Nxp introduction to Iot components

Figure 1. 
The Anatomy of a Wireless Sensor Node
Source: Electronic Design
Consider commercial office environments and consider what a conference room thermostat needs to do: As important as it may seem for the comfort and productivity of the
conference room’s occupants, an environmental monitoring device — for temperature, humidity (air quality) and lighting — the thermostat/controller may need to take only a small
number of readings over the course of an hour, and make an even smaller number of adjustments. The reason is simple: Even unregulated, room temperatures will not change very
rapidly. (It will take the sensors several minutes to register a change.)
A ½-horsepower electric motor driving a conveyor belt in an automated factory, on the other hand, will need closer monitoring to produce the proper torque. The load on the
machinery could prove taxing, forcing the motor to generate more torque, consuming a lot of current in the process; its coils could groan and smoke.
Near Field Communications devices (NFC) can be used as sensors on an IoT node. In addition to processing transactions at point-of-sale (PoS) terminal, NFC devices can be used
as the front ends of IoT data-gathering nodes. Simply swiping an NFC card in the proximity of a card reader will release the turnstile at bus or train terminal, unlock a hotel room door,
or start the lights in your kitchen when you return home from work. From the point of view of the consumer, swiping low-energy card is simple and easy. But, used a sensor front end
to an IoT data gathering operation, NFC devices can track hotel occupancy rates, the use of public transportation, and residential energy consumption,
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Internet of Things (/wps/portal/apac/resources/articles/technologies/internet-of-things/)
Hardware (/wps/portal/apac/resources/articles/technologies/hardware/)

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But in each example, the task of the sensors, microcontrollers and communications circuitry is very much the same: The sensor will take a reading on the temperature produced by
the HVAC system (heating, ventilation, air conditioning), or the conveyor belt speed produced by the motor drivers attached to (say) an industrial programmable logic controller (PLC).
The signal conditioning circuitry will amplify (and, often, linearize) the output of the sensors so that it can be read by the microcontroller. (The sensor signal conditioning circuiting may
include an analog-to-digital converter, though increasingly it is on-chip with the microcontroller.)
The room environmental monitor or motor control may adjust in response. The communication portion of the IoT sensor node will likely leave a record of the transaction and/or use its
connection to the cloud computing resource to further analyze the data generated. The microcontroller may confirm that the value is correct, or suggest a corrective.
Microcontrollers architected around ARM processor cores, or the still-lively 8051, are among the most popular. Software development kits and firmware samples for a wide range of
these controllers are readily available. As a general rule, however, processor performance is dictated by clock speeds, bit-width and local memory — and higher performance
demands higher power consumption.
Regardless of what type of sensors are employed (ambient light, environmental temperature, motor speed, etc.), regardless of the processor bit-width of the microcontroller (8-, 16- or
32-bit), regardless of the communications loop (WiFi, ZigBee, or Blue Tooth), the sequence of collecting and evaluating data from a remote sensor loop remains mostly the same for
anything you put in service to the IoT.
A word about timing, or the sequence of events: No matter what the sensor node is used for, it will likely spend much of its time (as much as 95% of it, in fact) asleep. A change in the
sensor’s environment (movement, temperature, pressure, etc.) will bring the sensor to life. It, in turn, will wake the microcontroller, which asks, searching its memory for something
familiar, “What have we got here?”
Most of the time the answer will be something to the effect of “nothing to worry about.” The processor will inform whatever is attached to its communications port… and go back to
sleep. And that chain reaction will be much the same, regardless of whether you’re monitoring an industrial machine tool, slamming on your car’s ABS brakes, or checking on your
home’s security with a smart phone.
To be sure, the proliferation of sensor nodes will be dependent on a wide array of components and functions supporting the entire chain, from sensor to data stream. These additional
components (Analog and Connectivity) include:
Sensor Signal Conditioning
Power Management
Near Field Communications (NFC)
Sensor Signal Conditioning
In a large majority of IoT applications, there may be no separate signal conditioning semiconductors. The signal conditioning circuits are either integrated with the sensor module
package, or with the microcontrollers. Whether visible or not as a separate component, the signal conditioning is necessary to ensure the sensor can be understood by the node’s
microcontroller.
In motion detectors, one example, a MEMS device will require at least two levels of signal conditioning: one to bias the micro-electromechanical system, and amplify its output;
another to simplify its output (or make the sensor output easier for the microcontroller easier to interpret).
MEMS suppliers frequently will combine a signal conditioning ASIC — a “Sensor Fusion” DSP — in the same semiconductor package with the sensor element. The sensor fusion
element streamlines the output of the MEMS sensor so that the waveforms generated by the sensor are easier to interpret.
In modern smart phones, the in-package sensor fusion element will supplement other motion detectors, to serve as footstep counters and/or provide other location-based services
(like site-based ad servers) based on the on-going knowledge of where the user seems to be going and where he has been. Passing a Starbucks? Your cell phone may invite you in
for a coffee. The on-going technology challenge for sensor makers is to reduce the size, cost and power consumption of the sensor package (see Figure 2).