Bluetooth module EPBMX-02A01 (please help)

Hello all,

I have just bought this bluetooth module from seeed studios

http://www.seeedstudio.com/depot/serial-port-bluetooth-module-slave-p-501.html?cPath=2

But I am not very confortable with the arduino serial connection pins and would like to hear some advice from you guys before frying my new toy ;D

I am a bit confused specifically with the Arduino RX/TX pins:

1 - can I connect stuff like this module directly into pins 0 and 1 or do I need to make some kind of adapter? resistors perhaps?

2 - since it will share the comm pins used by the onboard FTDI USB chip, will I be able to use the USB port while the module is connected or perhaps some kind of interference will happen? do I need to somehow electrically disable any of them to use the other? do I need to remove the module in order to be able to use the USB connection?

3 - as the module is powered by 3.3v (which is easy to get from the arduino board) will it be a problem from RX/TX pins point of view? can arduino's or FTDI's 5V levels harm the 3.3V module?

Thanks (a lot) in advance, :) Kind regards, Mauricio

1) because of the 3.3 v issue you will need some sort of level shifting.

2) they would interfere. You could hook the bluetooth module to other pins and use software serial.

3) see 1. The receive data pin could be connected directly but you will need to drop the arduino's transmit data pin - something as simple as a voltage divider will do.

I believe there are forums and Q&A on the seeed site and you might want to look there but post your progress here.

Hello Bill

Thanks a lot for the fast reply!

Like you suggested I will try with a voltage divider ( 4k7 / 10k ~= 2/3 ). No explosions this time :smiley:

But I was wondering: will the atmega be able to recognize a signal < 3.3V as HIGH? I read somewhere the limit is 0.6*Vcc = 3V…

I will test and post the results later.

Thanks again
Best regards,