Many people have tried to define the Internet of Things. But we all know the essential element: To build interconnected products.
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IoT systems are not complicated, but designing and building them can be a complex task. And we already have all the tools we need today to start making the IoT a reality.
Your first step in building an IoT device is to figure out how it will communicate with the rest of the world. Your choice of communication technology directly affects your device’s hardware requirements and costs. So which networking technology is the best choice?
Let’s take a factory as a typical case for an IoT system. A factory would need a large number of connected sensors and actuators scattered over a wide area. A wireless technology would be the best fit.
This is a wireless sensor network. Data from each sensor passes through the network node-to-node. The nodes in a wireless sensor network are low-cost devices, so they can be deployed in high volume. They also operate at low power so that they can run on battery, or even use technologies such as energy harvesting.
An edge node acts as a gateway between the wireless sensor network and the Internet. It can also perform local processing, provide local storage, and can have a user interface.
The battle over the preferred networking protocol is far from over. And there are multiple candidates.
The first obvious networking candidate for an IoT device is Wi-Fi, because it’s everywhere. Certainly, Wi-Fi can be a good solution for many applications. Almost every house that has an Internet connection has a Wi-Fi router. However, Wi-Fi needs a fair amount of power. There are a lot of devices that can’t afford that level of power. For example: sensors located in places that are difficult to power from the grid.
But there are newer networking technologies that allow for the development of low-cost, low-power solutions. These technologies support the creation of very large networks of very small, intelligent devices.
Some of the R&D efforts to build these kinds of low-power networks include: Low-power radios that allow several years of battery life; energy harvesting as a power source; mesh networking for operation without human intervention; and new application protocols that allow devices to work autonomously.
One of the major pieces of low-power wireless is the IEEE 802.15.4 radio standard. It was released in 2003. Radios that meet this standard provide the basis for low-power wireless systems.
Power consumption of commercial RF devices is now cut in half compared to only a few years ago. And we are expecting another 50% reduction with the next generation of devices.
Devices must also perform their tasks in the shortest time possible to save energy. This means that their transmitted messages must be as small as possible. So this has implications for protocol design. And it is one of the reasons why 6LoWPAN has been adopted by companies such as ARM and Cisco.
6LoWPAN provides encapsulation and header compression mechanisms that allow for briefer transmission times. At Micrium, we believe that any protocol that carries IP packets has an advantage over all others. The requirements for IoT devices are so diverse that a single technology just can’t meet all the requirements for range, power, size and cost. But we believe that 6LoWPAN will be the choice for wireless sensor networks and for other IoT systems that need IP-based protocols.
If your IoT network is local and machine-to-machine, then the wireless protocols we’ve discussed are good candidates. But if your goal is to remotely control devices or otherwise transmit data over the Internet, you’ll need IPv6.
If at all possible, it’s crucial that your IoT networks all make use of the suite of Internet protocols. That’s UDP, TCP, SSL, HTTP, and so on. And your networks must support IPv6. Why? Because the current IPv4 standard faces a global addressing shortage, as well as limited support for multicast, and poor global mobility.
IPv6 provides more addresses than there are grains of sand on Earth. Or to put it another way, that a million trillion trillion addresses per person. With IPv6, it is much simpler for an IoT device to obtain a global IP address, which enables efficient peer-to-peer communication.
The importance of IP to the Internet of Things doesn’t automatically mean that non-IP networks are useless. It just means that non-IP networks will require a gateway to reach the Internet.
IoT PCB ways to care for Startups
Given that IoT devices are so recent, you would assume that getting an IoT printed circuit board (PCB) project off the ground starts by reinventing the wheel and experiencing a great deal of technical headache. That may be a misconception.
Nevertheless it doesn’t indicate IoT startups have a very clear way to fame. Facing them is quite a few design and manufacturing concerns which are completely unique to these small products. These considerations have to be thought about for the fresh IoT product to be successful.
On the plus side, it’s vital for IoT startups to know that the basic foundation for a successful awesome product exists. This implies experience and knowledge involving the design, fabrication and assembly of these kinds of superior products are accessible. Also, the best advice is for prudent IoT product business owners and innovators to become aware of the counsel that expert electronics manufacturing services or EMS providers have to offer. These corporations in addition to their engineering team members already have conducted the job with groundbreaking IoT companies in Silicon Valley participating in the initial phases of this emerging industry.
