UnaShield Hardware Guide

Version v1.0


About the UnaShield


Pin Assignment

Features and Functions

Frequently Asked Questions

About the UnaShield

UnaShield is an Arduino Shield with a Sigfox transceiver module that is compatible with Arduino Uno R3 and other Arduino-based development boards. It uses Sigfox-certified WISOL or Radiocrafts modules to support all RCZs (Radio Configuration Zones).

Features   V1A (20161128) V2 (20170325) V2S (20170107) V2S (20170325) V2S2 (20181109)
Sigfox Module Radiocrafts RC1692HP-SIG        
  Sigfox RCZ 2 / 4 1 / 2 / 3 / 4 1 / 2 / 3 / 4 1 / 2 / 3 / 4 1 / 2 / 3 / 4
Sensor Accelerometer (MMA8451Q)      
  Accelerometer (LSM303AGR)        
  Temperature Sensor (BME280)    
  Humidity Sensor (BME280)    
  Pressure Sensor (BME280)    
  Push Button  
Peripheral Connection Digital Grove (I2C)  
  Analog Grove  
LED Power Indication
  General Indication  
  Module Status Monitor  
Antenna Matching Circuit    


(Click the image to enlarge)

【UnaShield V1A】

【UnaShield V2S】20170107

【UnaShield V2 / V2S】20170325

【UnaShield V2S2】20181109

Pin Assignment

Arduino Pins UnaShield V1A UnaShield V2 / V2S / V2S2 Description
Reserved NC NC Reserved
IOREF 5V 5V 5V Power Source from Arduino platform
RESET RESET RESET Reset Arduino MCU & Sigfox Module;Low active
3V3 3V3 3V3 3V3 Power Source from Arduino platform
5V 5V 5V 5V Power Source from Arduino platform
GND GND GND Grounding & power/signal reference level
GND GND GND Grounding & power/signal reference level
VIN NC NC Extra power source input of Arduino platform
A0 NC NC Analog Pin-0
A1 NC NC Analog Pin-1
A2 NC A2 Analog Pin-2;Grove Connector #2
A3 NC A3 Analog Pin-3;Grove Connector #2
A4 NC I2C-SDA Analog Pin-4;Grove Connector #1
A5 NC I2C-SCL Analog Pin-5;Grove Connector #1
SCL NC NC Branch of A5 (I2C-SCL)
SDA NC NC Branch of A4 (I2C-SDA)
AREF NC NC Reference level input for Arduino MCU
GND GND GND Grounding & power/signal reference level
D13 NC NC Digital Pin-13
D12 NC NC Digital Pin-12
D11 NC NC Digital Pin-11
D10 NC NC Digital Pin-10
D9 NC Red-LED User Programmable Red LED
D8 NC Green-LED User Programmable Green LED
D7 NC Wakeup Wakeup onboard module from deep sleep mode
D6 NC Button Push button;Push to low signal level
D5 UART-RX UART-RX UART receiving pin
D4 UART-TX UART-TX UART transmitting pin
D3 NC INT2 Interrupt#2 of Accelerometer INT2 (V2S2: Select by J205)
D2 NC INT1 Interrupt#1 of Accelerometer INT1
D1 NC NC Digital Pin-1
D0 NC NC Digital Pin-0

Features and Functions

1. SMA Connector

The SMA (SubMiniature version A) Connector is used for connecting the provided coaxial RF antenna to the UnaShield.

To prevent damage to the onboard Sigfox module, always connect the antenna before powering up the UnaShield and before sending any Sigfox messages.

2. Sigfox Module

UnaShield V1(A) embeds a Radiocrafts Sigfox module RC1692HP-SIG, certified for RCZ2 and RCZ4; UnaShield V2 / V2S uses a WISOL Sigfox module in the WSSFM10R Series, certified for all four RCZs. The Sigfox modules may be controlled via the UART interface with serial terminal commands (similar to the AT Command Format used by modems).

