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Hi! I'm new to electronics, but I'll study all basics in a few days, as Arduino makes it quite simple. I have a project on my mind, and while
I study, I want to order a board, which will suit me the best. Can someone advise me the cheapest solution, which will match with those requirements?

1. Small size
2. Need to transmit bluetooth signal
3. Need to receive bluetooth signal (should be seperate part, connected so seperate pin)
4. Needs to have LCD screen

Surely, I'll buy bluetooth transmitter, receiver and LCD screen separately. Though, I still do not know about bluetooth transmitters, I hope they can be bought around at the stores.

Thanks!
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Hi! I'm new to electronics, but I'll study all basics in a few days, as Arduino makes it quite simple. I have a project on my mind, and while
I study, I want to order a board, which will suit me the best. Can someone advise me the cheapest solution, which will match with those requirements?

1. Small size
2. Need to transmit bluetooth signal
3. Need to receive bluetooth signal (should be seperate part, connected so seperate pin)
4. Needs to have LCD screen

Surely, I'll buy bluetooth transmitter, receiver and LCD screen separately. Though, I still do not know about bluetooth transmitters, I hope they can be bought around at the stores.

Thanks!

Small size would be Arduino Mini, Arduino Pro Mini, Arduino Nano or Boarduino. Links further down.
The only Arduino with onboard bluetooth is the Arduino Bluetooth, this is bigger then the above and MUCH more expensive. I would try to find an external Bluetooth transceiver.
There is no Arduino board with on board LCD, but check out this: http://arduino.cc/en/Tutorial/LiquidCrystal

Links to boards mentioned above:
Mini: http://arduino.cc/en/Main/ArduinoBoardMini
Pro Mini: http://arduino.cc/en/Main/ArduinoBoardProMini
Boarduino: http://www.ladyada.net/make/boarduino/
Bluetooth: http://arduino.cc/en/Main/ArduinoBoardBluetooth

I hope this helped a little,
Jan
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Thank you, ArduinoBoardMini seems fine. I guess it has enough pins to fulfill my needs? LCD takes 6 pins, and 2 bluetooth devices takes 2 pins, right? So:

Digital I/O Pins   14 (of which 6 provide PWM output)
Analog Input Pins   8 (of which 4 are broken out onto pins)

should be fine, I guess?

Now I'll just double-check what kind of pins I really need here in the tutorials, as I still do not know difference between I/O and analog pins.
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You can use the Analog pins as digital pins.

analog0 = digital14
analog1 = digital15
...
analog5 = digital19

so to write to analog pin 3, use
Code:
digitalWrite(17, HIGH);

Jan
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A few thoughts, I'll start with the bluetooth.
Bluetooth is not as easy as it seems, especially if you have little to no experience with electronics. If you use a board like this: http://iteadstudio.com/store/index.php?main_page=product_info&cPath=18&products_id=179 or similar, you will need to have use a serial connection to communicate with it. that is digital pins 0 and 1 spoken for there. You will, if, as you said, need two bluetooth units, you will use pins 2 and 3 for the second unit. You will then need an LCD, I would suggest a simple Serially accessible one, http://www.sparkfun.com/products/9393, that takes another two pins. Then you will need to write a buttload of code and somehow use two lots of standard digital pins as software serial ports, not an easy task, but doable. You may then run into issues where the Arduino just isn't fast enough to run three serial streams at once, but I don't know how that works as i have never tried. If you are serious about this project, then please, by all means, do it, I, for one, want to know if its possible.
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Thanks for the replies. Actually, you are right, using 2 Bluetooths would be too much. I've learned LOTS of stuff in the last 2 days, and I actually start getting the idea. So I'll have 1 bluetooth constantly operating, which also will save power. Thanks for pointing to the LCD! I've learned lots about them as well now.

Now, as for another one signal transmitter... Here I've got one question:

At some point, I need to press a button and sent short signal from transmitter to the sensor in front of me. Sensor might be hidden behind a obstacle, that is why I can't use infrared here.

Also, my beam has to be as narrow as possible. ( < 10 degree)

So, I'm planning to use very high frequency + directional antenna to achieve this. As low frequencies will make antenna unreasonably large.

I don't care about 100m or 200m, I need to operate only within 0-10m range.

So, what is most highest frequency I can use? 5Ghz? As far as I learned, there are restrictions by law. What is the optimal solution for me would be? Once again, briefly: I need to sent as narrow as possible beam within 0-10m range.

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Why does the signal have to be such a narrow signal? you might be best to just use a zigbee or xbee as these are 2.4ghz and have low range (<40m).
« Last Edit: February 01, 2011, 03:23:49 am by fliggygeek » Logged

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Why does the signal have to be such a narrow signal? you ming ht be best to just use a zigbee or xbee as these are 2.4ghz and have low range (<40m).

fliggygeek is right. XBee modules are much cheaper then bluetooth in the low range versions. See this: http://www.sparkfun.com/categories/111 and this: http://www.sparkfun.com/tutorials/128

Bluetooth is (as I see it) only needed if you want to communicate with a device that only has bluetooth, like smartphones etc.

Jan
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Thanks! XBee sounds like a good solution. I want to make laser-tag game at my city, but instead of infrared, I want to use higher frequencies, in order to hide sensors behind people clothes.

Infrared beams could be focused with lenses, but here I can use directional antennas only. I guess all I can push from 2.4GHZ is a 30 degree beam (yagi antenna around 15cm).

Maybe it IS possible to screen beam somehow, to make it much more narrower, but I couldn't find anything about that. Well, I guess I should buy two arduino mini boards and 2.4GHZ Xbee, and starting experimenting once I have them. Little by little, something will come up =)
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Remember you need one Xbee as sender and one as receiver.

Also, Xbees are bidirectional.

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Laser tag style with a radio signal, now theres something I havent thought of, its doable too, but it will have it's challenges. Using a yagi might work fine, but I would suggest a small parabolic dish with sheilding all around everything except where you want the signal coming out as most antennas have a fair bit of leakage. Yagi antennas are much less directional than a parabolic dish.
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