Interfacing a GPRS module with Arduino

Projects Networking, Protocols, and Devices
1

Hello everybody, i bought a GPRS MODEM from the DealExtreme website.
I would like to interface it with the Arduino DuemilaNove using this schematics:

http://finch.am/projects/arduinogsm/

I connected the wires in the correct way and i used the code you can find on the page above, but it doesn't works!

  1. I correctly soldered all the wires (checked with multimeter);
  2. I used the correct diode and the correct resistor;
  3. When i upload the program and open the serial monitor, i can't see anything, even if with this program i should read "Ok" from the modem;
  4. I measured the output voltage of the modem: 3,4 volts, maybe is too low for the Arduino digital input?

.....who can help me? Maybe i have to amplify the output modem signal? If yes, in wich way? With an OpAmp?

Thanks for reading :slight_smile:

2

if you are using the hardware uart then you cant talk to the modem and the serial monitor at the same time. they use the same port. hook the modem up to some other pins and use newsoftserial to communicate to it, then use the hardware uart to send messages to the monitor.

3

Well, i don't know what is hardware uart :roll_eyes:...i'm using the newsoftserial library, using pin 2 and 3, is there any connection between the two things?
However, what do you think about the modem output voltage: 3,4 volts.....do you think Arduino can read it as a HIGH signal?

4

Well, i amplified the modem rx signal from 3.3 to 5 volts...but it doesn't work again! Any suggestion?