IoT Available to Everyone

The world of technology is changing faster than ever these days, and the pace of new technology introduction to wireless applications has not subsided. As transmission standards have changed to accommodate Internet of Things (IoT) devices, it’s never been easier for a wireless enthusiast to try their hand at designing a new modulation scheme, and there are plenty of new sensors available to pair with a wireless link. These technologies are also more accessible to everyone than ever before. Let’s talk about each of these developments and how we can get our hands on this inexpensive and universally available technology right now.

Low power wide area network (LPWAN) radio technologies are available on cellular infrastructures and have been around for a few years now. Narrow band Internet of Things (NB-IoT), Long Term Evolution Machine Type Connection (LTE-M and LTE-MTC), and enhanced Machine Type Communication (eMTC) are popular. The advantage of these technologies is their leverage of existing cellular towers that are used for voice and high bandwidth traffic. However, a device that needs only occasional reporting and control does not require a high bandwidth, and since many are battery-operated, there was a need for lower power and lower bandwidth standards that these technology standards enable.

Other technologies that do not leverage existing cellular networks and must have infrastructures built anew include Sigfox, LoRa/LoRaWAN, and NB-Fi to name only a few. The disadvantage to these is requiring an uplink to couple to the broader internet. While network operators provide this uplink as a service, it is yet another computer network system to negotiate.

However, the cellular network operators are huge companies and it’s not realistic to compete effectively with them. The best course is to buy “time” on their networks by adopting modems that comply to their standards and then pay a monthly use plan.

The non-cellular networks can be built out with modest funds and with the limitation that the geography they cover is not great. They are certainly not worldwide until they are connected to a server that performs the bridging to the internet.

The good news is that access to cellular networks, and the chips and modules to build your own low-power network, are available from DigiKey. DigiKey sells cellular network data plans, too, that cost as little as $3.00 per month for 300 KB of data and international service (see Figure 1). All you need is a cellular operator-certified modem and your device can be “online” worldwide. The modems and the chips that are included in those modems are also available.

Figure 1: DigiKey cellular data plans.

Electronic solutions in the form of modules continue their dramatic growth. Instead of requiring the expertise yourself to design at the chip level, you can obtain a radio prebuilt and certified. This not only reduces necessary RF technical acumen, it also gets products to market more quickly. I did a spot check recently after looking up the chips used in modules and then looked to see what type of customer was buying each. It was surprising to see that companies having the necessary acumen were not only buying the same chips that were on the modules, they were also buying the modules, and both were being purchased in quantities of thousands of units. This supports the notion that it can be better to get to market early with a less cost-optimized product to test the market for a new product. If the market is large enough, the product can then be cost-optimized by going all the way down to the chip level. But there is even a level lower than chips that I am calling the waveform level.

Software Defined Radios (SDRs) allow a developer to experiment with entirely new modulation schemes. If you have a unique need and the expertise, you can develop your own radio standard. Even if you don’t have the expertise, experimenting with an SDR can teach you a lot.

One such SDR is the Analog Devices Advanced Learning Module PLUTO (ADALM-PLUTO) from Analog Devices and available for off-the-shelf shipping from DigiKey (see Figure 2). These units cost less than $150 USD as of August 2019. They interface to a personal computer over a USB link, contain an FPGA that is easily reconfigured, have extensive support for the programming language Python, and can transmit and receive signals over a range from 325 MHz to 3.8 GHz. If you really want to know and use RF, you can start at this level.

Figure 2: ADALM-PLUTO SDR available from DigiKey. (Image source: Analog Devices Inc.)

Back to the idea of specific products, sensors by the hundreds in the form of chips and modules proliferate. Here are some of the things that can be sensed along with the number of items in stock (SKUs) from DigiKey (as of the date of this blog posting):

• Proximity Sensors (10,150 items)
• Sensors, Transducers Temperature Sensors - Analog and Digital Output (4,256 items)
• Sensors, Transducers Specialized Sensors (914 items)
• Sensors, Transducers Gas Sensors (371 items)
• Sensors, Transducers Position Sensors - Angle, Linear Position Measuring (2,961 items)
• Sensors, Transducers Pressure Sensors, Transducers (30,778 items)
• Sensors, Transducers Humidity, Moisture Sensors (570 items)
• Sensors, Transducers Current Sensors (2,033 items)
• Sensors, Transducers Optical Sensors - Ambient Light, IR, UV Sensors (1,240 items)
• Sensors, Transducers Optical Sensors - Distance Measuring (137 items)
• Sensors, Transducers Evaluation Boards - Sensors (2,589 items)
• Development Boards, Kits, Programmers Magnetic Sensors - Position, Proximity, Speed (Modules) (4,266 items)
• Sensors, Transducers Optical Sensors - Photoelectric, Industrial (9,979 items)
• Sensors, Transducers Motion Sensors - Accelerometers (1,730 items)
• Sensors, Transducers Image Sensors, Camera (1,551 items)

In all, DigiKey offers more than 210,000 different sensors.

Any one of these sensors, or any combination of them, can be incorporated into a product that can tie to the internet via a wide variety of wireless options.

Another tool to enable your wireless product development is the DK IoT Studio (see Figure 3). This rapid application development (RAD) tool is free-of-charge from DigiKey. From a web-based integrated development environment (IDE), you can choose a ready-made embedded microcomputer board, configure it in the IDE, and download your configuration including IDE-generated open-source code onto your board. That board can communicate with a device that is either tethered to a host via wires or wirelessly tethered via Bluetooth or Wi-Fi and can then send whatever data it has to the internet for reception by a paired smartphone. Options exist to scale this to larger settings which do require a nominal fee. For example, an online project that shows the connection to the internet of a “window blinds controller” can be found on maker.io. Code to modify DK IoT Studio to add features of your own can be found here on DigiKey’s eewiki website.

Figure 3: DigiKey's DK IoT Studio

Happy developing and may the Internet of Things bring your connected devices to the world.