The PCB of an IoT product is a special beast than the traditional one, which is a great deal larger and flat. IoT units, on the other hand, are made up generally of either rigid-flex or flex circuit assemblies, which include their own sets of design layout, fabrication and assembly considerations and intricacies.
A principal thing to consider is to hunt for seasoned designers who have undertaken a lot of rigid-flex PCB designs. PCB space for an IoT product is scarce. So you want the designer to have firsthand layout experience to correctly design key elements on that compact space.
Additionally, nearly all IoT systems aren’t stationary; they sustain sizeable movement and folding. Here, the seasoned designer plays a significant role in working out bend ratios and lifecycle iterations as a important part of a design. Some other key design layout considerations involve signal trace thickness, number of rigid and flex circuit layers, copper weight and stiffener placement. Stiffeners are widely used on flex circuits to guarantee elements connected to the flex circuit keep on being firmly in position to avoid movement.
Some other consideration is through-hole component positioning in rigid-flex circuits. What makes that critical? A majority of IoT appliances are based on surface mount device placement. But nonetheless , there could be through-hole elements, which are typically attached to either the rigid part or the flex area of the board. Through-hole elements are usually utilized to connect input/output or I/O signals to the exterior world. Doing this, those signals can be displayed by using an LCD or LED monitor. Through-hole component placement is a very important account in an IoT item because when applied on the flex area of the board, proper stiffeners need to be designed and used for excellent assembly.
Last of all in the layout category, the heat that elements bring in has to be thought about. IoT systems are becoming more complicated with rigid-flex and flex circuits featuring in excess of 12 – 14 layers. Several systems are digital. But nonetheless , gradually more analog systems are being exercised in IoT systems. Analog circuitry results in somewhat more heat than digital ones. This means heat expansion plus contraction rate must be thought about. In tech lingo, it is called the Coefficient of Thermal Expansion or CTE and the appropriate remedy for it.
Deciding on the best fabricator is a must and is linked to the EMS enterprise you have chosen. The fabricator you need must have IoT PCB fabrication experience. Among key considerations here are assuring good adhesions in between layers on both rigid and flex circuit sides, bearing in mind all the vital calculations and obtaining a thorough knowledge of when current transfers from the rigid side to the flex side.
Such fabricators also must possess an in-depth know-how about extremely little components for example 0201 and 00105 device packages, package-on-package, and the use of fine-pitch ball-grid array or BGA packaged devices.
They also should have expertise in designing boards with truly tight tolerances in terms of footprint for those types of BGA devices, in terms of up-to-date capabilities like laser direct imaging for putting the solder mask on the board. They must have laser drills for via drilling with sizes of 5 mils or under because these IoT products could be so compact that a typical drill size of 5 to 8 mils might not be enough. They could require to go to a 3 mil, meaning you must have an state-of-the-art laser drilling capability in house.
In the event that you’re placing via-in-pad, it’s a fantastic way to utilize the small land that’s available on the rigid-flex board, but it presents trouble for assembly. If vias are not entirely planar or flat in shape, it could be a challenge over the assembly of those tiny BGA packaged devices. The reason is non-planar surfaces might put at risk the integrity of solder joints.
Occasionally via in pads leave bumps if they’re not scrubbed thoroughly after adding the vias and gold finish on the top. When there are bumps, then the solder joints in the assembly for those tiny BGA balls in those IoT devices may not be an ideal joint. This may create spotty connections, which can be a larger issue to cope with and take care of. It all boils down to which EMS enterprise you’re using because they’re the ones who will find the fabrication facility to make a thriving IoT device for you.
It’s very important to pay a visit to seasoned EMS companies that have productively assembled IoT and wearable PCBs because they have unique tooling and fixtures readily obtainable, which are required for assembly to ensure components are placed properly, exactly and the printing is practiced properly.
Printing can be a headache for IoT systems. If it’s a rigid-flex board, then you can find a change between thicknesses of the rigid and flex circuit portions, indicating a special fixture is required to retain the complete rigid-flex board planar or completely flat to help effective printing to become reached.
Startups must be well prepared to pick the ideal manufacturing partners and EMS enterprises. Doing this they can be sure they have sufficient experience early in advance to get the multitude of design, fabrication and assembly details effectively performed because they are essential to a lucrative and timely IoT product launch.