UnaShield V1A UnaShield V2 / V2S / V2S2
Radiocrafts RC1692HP-SIG WISOL WSSFM10R
For RCZ2 and 4 For all RCZs: RCZ1, 2, 3 and 4

3. Arduino Uno Standard Header

UnaShield has four Arduino standard headers (pin connectors): one 6-pin header, two 8-pin headers, and one 10-pin header. Not all Arduino pins are used by the UnaShield, some Arduino pins are passed through unmodified by UnaShield.

You may use the unused Arduino pins to connect other sensors and components. However take note that the voltage level of Arduino Uno R3 is 5V, which may not be directly usable by some sensors or components.

For the details of each Arduino Uno pin assignment and definition, please check the Arduino official website:


4. Push Button (UnaShield V2 / V2S / V2S2 only)

A Push Button (tact switch) is connected to the D6 Digital Input pin of the Arduino Uno.

The button may be programmed in Arduino sketches to trigger certain functions when pressed.

5. Grove Connector (UnaShield V2 / V2S / V2S2 only)

UnaShield V2S is equipped with two Grove Connectors, a standard 4-pin connector for Grove sensors. You may connect sensors or components with Grove interfaces to extend the capabilities of the Arduino device.

Grove Connector #1:Connected to Arduino I2C Digital Interface (SCL and SDA)

Grove Connector #2:Connected to Arduino Analog Input/Output interface (A2 and A3)

The onboard Grove connectors support two voltage levels: 3V3 or 5V. Select the Grove voltage through jumper J204.

  Floating 5V 3.3V (Default)
Jumper J204

6. LED Indicator and Manual Switches (UnaShield V2 / V2S only)

Eight onboard LEDs are used to show the status of the UnaShield. The LEDs may be disabled through the jumpers J201, J202 and J203.

Jumper J201 – Controls the Status LEDs of the WISOL module (TX, RX, CPU & RF)

  Disabled Enabled (Default)
Jumper J201

Jumper J202 – Controls the Grove Voltage Level LED (3V3 or 5V)

  Disabled Enabled (Default)
Jumper J202

Jumper J203 – Controls the User-Programmable LEDs (D8, D9)

  Disabled Enabled (Default)
Jumper J203

7. I2C Interface (UnaShield V2 / V2S only)

I2C (Inter-Integrated Circuit) is a two-wire, bidirectional protocol for connecting multiple sensors and components on the same pair of wires.

The I2C interface requires two pins: data line (SDA) and clock line (SCK). I2C works in the daisy-chain configuration, so one master device can communicate with more than one slave device, just by selecting the unique I2C address of the slave device.

The UnaShield accelerometer sensor and temperature / humidity / pressure sensor are connected to the I2C bus by unique I2C addresses, which are preset in the sensor hardware.

NXP Accelerometer (G-Sensor) – MMA8451Q

SA0 I2C Address Default
LOW 0x1C
HIGH 0x1D  

ST Accelerometer (G-Sensor) – LSM303AGR

Function I2C Address Default
Accelerometer 0x32
Magnet 0x3C

BOSCH Temperature / Humidity / Pressure Sensor – BME280

SD0 I2C Address Default
LOW 0x76
HIGH 0x77  

Grove Connector #1

Grove Connector #1 is also connected to the I2C bus. The sensor or component connected through Grove Connector #1 must use an I2C address that is distinct from the above I2C addresses, to avoid address conflict.

8. INT selector (UnaShield V2S2 only)

Select UnaShield V2S2 onboard G-Sensor interrupt signal from accelerometer interrupt 2 or magnet sensor interrupt.

Jumper J205 - Select onboard G-Sensor Interrupt signal.

Jumper Floating Magnet Interrupt Accelerometer Interrupt

Frequently Asked Questions

Can the UnaShield be used on all Arduino boards?

UnaShield has been thoroughly tested on Arduino Uno R3. However it’s not compatible with all variants of Arduino boards, due to the different pin definitions. Here two classes of Arduino boards that are incompatible with the UnaShield due to the pin definitions:

Arduino Mega / Mega2560: Only the following pins are supported for UART RX in Mega & Mega2560:

Arduino Leonardo / Micro: Only the following pins are supported for UART RX in Leonardo & Micro:

If you are using one of these Arduino boards, perform the two steps below to switch the UnaShield’s UART Receiving Pin (UART-RX) from Arduino D5 Pin to another Arduino pin with UART RX capability.

