The M590 module is a small and very compact module that is perfect for hiding away and providing feedback over SMS, or acting upon a phone call or text message containing a specific code.
The module power itself is 5v, but the logic over the Transmit and Receive lines are 3.3v. Although perfect for a similar logic device such as a Raspberry Pi, a logic leveller such as a MAX232 is required for 5v devices such as an Arduino.
If this is the first time soldering surface mount components, it is best to practice on some scrap parts, for more information on soldering read our Soldering Guide.
Magnifying Glass (depending on your eyesight)
The first component is a resistor that hides underneath the module, so would be the best one to start with. Locate R2, and apply a small amount of solder to one pad, pick up the resistor with the tweezers – as fingers are too big for these components – and reheat the same soldered pad whilst placing one side of the resistor in the solder. Finish up by soldering the other side.
Same process again for the diode, as you may notice the pad is just a little bit too small so in my case I soldered on a slight diagonal to ensure heat from the iron got to the pad. The diode must be soldered in a certain direction, the marked line on top of the diode must face the curved mark on the PCB.
Soldering components on the top
Flip the PCB over to add the resistor and LED. Looking closely at the LED, one side will have a green mark to indicate the Cathode – The negative side. With the PCB as shown, the green mark will be to the left away from the resistor. Again solder one pad and carefully place the LED on the heated solder, try to keep heat on the LED to a minimum as too much heat can damage the diode chip inside.
Follow up by adding solder to the other side, and proceed to solder the resistor on too, if too much solder is added to bridge the resistor and LED together, a solder sucker/pump can be used to remove it, although it isn’t crucial as the PCB joins them together.
Adding the SIM tray
Start by getting the orientation by following the corner triangle in the top right of the picture, and also ensure with the pads lined up that the tray fall within the rectangle.
Pick an easy to solder leg, such as the one closest to the triangle, and solder this one pin to hold the tray in place, as it is easier to adjust the alignment if required.
With a careful bend the tray can be properly lined up, and the rest of the pads soldered up.
Solder the module
Now for the biggest piece, the module itself. If the antenna is in the way, this can be carefully removed with a thumbnail. Place the module through the holes in the PCB with the antennae towards the diode, flip the whole thing over and solder the pins on the underside.
Adding the headers
Completely optional but for ease of prototyping, headers can be added to allow quick plugging in of jumper wires to a breadboard or micro controller of choice. The headers can be snipped with a pair of wire cutters in to a 6 pin header, and 2 single headers for power.
The headers can be held in place with blue tack to hold it in place.
The pins for the breakout board are as follows:
|+5v||5v power supply in|
|GND||Ground – 0v|
|I||Ring – Output (Will pulse low for an incoming call or SMS)|
|T||Transmit (3.3v logic)|
|R||Receive (3.3v logic)|
|V||Voltage after diode (Around 4.45v – M590 maximum is 4.5v)|
|K||On/Off (Latched input – Pull low to turn on, pull low again to turn module off)|
|G||Ground – 0v|