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Topic: Bluetooth chip EXPLODED (or not?) (Read 449 times) previous topic - next topic

D3C3PT1C0N

Nov 17, 2011, 12:28 am Last Edit: Nov 17, 2011, 11:47 am by D3C3PT1C0N Reason: 1
Hi!
Couple of weeks ago i bought a cheap bluetooth module from e-bay.


http://www.ebay.com/itm/TTL-Bluetooth-Module-Arduino-uControllers-/330632884570?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%26itu%3DUA%26otn%3D5%26pmod%3D230689344642%26ps%3D63%26clkid%3D3891958372673248975

When i received it, everything worked well.
Today i soldered some pins to the module and plugged it in to my breadboard.
Then I uploaded sample code to Arduino. After double checking everything, i powered it on. But nothing.

The only thing that works, is that my phone makes successful connection to bluetooth module. I can tell this, because bluetooth module stops blinking (searching, announcing) and my cellphone says it is connected.

I uploaded sample script that should take my compass readings and send them to Arduino as an integer "time led blinks". I also tried another script that worked well before, but no luck.

[font=Verdana]Is it possible, that although bluetooth module creates successful connection to my smartphone, it is not able to send commands to Arduino? [/font]

Someone wrote in another post that bluetooth module's RX, TX work with 3.3V, but Arduino's RX, TX pins work with 5V, so definitely should use resistors.
- Unfortunately I forgot this crucial aspect and connected modules RX / TX straight to Arduino pins  :~



Grumpy_Mike

#1
Nov 17, 2011, 06:57 pm Last Edit: Nov 17, 2011, 07:00 pm by Grumpy_Mike Reason: 1
Quote
Unfortunately I forgot this crucial aspect and connected modules RX / TX straight to Arduino pins

Yes that could explain why the module itself works but you can't communicate with it.

But the web site says:-
Quote
Note:  TX and RX are LVTTL, meaning 3.3V signals.  While I have tested the module extensively directly using the 5V TTL signals (Arduino for example) with no problems, I cannot promise that damage will never occur, and it is therefore recommended to use transistors to interface with a 5V TTL signal.

D3C3PT1C0N

Well... there goes my 11 euros :P
Next time I should read before diving in  :smiley-mr-green:
At least it wasn't Arduino BT , that costs 114,00 € in a local shop.

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