Note that Arduino D5, D6 Pins are High Impedence (HI-Z). The replacement pins should also be HI-Z pins, as indicated in the table below.

Step 1

Assign the original UnaShield Pin 5 (UART-RX) as an input, by choosing a setting marked Green in the table below. You may keep UnaShield Pin 5 (UART-RX) disconnected on the Arduino Uno R3.

Step 2

Connect UnaShield Pin 5 (UART-RX) to one of the Arduino pins below with UART receiving capability, so that it becomes the new UART-RX. Use a jumper cable to connect the pins.

DDxn PORTxn PUD (in MCUCR) I/O Pull-Up Comment
0 1 0 INPUT YES  
1 0 X OUTPUT NO Output Low
1 1 X OUTPUT NO Output High

Can UnaShield work as a breakout board?

UnaShield can be the breakout board of the onboard Sigfox module. Only five pins need to connected, so that the Sigfox module can be controlled by any external MCU (e.g. ARM CPU, Raspberry Pi) or integrated to any existing system.

Power Pins: UART Interface:
- 3V3 - UART-TX (D4)
- 5V - UART-RX (D5)
- GND  

Both 3V3 and 5V UART signaling levels are accepted. The UnaShield’s level-shifting circuit regulates the 5V UART signaling to 3V3, which is the nominal power level of the onboard Sigfox module.

Can the UART Interface be reused?

The Arduino D4, D5 pins are used by the UART interface on UnaShield, for communicating with the onboard Sigfox module.

UART communications is designed for two endpoints only, so D4, D5 cannot be connected for any other purpose.

Can the I2C Interface be reused?

The Arduino A4, A5 pins are used by the I2C interface on UnaShield, connected to he UnaShield accelerometer sensor, temperature / humidity / pressure sensor and Grove Connector #1.

The I2C interface works in daisy-chain mode. Each terminal should have a unique I2C address so that they may be connected serially. Every message transmitted on I2C contains the unique I2C address of the receiver, so that only one of the terminals in the daisy-chain can intercept and process the message.

Any I2C device with a unique and distinguishable address can connect to these two pins simultaneously.

Can Grove Connector #2 (A2, A3) be reused?

The A2, A3 pins are connected to Grove Connector #2 and to Grove sensor connected to that port. If Grove Connector #2 is not connected to any Grove sensor, then A2, A3 can be used for other Analog Input/Output connections.

Can Arduino Pins D8, D9 be reused?

The D8 & D9 pins control the User-Programmable LED. Remove jumper J203 to disable the LED function, then D8, D9 may be reused for other Digital Input/Output connections.

What’s the guideline for deciding if a pin is reusable?

Each pin can only be assigned to one function. The pin may not be reused until the default function of that pin has been deactivated. If the same pin is used by two circuits (e.g. UART Interface and Digital Input/Output), the conflict in the electrical signalling will lead to failure of both functions.

The only exception is the I2C connection, which supports daisy-chaining of multiple sensors on the same two I2C pins.

What are the limitations of the Arduino Input/Output pins?

UnaShield was designed for the Arduino hardware platform. All the Arduino Input/Output pins derive from the Arduino MCU. Maximal current for each I/O pin is 40mA on Arduino Uno R3.

How do I activate the UnaShield?

Follow the steps here to activate your UnaShield:


Each UnaShield activated will enjoy one year of free Sigfox subscription.

What is the warranty for UnaShield?

The UnaShield is covered by a 3-month warranty, one-for-one exchange. Proof of purchase must be produced upon exchange.

UnaShield Developer’s Guide

The UnaShield Arduino library and sample codes for the may be downloaded at


Getting the UnaShield

To order the UnaShield, please contact UnaBiz:


Ms. Kimberley Thong

Business Development Manager


Taiwan and Rest of the World

Mr. Nicolas Baele

Global Account Manager