Arduino the journey continues

Transcription

1 Arduino the journey continues Mark Patrick, Mouser Electronics

2 The beginnings of Arduino The electronics industry is no stranger to innovation. There are probably hundreds of new products launched every day some are iterative releases of product lines already in production, while others announce a completely new technology. Their success, as with any product, tends to depend on a complex mix of market needs, timeliness and luck. When the open-source microcontroller-based development platform Arduino launched in 2005, there was certainly a market need, and the timing couldn t have been better. Figure 1: One of the early Arduino boards, the Arduino Duemilanove. (Source Arduino.cc) The design of the first 8-bit Arduino board came out of the need to create a simple, complete, plug-and-play microcontroller board on which students at the Ivrea Interaction Design Institute in Italy could base their product prototypes without needing a background in electronics. Arduino was certainly not the first microcontroller development platform; many others were already commercially available, but they did not offer the completeness of features or simplicity of design. Arduino not only provided the hardware prototyping platform, but also included a comprehensive integrated software development environment to create and program the board s microcontroller. Arduino s software development tools, available for Microsoft Windows, Apple OS X and Linux, were assembled from trusted products

3 that were already in use these being Wiring, used as the Arduino s programming language, while the IDE itself is based on Processing. Key to Arduino s success has been the seamless way in which both hardware and software have been tightly integrated. Figure 2: The comprehensive Arduino IDE. (Source Mouser)

4 Arduino s broad appeal Arduino has a very broad appeal from learning the basics of how to program a microcontroller to blink an LED on and off, to more sophisticated projects used to control scientific instruments in a chemistry lab. Teachers and students embrace it, musicians and artists bring their ideas to life with it, and architects build interactive models with it. There was clearly a need when Arduino launched, but its success is also partly due to the timing of the launch. The Maker community, a global unstructured collective of hobbyists and DIY electronics enthusiasts with opensource concepts at its roots, was just starting to form. Over the years interest in playing with electronics as a hobby had waned. Arduino filled a void, and was immediately accessible and affordable to those who wanted to tinker, play and learn. Continued evolution As interest in Arduino has grown, so has the range of boards available. The original 8-bit Atmel AVR (now Microchip) based design is still available as the Arduino Uno, but there are now more powerful boards such as the specialist FPGA-based Arduino MKR Vidor Another factor that has contributed to Arduino s success is that from the start it was open source, so the PCB design and schematics were all readily available under Creative Commons licence. Companies such as Adafruit have developed their own versions of the board, but have used the Arduino IDE for design simplicity and familiarity. From the beginning Arduino established a standard pin-out configuration to enable interaction with the real world. That format has spawned an industry of its own, creating expansion boards, termed shields, which plug into Arduino and third-party Arduino-compatible boards. Established electronics component manufacturing companies have also embraced the popularity of Arduino by developing their own shields as prototyping boards for their range of devices, be they sensors, MEMS devices or wireless communications chips. This approach saves the manufacturer significant NRE costs associated with developing and maintaining a custom evaluation board and makes the design accessible to anyone with an Arduino. An example is the multi-sensor development platform from Azoteq.

5 Figure 3: Collection of Arduino boards. (Source Arduino.cc) The latest Arduino boards Provisioning communications continues to be an essential element of any design. In the cloud-connected era of the Internet of Things (IoT) and its industrial counterpart (IIoT), communications is at the very core of an end-design. There are a wide variety of data communications protocols available, from power-hungry short-range WiFi that is ideal for sending large volumes of data, to the ultra-low-power long-range Sigfox and LoRa methods that suit sending small and infrequent data packets. As applications become more complex and sophisticated, the need to ease communications, provide management of the board s environment and run concurrent tasks has led Arduino to launch a platform that uses the open-source Linux operating system. Already used on the popular Raspberry Pi and BeagleBone Black single-board computers, the Arduino Yún, initially introduced in 2013 and integrating an Atmel AVR microcontroller with an Atheros AR9331 Linux wireless SoC, has recently received a major refresh of features and capabilities.

