Deploy a secure Cloud-connected IoT device network complete with Edge computing capabilities
Edge computing devices needs to be built and deployed. Software needs to be written to implement secure communications within the local network of IoT endpoints and Edge devices, as well as with Cloud services. Finally, those devices need to be appropriately configured, provisioned with suitable private keys and certifications, and authenticated with each other and the IoT Cloud service. To simplify the process, a set of Microchip boards provide AWS- qualified drop-in solutions for both endpoint and Edge devices able to connect simply and securely to the AWS Greengrass Core locally, and to the AWS IoT Core in the Cloud. Cloud-ready endpoint systems Designed for rapid deployment as endpoint systems, Microchip’s PIC-IoT WA and AVR-IoT WA boards are designed to provide out-of-the-box connectivity with AWS IoT Core. The two boards offer the same overall functionality but are designed to provide familiar platforms for developers accustomed to working with the Microchip PIC microcontroller family, and to those working with the Microchip AVR ATmega microcontroller family. Based on the Microchip ATMEGA4808 8-bit microcontroller, the AVR-IoT WA board uses the same set of components as the PIC-IoT WA
out-of-the-box support for AWS IoT authentication and security mechanisms. Using their collection of on-board hardware components and pre- loaded firmware, the boards are designed to connect with minimal effort to AWS IoT Core. Developers need only power up the board using a micro USB cable connected to their personal computer. After the board connects to a local Wi-Fi access point using its own credentials or the developer’s, it automatically establishes an MQTT connection with AWS IoT Core using the Wi-Fi module’s built-in TCP/IP stack and pre- provisioned security credentials. After establishing that MQTT connection, the board immediately begins transmitting data from its temperature and light sensors. Developers can view the results on a device-specific page in a Microchip sandbox account. Microchip provides this baseline application in separate repositories for PIC-IoT WA code and AVR- IoT WA code. By examining this code, developers can gain a quick understanding of the basic design patterns, such as the use of MQTT connections when communicating with the Cloud to send sensor data and to receive commands or data (Listing 1). Developers can extend this code using a variety of development resources. Microchip supports custom software development
Figure 4: The Microchip AVR-IoT WA and PIC-IoT WA boards provide Cloud-ready endpoint systems that include the same complement of support devices built around different Microchip microcontrollers, including a 16-bit PIC microcontroller for the PIC-IoT WA board shown here. Image source: Microchip Technology
Figure 3: Edge computing service architectures like AWS IoT Greengrass help maintain availability by providing shadow devices that can maintain the latest device state data, allowing IoT applications to continue to function even if the associated physical device goes offline. Image source: Amazon Web Services
and for enhanced availability. AWS Greengrass provides the foundation for delivering these capabilities. In the AWS Greengrass model, after a one-time discovery phase with Cloud services, endpoint devices within a defined Greengrass group interact with each other using MQ Telemetry Transport (MQTT) messaging managed by a Greengrass Core device (Figure 2). Once deployed in a Greengrass group, devices can cooperate to avoid lengthy roundtrip delays found in IoT deployments using IoT devices that communicate directly with the Cloud. Instead, devices can signal each other directly through MQTT channels mediated by the local processing capabilities of the Greengrass Core device.
If connectivity to the Cloud is lost, devices can continue to function under management of the Greengrass core device. Conversely, if a device goes offline, other devices and the Cloud- based application can continue to function using data maintained by a virtual device shadow associated with each physical device (Figure 3).
Besides a Microchip MCP9808 precision digital temperature sensor and a Vishay TEMT6000X01 photodiode sensor, each board includes a mikroBUS connector. Using this connector, developers can easily expand the hardware base by selecting add-on boards from the broad selection of available Mikroe Click boards. For power and battery management, the boards each include a Microchip MCP73871T-2CCI/ML device, which provides both system power and lithium-ion battery charging from a USB power source or wall adapter. For security, each board includes a Microchip ATECC608A secure element. For these boards, this device comes pre-provisioned with keys and certificates to provide
(Figure 4), which is based on the Microchip PIC24FJ128GA705 16-bit microcontroller. For connectivity, the boards each include a Microchip ATWINC1510- MR210PB certified Wi-Fi module designed specifically for low-power IoT devices. The module integrates 8 megabits (Mbits) of flash and a complete transmission and receiver radio frequency (RF) signal chain including power amplifier (PA), low- noise amplifier (LNA), RF switch, power management, and printed antenna. Along with integrated boot read-only memory (ROM) for rapid firmware boot capability, the built-in network stack supports standard Internet protocols using hardware accelerators to speed Transport Layer Security (TLS) and Wi-Fi security protocols.
Although straightforward in concept, implementing this
coordination among a set of IoT devices can be challenging. For a typical IoT developer, taking full advantage of this Edge computing capability presents a daunting combination of hardware, software, and systems administration challenges. At the hardware level, a network of suitable endpoint and
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