XBee Interface Board

The pins on the XBee radio (Digikey XB24-AWI-001-ND) have a pitch of 2 mm, which makes it impossible to plug into a standard 0.1 inch pitch breadboard. The XBee Interface Board allows one to plug the XBee into a breadboard or directly into a FTDI USB-RS232 cable.

The board can be:

• plugged flat into a breadboard
• plugged vertically into a breadboard
• plugged into an FTDI USB to RS232 converter cable

Of course, you can also solder wires directly to the board instead of using header pins.

Traxmaker Source Files and Gerber Files

The Traxmaker source files and Gerber files can be downloaded here:

Media:XBee_Interface_Board_Traxmaker_Gerber.zip

Media:XBee_Interface_Board_Traxmaker_Gerber_array.zip You can order an array of boards and cut them yourself.

PCB

PCB Schematic

The PCB

This is the PCB. If the PCB has fibers sticking out of the edge, scrape or file them off. These are glass fibers, and can stick into your finger like a splinter.

Components

Not all of the components are required. The voltage regulator and capacitor go together; if you don't need the regulator (if you already have a 3.3V supply), you won't need the capacitor either. The same goes for the LED and resistor.

1. 1. PCB
   2. 2x 10 pos. 2 mm pitch socket (Digikey S5751-10-ND)
   3. 2x 10 pos. header pin (broken off Digikey S1011E-36-ND)
   4. low current LED (Digikey 160-1086-ND)
   5. 6 pos. 90 degree header pin (broken off Digikey S1111E-36-ND)
   6. 1k resistor
   7. LE-33 low dropout voltage regulator (Digikey 497-4258-1-ND)
   8. 2.2uF tantalum capacitor (Digikey 399-3536-ND)

Populating the Board

2mm Socket

Make sure the sockets go in straight. If they are crooked, the XBee radio will not be able to plug in. Using tape to hold the socket in place while soldering may make it easier to solder.

Bad

Good

Voltage Regulator and Capacitor

The low-dropout voltage regulator will take any voltage 3.5V and higher and bring it down to 3.3V so the radio won't get fried. If you already have a 3.3V source, you can leave out the regulator and capacitor, and hook the power to the 'Out' pad where the voltage regulator would have been placed.

The 'out' pad is on the left

The capacitor is required for the low-dropout voltage regulator to be stable. Tantalum or electrolytic capacitors are best. Ceramic capacitors happen to work with the LE-33 regulator, but may not work with other low-dropout regulators.

Tantalum capacitors are polarized, so note the polarization. The positive terminal will have a small '+' sign on the package.

Note the polarity

LED

The LED illuminates when the board is powered. It won't hurt to leave it out if it isn't needed. The 1k resistor is just there to limit the current going through the LED, so if LED is left out, the 1k resistor should be left out too.

The LED is polarized. LEDs generally have a flat side which indicates the ground; the flat side corresponds to the side with the line (as opposed to the triangle) on the board's legend

Note the flat side on the LED

6 pos. 90 Degree Header

The 90 degree header allows the board to be plugged into a breadboard vertically or plugged into an FTDI USB-RS232 cable.

Interface board with 90 degree header

Plugged vertically into breadboard

Plugged into FTDI cable. Note the polarity of the cable; black is on the left and matches up with the small 'BLK' printed on the board.

10 pos. Straight Headers

Putting header pins on the interface board allows it to be plugged into a breadboard like a DIP package. The pins should be soldered from the top.

Interface board with straight headers

Solder from the top

Plugged into breadboard (the pins are still unsoldered in this photograph)