6 Arduino now offers a comprehensive line-up of single-board computers that covers the complete range of current data communication methods, including the 2.4 GHzbased methods WiFi and Bluetooth Low Energy, the 400 MHz and 900 MHz industrial, scientific and medical (ISM) spectrum using LoRa and Sigfox, and licensed cellular systems GSM and LTE. Arduino MKR WIFI 1010 The Arduino MKR WIFI 1010 is the latest Arduino board to support WiFi communication. Packaged in the standard MKR board/header format, and measuring 61.5 mm x 25 mm, the board integrates a Microchip SAMD21 Cortex- M0+ 32-bit low-power ARM microcontroller, a u-blox NINA-W102 Espressif dual-core ESP32-based 2.4 GHz wireless module with integrated antenna capable of WiFi b/g/n and dual-mode Bluetooth v4.2, and a Microchip ATECC508 SHA-256 cryptographic authentication IC. The ATECC508 offloads cryptographic tasks from the main CPU, such as those used to secure network communications via TLS. An onboard khz real-time clock (RTC) provides the 48 MHz processor clock. The MKR WIFI 1010 with its Cortex-M0+ MCU and the NINA-W102 offers a number of power-saving modes and features, providing an ideal prototyping platform for WiFi-based battery-powered IoT/IIoT applications. The wireless module can be switched off completely when not required, and also features a number of low-power modes that assist in balancing power output and data rate for optimal power consumption For low to medium production volumes the complete board could also be embedded into the design.

7 Figure 4: Arduino MKR WIFI (Source Arduino) The board can be powered directly from its 5 VDC USB port or via a single rechargeable Li-Po 3.7 VDC cell. A Li-Po charging circuit is provided, allowing battery charging when connected to an external power source. Switching between power sources takes place automatically. A total of eight digital GPIO pins can be configured as input or output within software, and there are twelve pins capable of supporting pulse width modulation (PWM) outputs. Serial communication options include one each of UART, SPI, I 2 C and I 2 S. There are a total of seven analogue input pins for use with a switchable 8-, 10- or 12- bit ADC, and one 10-bit analogue output pin. A total of six user LEDs are provided, and the MKR WIFI 1010 has 256 kb of Flash and 32 kb of SRAM. As with all Arduino platforms, comprehensive getting started instructions, device drivers and libraries are accessible via the Arduino IDE. Also, board-specific examples are automatically included when you add the MKR WIFI 1010 board support package to your Arduino IDE using the Board Manager. Arduino MKR WAN 1300 The Arduino MKR WAN 1300 is one of two Arduino boards that have been designed specifically to prototype low-power, long-range communication in the ISM 400 MHz,

8 800 MHz and 900 MHz spectrum. The MKR WAN 1300 uses the LoRa low-power wide-area network (LPWAN) protocol for sending relatively small amounts of data across an extremely wide area. Using a chirp spread spectrum approach in a star network architecture, a single LoRa gateway can cover a whole city or an area of several hundred square kilometres. Within Europe, the 867 to 869 MHz spectrum is reserved for ISM communications, a total of ten channels being available for LoRaWAN devices. Eight of these channels can use data rates from 250 bps up to 5.5 kbps, also, there is a single 11 kbps channel and a single-frequency shift-keying channel of 50 kbps. Output power is limited to +14 dbm. LoRa is aimed at IoT/IIoT sensors, utility meters and actuator applications which are battery operated with a multi-year lifetime, and securely send small amounts of encrypted data over long distances (over 10 km) a few times per hour. Figure 5: Arduino MKR WAN 1300 for prototyping LoRa applications. Using the Arduino standard MKR board format, measuring 67.5 mm x 25 mm and weighing only 32 grams, the MKR WAN 1300 comprises a Microchip SAMD1 ARM Cortex-M0+ 32-bit low-power microcontroller and a Murata CMWX1ZZABZ LoRa module. The MKR WAN 1300 has the same peripheral features as the MKR WIFI In addition to downloading libraries for the board, the Arduino website has a number of tutorials that showcase connecting to, sending and receiving data over the LoRa network. Prior to doing this you need to set up an account with a LoRa network provider, of which Arduino provides a tutorial to connect the MKR WAN 1300 to The Things Network (TTN).

