Designing intelligent sensors for use on the "Internet of Things" - Part 2

In general, custom hardware can run faster than microprocessor-driven systems, but usually at the price of increased production costs and limited flexibility. Microprocessors, while not necessarily as fast as a custom hardware solution, offer the great advantage of design flexibility and tend to be lower-priced since they can be applied to a variety of situations rather than a single application.

Once we have on-board intelligence, we’re able to solve several of the problems that we noted earlier. Calibration can be automated, component drift can be virtually eliminated through the use of purely mathematical processing algorithms, and we can compensate for environmental changes by monitoring conditions on a periodic basis and making the appropriate adjustments automatically. Adding a brain makes the designer’s life much easier.

A relatively new class of microprocessor, known as a digital signal controller or DSC, is rapidly finding favor in products that require low cost, a high degree of integration, and the ability to run both branch-intensive and computationally intensive software efficiently.

Although usually not as fast as custom digital hardware, in many cases DSCs are fast enough to implement the necessary algorithms. At the end of the day, that’s all that really matters.

Finish Up with Quick and Reliable Communications
That leaves just one unresolved issue: sharing sensor values so systems that have to share sensor outputs can scale easily. Once again, the fact that the sensor data is numeric allows us to meet this requirement reliably.

Just as sharing information adds to its value in the human world, so too the sharing of measurements with other components within the system or with other systems adds to the value of these measurements. To do this, we need to equip our intelligent sensor with a standardized means to communicate its information to other elements.

By using standardized methods of communication, we ensure that the sensor’s information can be shared as broadly, as easily, and as reliably as possible, thus maximizing the usefulness of the sensor and the information it produces.

Put It All Together, and You’ve Got an Intelligent Sensor
At this point, we’ve outlined the three characteristics that most engineers consider to be mandatory for an intelligent sensor (sometimes called a smart sensor):

1. a sensing element that measures one or more physical parameters (essentially the traditional sensor we’ve been discussing),

2. a computational element that analyzes the measurements made by the sensing element, and

3. a communication interface to the outside world that allows the device to exchange information with other components in a larger system.

It’s the last two elements that really distinguish intelligent sensors from their more common standard sensor relatives (Figure 1.3 below), because they provide the abilities to turn data directly into information, to use that information locally, and to communicate it to other elements in the system.

Figure 1.3. Block diagram of a standard sensor (above) and an intelligent sensor (below)

Essentially, intelligent sensors “flatten” the sensor world, allowing sensors to connect to other sensors nearby or around the globe and to accomplish tasks that simply weren’t possible prior to their development.

Just as importantly, because so much of their functionality comes from the software that controls them, companies can differentiate their products merely by changing the configuration of the software that runs in them.

This has two very important consequences for suppliers of intelligent sensors. First, it essentially moves the supplier from a hardware-based product to a soft-ware-based product.

While it’s certainly true that there has to be a basic hardware platform for the sensor (this is, after all, a physical device), the hardware is no longer the primary vehicle for adding (or capturing) value; the software that controls the intelligent sensor is.

Because the manufacturer can add or delete features by flipping a configuration bit in software, it can alter its product mix almost instantaneously, and the specific product configuration doesn’t have to be finalized until just before final test and shipment.

One hardware platform can be used on multiple products targeted for different market segments at different price points; and, once new features have been developed, no additional production costs are required in order to include them in the product, so marginal profit soars.

The second consequence is that, because the intelligent sensor is connected to the outside world, the supplier now has the ability to gather information on the operation of its sensors in the field under real-world conditions and to update the software running the sensors after they leave the factory.

Not only does the information from the field offer the sensor manufacturer unparalleled insight into the needs and concerns of its customers, but it also provides the hard data required to determine the issues that are most important to those customers (and hence are the ones that the customers are most likely to value).

Armed with this information, sensor manufacturers can quickly add new features, offer certain configurations on an as-needed basis, or perform maintenance, all without having to touch the sensor itself. Services can now be delivered cost-effectively from central locations, providing yet another opportunity for the supplier to capture additional value and profits. An example of this is reported in the Harvard Business Review:

Most manufacturers cannot charge more than $90 to $110 per hour for their technical support because of price and benefit pressures from local competitors. But GE Energy, because of its efficient network-enabled remote servicing, can charge $500 to $600 per hour for the same technician.

Even more important, the information generated by its continual monitoring allows GE to take on additional tasks, such as managing a customer’s spare parts inventory or providing the customer’s and GE’s service and support personnel with complete access to unified data and knowledge about the status of the equipment.