Tag Archives: IoT

Progress in the World of Internet of Things

Although many in the electronics field lambast the Internet of Things (IoT) as an inappropriate or inadequate acronym, IoT is a space to huge to be confined to these narrow adjectives. In reality, IoT requires a blanket description, as it covers a vast arena. Problems arise from compartmentalization and although various spaces such as industrial and medical have established a big head start, others have yet to launch their true separate identities.

For the electronics designer this means taking the general palette of IoT features and functionalities and tailoring them specifically to the application at hand. The designer must be knowledgeable about state-of-the-art technologies such as those required for cloud connectivity, wireless design infrastructure, interface ergonomics, and internal power management. The designer must be familiar with the methods of manifesting them in their design, as these may be critical aspects.

For instance, there are several suggestions for scaling the IoT from smart factories to smart homes. Although there are blueprints for pollution reduction, city traffic management, and electrical energy distribution, the purveyors of industrial-grade operating systems do not yet have a detailed plan for the smart home.

According to Wei Tong, Product Marketing Manager of Dialog Semiconductors, wearable technologies can do far more than simply functioning as personal items. Using Bluetooth, a communications standard protocol, wearable devices can connect to a larger network, allowing them to communicate with other devices via beacons and sensors, thereby manifesting the larger Internet of Things.

However, despite the birth of the phrase “the Internet of Things” 18 years ago, and the first connected IoT device 35 years ago, consumers are yet to adopt wearable IoT in mass quantities. According to Nick Davis, this is due to two factors—first, ease of use, or lack thereof, and second, lacking the purpose or serving the wrong purpose.

For instance, take the case of “smart” light bulbs. Some are easy to connect to and control with smartphones, while others give users a hard time. According to Nick Davis, once people face such difficulties, they tend to give up on the entire IoT and smart device concept.

Another example Nick Davis gives is that of a smart toaster or smart refrigerator and the purpose they serve. According to Nick, most companies have not done proper market research into the actual requirement of people who use toasters and refrigerators, and what the consumers expect in such smart devices. However, several new products on the market are potentially useful to designers.

Another example of wrong purpose is the video sunglasses from Snap, the parent company of Snapchat. These are basic sunglasses with a video camera attached. They allow users to capture and post videos more easily to Snapchat. According to Nick, Snap is stuck with hundreds of thousands of their unsold spectacles. Apparently, Snap did not realize that people are not very keen on walking around taking videos with their eyewear.

Despite such debacles above, newer products are appearing on the market that help designers achieve better energy-efficient IoT products, voice recognition engines, and flexible and smart motor-control options that are also lightweight and compact.

Tuning an IoT MEMS Switch

Menlo Microsystems, a startup from GE, is making a MEMS-based switch fit into a broad array of systems related to Internet of Things (IoT). Already incorporated into medical systems of GE, they can tune the chip to act as a relay and power actuator for several types of industrial IoT uses, including using it as an RF switch suitable for mobile systems.

Menlo first described their electrostatic switch in 2014. They have designed it with unique metal alloys deposited on a substrate of glass. The arrangement creates a beam that a gate can pull down, making it complete a contact and allow current to flow. Compared to a solid-state switch, this electrostatic switch requires significantly less power to activate and to keep it on. This single proprietary process creates products for several vertical markets.

The low power consumption of the device allows it to handle high currents and power switching. Unlike traditional switches, the MEMS switch does not generate heat, and therefore does not require large, expensive heat sinks to keep cool.

Currently, a tiny research fab run by GE is making the switch. Menlo expects to produce it in larger quantities in mid-2018, through Silex Microsystems, a commercial fab in Sweden. According to Russ Garcia, CEO of Menlo, their biggest challenge is to get the technology qualified in a fab producing commercial items.

The device has huge opportunities as it can replace a wide variety of electromechanical and electromagnetic power switches and solid-state relays. Menlo is planning to roll out several varieties of reference boards incorporating its MEMS chips, which will be helpful in home and building automation, robotics, and industrial automation.

For instance, IoT devices such as the smart thermostat from Nest face an issue of efficiently turning on or off high power systems such as HVACs. According to Garcia, the Menlo switch can do this while drawing almost zero current. Additionally, the Menlo switch offers a two-order reduction in the size of power switches and their power consumption.

It took a 12-year research effort by GE to incubate the design of the MEMS switches. They discovered that reliability issues were related to materials MEMS used, and overcame the issues with alternate unique metal alloys for the beams and contacts of the switch including generating a novel glass substrate. This combination allows billions of on/off switches to handle kilowatts of power reliably.

