XBee Stacker

The Stacker is an XBee radio-sized Arduino-compatible microcontroller that can be “stacked” directly underneath the radio. It is intended for use with devices that already use the XBee’s 20-pin footprint. Future designs could easily utilize other microcontrollers or host sensors.  The goal is to create plug-and-play tools for prototyping new concepts that extend the popular radio’s feature set. A few iterations have created a prototype that works well, supports USB programming, wireless programming, I2C, SPI, digital and analog I/O!

XBee Stacker 2

This is the next iteration of an Arduino-compatible board the size of an XBee that fits right underneath the radio. It uses the ATMega32U4 so in Arduino you can program it as a Leonardo board.

“XBee Stacker 2” Arduino/ATMEL board design 

IMG_2932 IMG_2934IMG_2930 IMG_2933


  • I2C

  • SPI

  • scriptable interruption of:

    • all UART transactions

    • XBee pin sleep controls

  • local support for:

    • association indicator

    • commissioning button

  • 17 total digital i/o pins (14 Arduino, 4 XBee)

    • 6 configurable as ADC analog inputs

    • 4 configurable as PWM analog outputs

    • 2 attachable interrupts

  • USB serial programming

  • wireless programming


  • multiple UARTs

  • Use of all Arduino libraries, e.g. servo, stepper, displays, capacitive sensing, rfid, sd cards etc.


Bottom of XBee Stacker 2:


Physical PinFunctionArduino Connection
1Power supplyVCC
2Arduino software TXD11 (softserial TX)
3Arduino software RX, PWMD10 (softserial RX)
4MISO (spi), digital i/oMISO (spi)
5input for Arduino resetRESET
6digital i/o, analog outputD9
7MOSI (spi), analog input, digital i/oMOSI (spi)
8analog input, digital i/oD8/A8
9PWM, interrupt, digital i/oD7
11SCK (spi), digital i/oSCK (spi)
12SDA (i2c) interrupt, digital i/oD2/SDA (i2c)
13SCL (i2c), interrupt, PWM, digital i/oD3/SCL (i2c)
14analog input, digital i/oD4/A6
15PWM, digital i/oD5 pwm
16analog input, PWM, digital i/oD6/A7 pwm
17analog input, digital i/oA3
18analog input, digital i/oA2
19analog input, digital i/oA1
20analog input, digital i/oA0

Top of XBee Stacker 2

XBee Stacker 2 top pins

XBee Physical Pin Function XBee Connection
1Power supplyVCC
2Arduino RXD0 RX
3Arduino TXD1 TX
5 -
9control for pin sleepD12
14voltage referenceVCC
15association output<led>
17Arduino Reset (p1) via cap.<capacitor> for reset
18 -
19 -

Schematics & Board Layout

XBee Stacker Arduino 2.0-board

XBee Stacker Arduino 2.0-schematic


Sample code library

Program as an Arduino Leonardo board!




Not determined, leaning toward open source hardware.

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