9 Arduino MKR FOX 1200 Similar to the MKR WAN 1300 but using the Sigfox network is the Arduino MKR FOX Like LoRa, Sigfox is a lightweight protocol designed to handle small amounts of data, conserving energy consumption and prolonging battery life. Sigfox has relatively low transfer rates of either 100 or 600 bps, and an uplink payload of 12 bytes and downlink payload of 8 bytes. Figure 6: Arduino MKR FOX 1200 Sigfox board. Included with each MKR FOX 1200 is a free one-year Sigfox subscription that allows up to 140 messages per day in addition to free access to the geo-location service Spot it. This service allows you to track the board without the need for a GNSS/GPS receiver. The board s location is determined using a signal strength probability model when the transmit signals are received at multiple points of the Sigfox infrastructure. The MKR FOX 1200 has the standard MKR functionality and uses a Microchip ATA8520 Sigfox module. Several tutorials are available that showcase the steps involved in connecting the board to the Sigfox network and sending data. Arduino MKR GSM 1400 When it comes to sending larger amounts of data and provisioning a communications method that is usable globally without any reconfiguration or

10 regional subscriptions, the cellular GSM network is probably the only alternative. The new Arduino MKR GSM 1400 is capable of working on all global 3G cellular networks including GSM on 850 MHz, E-GSM on 1900 MHz, DCS on 1800 MHz and PCS on 1900 MHz. The MKR GSM 1400 integrates a Microchip SAMD21 device, the same as other Arduino MKR boards, and a u-blox SARA-U201 GSM module. Figure 7: The Arduino MKR GSM 1400 makes it simple to connect to the cellular network. The board makes it extremely straightforward to provision cellular communication to an application with the minimum of configuration. The Arduino website has a number of example programs that show how to connect to the cellular network, and send and receive data. Tutorials cover creating a web client to access a website page, and how to send an SMS text. Arduino MKR NB-1500 Providing support for one of the most recent low-power network standards, Narrowband IoT, is the Arduino MKR NB Using the established cellular network, the LTE 3GPP release 13, termed LTE Cat NB1 (NB-IoT) provides a peak downlink rate of 250 kbps. Such speeds are significantly higher than the ISM protocols LoRa and Sigfox yet NB-IoT offers a low-cost, long battery-life data communication approach. Also, compared to traditional cellular connectivity, the wake-up and connection times are much faster, ensuring that power consumption is

11 kept to a minimum. The MKR NB-1500 is designed for global use with leading cellular providers such as Vodafone AT&T, T-Mobile and Verizon and, using LTE Cat M1 and NB1 bands, the board is ideal for use in a wide variety of applications deployed in remote locations. Figure 8: The Arduino adds Narrowband IoT connectivity with the MKR NB The MKR NB-1500 offers all of the standard microcontroller and peripherals of an Arduino MKR board and uses a SARA R401 NB-IoT wireless module from u-blox. Arduino Yún Rev 2 The final board we review in this article is the Arduino Yún Rev 2. Combining both a Microchip ATMega32U4 AVR microcontroller and an Atheros AR9331 MIPS architecture microprocessor, the Yún marries the best of Arduino s ease of hardware interfacing with the trusted open-source and flexible Linux operating system. Operating from a single 5 V USB supply, the board s ATMega32U4 runs at 16 MHz and has a total of twenty available GPIO pins, seven of which can be used for PWM applications. 32 kb of onboard Flash is available, 4 kb of which is reserved for the board s bootloader.

12 Figure 9: The Arduino Yún Rev 2 combines traditional Arduino hardware flexibility with the open-source Linux operating system. The Atheros AR9331 is clocked at 400 MHz, has 64 MB DDR2 RAM and 16 MB of Flash. The board also features a 2.4 GHz b/g/n WiFi radio and an /100 Mbps Ethernet port, both of which connect to the Atheros processor. A microsd card socket is also connected to the Linux processor. An embedded OpenWrt Linux distribution is preloaded on the board, which includes a complete Python 2.7 installation.

13 Figure 10: Communication between the ATMega32U4 and the Atheros AR9331 is facilitated by the Arduino Bridge Library. Communication between the Arduino and the OpenWrt Linux is facilitated through a Bridge Library see Figure 10 full details of which, together with application examples, can be found on the Arduino website. A web-based software control panel permits configuration of the Linux environment together with the WiFi parameters. Access to the OpenWrt can also be made via the command line or via the secure shell, SSH. These new Arduino boards open up the capability for prototyping a host of IoT/IIoT applications using a variety of different networking protocols to suit your specific communication requirements. Whether you are designing a network of sensors that need to be deployed around a city, or need to control an item of industrial equipment in a remote location, there is an Arduino board that will fit your needs. Mouser Electronics Authorised Distributor

14 Mark Patrick Mark joined Mouser Electronics in July 2014 having previously held senior marketing roles at RS Components. Prior to RS, Mark spent 8 years at Texas Instruments in Applications Support and Technical Sales roles and holds a first class Honours Degree in Electronic Engineering from Coventry University.