If we’re to build a massively scalable internet of things, we’re going to need tools that can handle hundreds of thousands of devices and a massive throughput of data. That’s hard to deliver with on-premises systems, but one that’s eminently suited to the scale and scalability of the public cloud.
While there’s a Windows for IoT hardware, the heart of Microsoft’s IoT platform is its Azure cloud, with a suite of tools and services that can build massive scale industrial IoT applications. One key element of that suite is IoT Hub, a routing service that sits between your devices and gateways and your back-end cloud services.
Inside Azure IoT Hub
Azure IoT Hub manages messaging connections to and from your devices, either directly for devices with IP connectivity or via gateways for hardware that uses proprietary or low-power protocols. It sits in Azure, behind edge computing services, providing a management layer and the ability to ingest significant amounts of data from a large number of connected devices.
Microsoft markets it as a key component of an industrial IoT platform, supporting the applications, services, and hardware that go into automating industrial applications, whether on a single site or distributed around the world. Connections are secure, and you can provide declarative rules to route messages to specific applications and services running on Azure. There’s a close relationship between IoT Hub and Event Grid: messages routed by IoT Hub are a source of events for Event Grid’s publish and subscribe service.
The result is a useful tool, but it’s overkill for many IoT scenarios because of the overhead of its built-in management tool. Although complex devices need support for high-level management tools and the ability to reconfigure applications on the fly, many IoT devices are very simple microcontrollers with limited storage, where applications are loaded as firmware.
Introducing the IoT Huh Basic service tier
That’s led to Microsoft’s recent launch of the new Basic service tier for IoT Hub, designed to support simpler devices, working only with device-to-cloud connections.
Much of Azure IoT Hub’s message routing functionality is available in the new Basic tier. However, many management functions have been dropped because they’re not needed by microcontrollers. For example, you can’t use it to configure or update your devices, so there’s no cloud-to-device messaging or support for complex management techniques like digital twins. If you’re deploying hardware only to deliver telemetry to a management application, that shouldn’t be a problem; you’re using microcontroller-based IoT hardware to integrate with existing sensors or adding new sensors to a process.
With a proliferation of low-end IoT chipsets built around wireless communications, and with low-cost cellular connections specifically targetted at IoT scenarios, it’s clear that telemetry is a key scenario for industrial IoT applications. Microsoft’s own Azure IoT Starter Kit is a Wi-Fi-connected sensor board, ideal for building your first IoT Hub application. Arduino-style devices like this are easy to program, easy to deploy, and cheap enough to treat as disposable. If you need to deploy new code, program up a new device and swap it out. It’s likely to be as quick as deploying new firmware over a wireless connection.
If you drill into the available APIs, you’ll also see that there’s a significant difference in the capabilities IoT Hub Basic applications have for interacting with your devices. The Basic tier only offers tools for adding and removing devices, as well as handling incoming data. More complex device interactions need the Standard tier subscription, reinforcing Microsoft’s focus on Basic as a device-to-cloud platform.
For its focus on telemetry models, the IoT Hub Basic tier is significantly cheaper than the IoT Hub Standard tier. The price per unit per month for the Basic B1 version is $10 for 400,000 messages per day. If you’re looking at sending significant amounts of data, the B3 offering is a bargain: $500 a month for 300,000 messages a day for each connect device, versus $2,500 a month for the Standard tier.
For industrial telemetry, where you’re using devices to monitor production lines, that can be a significant boost to thin profit lines. Reducing the cost to these levels should also make implementing an industrial IoT program more attractive, letting you take advantage of machine learning-based predictive maintenance, as well as enhanced monitoring of production processes.
Although there’s no free option with the IoT Hub Basic tier, you can use the IoT Hub Standard free tier for prototyping. Once you go into production, you’ll switch to Basic, because the free Standard version gives you only 8,000 messages per day per unit.
Massive IoT deployments can be expensive, even when taking advantage of options like IoT Hub Basic. You can use the Standard free tier to understand what your options are, with a small number of small messages, before scaling up to a full-scale deployment, finally registering different devices on different plans as you gain a picture of message density and complexity. Azure lets you mix and match plans, so where you need a high-resolution view of an operation, you can place a handful of devices on IoT Hub Basic B3 subscriptions. Meanwhile, normal operations and lower-resolution measurements can deploy on IoT Hub Basic B1.
You can manage costs further up the stack by using IoT Hub to feed into Azure Event Grid and then into serverless Azure Functions. The resulting on-demand architecture treats messages from devices as events and processes them appropriately, working with pretrained machine learning models and with functions that handle alerts to implement an effective industrial control system for only a few hundred dollars a month of per-second Azure billings.