The medical division of GE will be among the first users of the chip. They will use the chip to replace a complex array of pin diodes in their MRI systems. This replacement by MEMS switches can knock off $10,000 from the cost of each MRI system. This includes the payment to five PhDs who presently tune each of the machines with pin diodes. The new MEMS switch will allow an automatic programming of the system.

Although GE will be an exclusive user for the chips in their MRI systems, Menlo is discussing future uses of the chip with other MRI makers as well. According to Garcia, GE wants to create a new strategic component supplier for the chips. Menlo is also planning to use the chips for RF switches.

Extending IoT with the Raspberry Pi

Recently, the Raspberry Foundation has updated its embedded Compute Module with a faster ARM processor. This will help developers and businesses build new IoT devices. The new Compute Module 3 (CM3) comes with a powerful new option and embedded compute capabilities for device makers interested in the Internet of Things (IoT).

Although not to be confused with the Single Board Computer, the Raspberry Pi (RBPi), with which the CM3 also shared the latest update, is a tiny form-factor ARM-powered SBC originally developed to help both kids and adults learn computer programming.

Launched with the same form factor as that of the RBPi, the CM3 was specifically targeted at business and industrial users. While the RBPi is a completely standalone device, the CM3, on the other hand, is a module intended for plugging into a separate Printed Circuit Board. The primary aim of the Compute Module is to let vendors and developers develop customized products quickly.

The new CM3, like the RBPi3, also uses the same Broadcom system-on-chip (SoC), the ARM BCM2837. The ARM Cortex A53 design forms the base for the SoC BCM2837, which is a 1.2 GHz, quad-core chip running on 64 bits. As a bonus, the standard CM3 has an on-module eMMC flash memory of 4 GB.

Other than the standard CM3, the Raspberry Pi Foundation also has a CM3L or Compute Module 3 Lite version. With the CM3L, users can wire up their choice of an SD card interface or eMMC memory. While the CM3L also comes with the same BCM2837 SoC, the on-board RAM is still restricted to 1 GB only.

Along with the CM3 and the CM3L, the Raspberry Pi Foundation is also releasing the new Compute Module IO Board V3 (CMIO3). This will provide developers with a starter breakout board to which they can connect their Compute Module.

The CMIO3 offers designers a starting template for designing with the Compute Module, providing them with a quick method to experiment with the hardware and to build and test a system. Once the experiment succeeds, they can proceed with the expense of fabricating a custom board. The CMIO3 also provides the necessary USB and HDMI connectors to make up the entire system that boots up and runs the Raspbian OS, or any other OS you select.

Although the Raspberry Pi Foundation has only recently released new Command Modules, next generation large-format displays based on the modules are already available from the consumer electronics vendor NEC, as they had early access to them.

The idea behind the Compute Modules is to provide a cost-effective and easy route to making customized products using the hardware and software platforms of the RBPi. The modules provided the team in the garage the same technology that the big guys already had. The Module takes care of the complexity of routing the core power supply, the high-speed RAM interface, and the processor pins, while allowing a simple carrier board provide the basics in terms of form factor and external interfaces. The form factor of the module follows that of the inexpensive, easily available, standard DDR2 SODIMM.

IOT: The Internet of Things Helps Manage Decisions

In any era, one of the characteristics of a good leader has always been their ability to take a good decision with the limited information available to them. According to the 26th US President Theodore Roosevelt, the best thing to do in a moment of decision is doing the right thing, the next best thing is doing the wrong thing, while the worst that anyone can do is doing nothing. This brings us to the IOT

Expectations are the Internet of Things (IoT) will be networking billions upon billions of things someday. Even if considering this hype, there is no ignoring the fact that IoT is already affecting management decisions worldwide. Business managers, at all levels, are receiving information that is more relevant as soon as they need it. Connected devices are making this possible, coupled with advances in collection of data and analytics. All that is affecting the decisions they are making, and business performance and operation is seeing a deep and lasting impact.

The broad range of nascent and mature technology available with the Internet of Things ranges from microscopic sensors called smart dust, to autonomous robots, to remote monitoring and RFID tags. Predictions from Gartner forecast that from the 6.4 billion connected IoT devices in 2016, the year 2020 will witness a jump to 21 billion devices worldwide. That means over the next five years, the number of internet-connected things will swell by three times.

Keeping this explosive growth in mind, Industry Week has conducted a study—the Industry Week Industrial Internet of Things Analytics Research Study. It gauges the usage of present and future state of IOT technology by US manufacturers. It also includes a special focus on data collection and analytics, as the IoT is more about the ability to collect, analyze, and use the massive amounts of data generated by the devices rather than about the devices themselves.

For their research, Industry Week has defined the Internet of Things as products and machines containing embedded electronics and sensors, with software for network connectivity that enables control and remote data collection. They also define analytics as the process of extracting insights from raw data, enabling better decision making.

