Integral Design

The drivers for the Cellular Radio module from Seeed Studio are still in development, so any code using this module has to be tentative at this stage. << Note: the new driver  by Eduardo Velloso has now been released: Drivers for the .NET Gadgeteer Cellular Radio Module.>> That said, using the module for voice calling requires only a little information about AT command syntax.  Any SIM card with a phone account will work in the card slot.

You’ll need a microphone/speaker set that has separate plugs for mic and speaker.  I found an old headset from a language instruction software kit that works.  The GHI Electronics Fez Spider Mainboard works fine with the Seeed Cellular Radio module.

The following video shows all the components.

Other than the hardware all you need to start calling is the following code.

using Microsoft.SPOT;
using Gadgeteer.Modules.GHIElectronics;

namespace SeeedCellularRadio
{
    public partial class Program
    {
        void ProgramStarted()
        {
            cellularRadio.PowerOn();
            button.ButtonPressed += new Button.ButtonEventHandler(button_ButtonPressed);
            Debug.Print("Program Started");
        }

        void button_ButtonPressed(Button sender, Button.ButtonState state)
        {
            if (button.IsLedOn)
            {
                cellularRadio.SendATCommand("H"); // Hang up voice call.
                button.TurnLEDOff();
            }
            else
            {
                // Dial voice call; Use phone number as string without hyphens.
                cellularRadio.SendATCommand("D2065780941;");
                button.TurnLEDOn();
            }
        }
    }
}

You can send a text message with the current beta driver, but until a driver is released with access to the serial line, you won’t be able to receive text or see what is going on with the AT Commands.