardon if I'm all wrong.

If there is possible to have an arduino interpret the DCC signal, it would be possible to have the arduinos at the trains encode the original signal with additional values, and an arduino at the control that would decode the signal before passing it on in its original form to the control.

Or?

My initial idea, knowing nothing about the problem :-?

[Reply #25 on:]

The ardino essentially operates on a serial port (I haven't look at the BT version to see what it does beyond that, if anything.)  That means that you can create your own "ArduinoBT" using a Bluetooth-to-serial module.  Unfortunately, serial has mostly disappeared from the consumer world, and these are not the ultra-cheap mass-produced items like your $9 USB/bluetooth adapters.   A quick look around put them at $50+ !

Now, for your wireless application, you don't need the arduino to be fully wireless like the ArduinoBT; you just need it to have wireless communications capabilities.    There are lots of relatively cheap wireless modules aimed at this sort of thing.  ANT, Zigbee, bare radio, etc.  Using them will be a lot harder than using an Ardunino BT, but a lot cheaper too.  I've heard good things about the Maxstream "xbee" modules, and it looks like there is a bunch of info here: http://www.arduino.cc/playground/Main/InterfacingWithHardware#wireless  (I guess that there is an xBee shield, too...)

[Reply #26 on:]

Here's how the price for all of the items in this niche market are calculated:

[size=12](R&D Cost + Production Cost + Profit Margin) / Demand = Price[/size]

R&D Cost
This is high.  Implementing a full BT stack is actually pretty complex.

Production Cost
Admittedly, pretty low (this is the point you're arguing)

Profit Margin
I'm not mad at anyone for making a dollar, especially if you're the only person doing something well in a niche market (e.g. Arduino BT).

Demand
Very low.  This is small run, special use prototyping stuff man...

[Reply #27 on:]

There's more than that defining the price of this BT modules. The problem is that the cheap USB dongles are almost only a RF module connected to USB: The whole Bluetooth stack is supported by the PC's drivers (using it's CPU and RAM).
On the other hand, this 'serial bluetooth modules' are little self-contained hardware modules with an embedded bluetooth parser and stack, which enables a very simple usage and minimal processing from the uP (in this case, the AVR).