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 Pin Function Arduino Connection
1 Power supply VCC
2 Arduino software TX D11 (softserial TX)
3 Arduino software RX, PWM D10 (softserial RX)
4 MISO (spi), digital i/o MISO (spi)
5 input for Arduino reset RESET
6 digital i/o, analog output D9
7 MOSI (spi), analog input, digital i/o MOSI (spi)
8 analog input, digital i/o D8/A8
9 PWM, interrupt, digital i/o D7
11 SCK (spi), digital i/o SCK (spi)
12 SDA (i2c) interrupt, digital i/o D2/SDA (i2c)
13 SCL (i2c), interrupt, PWM, digital i/o D3/SCL (i2c)
14 analog input, digital i/o D4/A6
15 PWM, digital i/o D5 pwm
16 analog input, PWM, digital i/o D6/A7 pwm
17 analog input, digital i/o A3
18 analog input, digital i/o A2
19 analog input, digital i/o A1
20 analog input, digital i/o A0

Top of XBee Stacker 2

XBee Stacker 2 top pins

XBee Physical Pin  Function  XBee Connection
1 Power supply VCC
2 Arduino RX D0 RX
3 Arduino TX D1 TX
5  -
9 control for pin sleep D12
12 CTS A4
14 voltage reference VCC
15 association output <led>
16 RTS A5
17 Arduino 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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