The study reveals more than half the manufacturers reporting they are currently using the IoT technology for collecting machine data. Other companies say they are collecting the data from sensors embedded within their products—the percentage here is smaller, but significant at 44%. Both groups are using the data from machine and product for generating management reports and for performing root cause analysis as and when problems crop up.

According to the study, less than 25% of the manufacturers are using IoT for purposes that are more proactive. This includes improving business decision making through data mining or development of optimization models. All this indicates the presence of a potential source of competitive advantage as well as a huge opportunity.

Surprisingly, about one third of the manufacturing leaders said they did not have any strategy specifically geared towards the Internet of Things. However, most of these manufacturers reported their senior leaders are driving the organizations to be more data centric and analytical.

Use the Raspberry Pi for the Internet of Things

Barriers are coming down between operational technologies. Barriers such as were existing between industrial hardware and software for monitoring and controlling machines and the ERP systems and other information technology people typically use when operating and supporting their business. Manufacturers are having an exciting time as new opportunities are emerging every day for improving the productivity. Along with the rise in the challenges, there are innovations in creating new sources of customer value.

Data is not a new thing for manufacturers. In fact, there was enough data with manufacturers long before the Internet of Things and Big Data came into existence. Although manufacturers have been collecting and analyzing machine data for ages, they can now replace their legacy equipment and systems. With the explosion of the Internet of Things, the flow of data on the customers’ side is also ramping up. Networked products are tightening the connection between customers and manufacturers, with service capabilities expanding and creating entirely new revenue models.

With every organization wanting to participate in the Internet of Things, and IT professionals wanting to know how to add IoT skills to their resume, it is time to look at the different options for learning about IoT. Although there are many ways to gather this knowledge, nothing really can beat the hands-on experience.

The tiny single board computer, the Raspberry Pi or RBPi is one of the key learning platforms for IoT. Not only because this involves very low cost, but also because it offers a complete Linux server in its tiny platform. When you use the RBPi for learning about IoT, you will find that the most difficult thing to face is the picking the right project to make a start.
On the Web, you can find several thousand projects based on the RBPi. They involve the ambitious types, silly types, while some are really great for learning about Linux, RBPi, and the intricacies of the IoT.

When starting out with IoT projects and the RBPi, it is prudent to keep to a boundary – use some common sensors and or controller types. Custom-built hardware is fine for geeks, but for those who are just starting out with IoT, going wild with hardware builds can lead you astray.

While selecting a project, choose one that has something interesting going on for the control software. While it would be foolish to start with an epic development project, just to make a meaningful learning experience, simply calling pre-existing scripts and applications is also likely to cause a loss of interest.

Choose a fun project to start with. Of course, you will be training for the IoT. Nevertheless, training in the form of drudgery is no fun. Therefore, select a project that will want to make you move forward and continue your journey with the education.

You can buy individual sensors from the market and hook them up to your RBPi. However, as a beginner, you might be well off buying a kit for a specific use such as a single wire temperature sensor or a humidity sensor. Later, when more confident, you could move on to Hardware Attached on Top or HATs for the RBPi.

Cayenne on a Raspberry Pi

If you are building projects for IoT or the Internet of Things, a single board computer such as the Raspberry Pi, also known as the RBPi, can be a great asset. Moreover, with Cayenne installed on the RBPi, you have a drag-n-drop IoT project builder that the developers of the Cayenne software, myDevices, claims is the first in the world.

Therefore, now it is easy to connect your RBPi to a mobile or online dashboard. On the other side, you have a breadboard ready to connect relays, lights, and motion sensors. Of course, you have always had the freedom to write an application, read multiple pages of documentation, and take time to learn new programming languages, write pages of code, and then debug them to make it all work together. Alternatively, you can reduce the time you spend preparing for your project, because Cayenne helps to get your project up and running in a fraction of the time, and you can build your automation projects in minutes.

With Cayenne, myDevices makes all this possible, because they created Cayenne for makers and developers eager to build and prototype amazing IoT projects with their RBPi, as quickly as possible. Users get a free Cayenne account, which allows them to create unlimited number of projects. There is also a full-fledged IoT maker support capability that allows remote control of sensors, actuators, motors, and GPIO boards.

On the free account, you can also store unlimited amount of data that the hardware components collect including triggers and alerts, providing all the tools necessary for automation. That allows you to set up custom dashboards and threshold alerts capable of highlighting your projects with fully customizable drag-n-drop widgets.

According to myDevices, Cayenne is the first of its kind of builder software that empowers developers to use its drag-n-drop features for creating quick IoT projects and host their connected device projects. Cayenne allows remote control of hardware, displays sensor data, store data, analyze it, and do several other useful things.

In the Cayenne platform, users can find several major components, such as:

The main Application – useful for setting up and controlling IoT projects with drag-n-drop widgets.
The Online Dashboard – set this up through a browser to control your IoT projects.
The Cloud – useful for storing devices, user and sensor data, actions, triggers, and alerts. Additionally, it is also responsible for data processing and analysis.
The Agent – useful for communicating with the server, hardware, and agent for the implementation of outgoing and incoming alerts, triggers, actions, and commands
Whenever you press a button from the online dashboard or the Cayenne app on your mobile, the command travels to the Cayenne Cloud for processing and travelling to your hardware. The same process takes place in the reverse direction as well. Cayenne offers users plenty of features.

You can connect to your IoT through Ethernet, Wi-Fi, or mobile apps. It is possible to discover and setup your RBPi on a network via Ethernet or Wi-Fi. Dashboards are customizable and widgets are drag-n-drop. It is possible to remotely access your RBPi, shut it down, or reboot it. Users can add sensors, actuators, and control extensions connected to the RBPi, and many more.

What are Wearable PCBs Made of?

The Internet of Things market is growing at a tremendous speed. Among them, wearables represent a sizeable portion. However, there are no standards governing the small size PCBs or Printed Circuit Boards for these wearables. The unique challenges emerging in these areas require newer board level development and manufacturing experiences. Of these, three areas demand specific attention – surface material of the boards, RF or microwave design and RF transmission lines.

Surface material of the boards

PCB materials are typically composed of laminates. These can be made of FR4, which is actually fiber-reinforced epoxy, of polyamide, Rogers’s materials of laminates, with pre-preg as the insulation between different layers.

It is usual for wearables to demand a high degree of reliability. Although FR4 is the most cost-effective material for fabricating PCBs, reliability is one issue the PCB designer must confront when going for a more expensive or advanced material.

For example, with applications requiring high-speed and high frequency operation, FR4 may not be the best answer. While FR4 has a Dk or dielectric constant of 4.5, the more advanced Rogers series materials can have a Dk of 3.55-3.66. The designer may opt for a stack of multilayer board with FR4 material making up the inner cores and Rogers material on the outer periphery.

You can think of the Dk of a laminate as the capacitance between a pair of conductors on the laminate, as against the same pair of conductors in a vacuum. Since there must be very little loss at high frequencies, the lower Dk of 3.66 for a Rogers’s material is more desirable for high frequency circuits, when compared to FR4, which has a Dk of 4.5.

Typical wearable devices have a layer count between four and eight. With eight layer PCBs, the layer structuring offers enough ground and power planes to sandwich the routing layers. That reduces the ripple effect in crosstalk to a minimum, while significantly lowering the EMI or electromagnetic interference. For RF subsystems, the solid ground plane is necessarily placed right next to the power distribution layer. This arrangement reduces crosstalk and system noise generation to a minimum.

Issues related to fabrication

Tighter impedance control is an important factor for wearable PCBs. This results in cleaner signal propagation. With today’s high frequency, high-speed circuitry, the older standard of +/-10% tolerance no longer holds good and signal-carrying traces are now built to tolerances of +/-7%, +/-5% or even lower. This influences the fabrication of wearable PCBs negatively, as only a limited number of fabrication shops can build such PCBs.

High-frequency material such as Rogers require to have a +/-2% of Dk tolerance and +/-1% is also a common figure. In contrast, for FR4 laminates it is customary to have Dk tolerances of +/-10%. Therefore, Rogers’s material presents far lower insertion losses when compared to FR4 laminates.
In most cases, low cost is an essential factor. Although Rogers’s material offers low-losses with high-frequency performance at reasonable costs, commercial applications commonly use hybrid PCBs with FR4 layers sandwiched between Rogers’s material. For RF/microwave circuits, designers tend to favor the Rogers’s material over FR4 laminates, because of their better high-frequency performance.

Low-Power GPU for IoT

The Mali Graphical Processing Units or GPUs from ARM are popular because of their cost efficiency. ARM has optimized them to provide energy efficient, high performance graphics in the smallest possible area of silicon. As a result, not only low- to mid-range smartphones, but also tablets and DTVs are also using Mali cost efficient GPUs as ARM offers a diverse selection of scalable solutions involving both graphics-only and graphics plus GPU Compute technology.

ARM offers the Mali-400MP, which is the first OpenGL, ES 2.0, multi-core GPU with leading area efficiency and the Mali-450MP, which offers approximately twice the performance of the Mali-400MP. However, these are not suitable for the Internet of Things, as these devices require extremely low levels of energy consumption. For the IoT, ARM has released a new low-power GPU. Useful for wearable and other IoT gadgets, the new 32-bit Mali-470MP from ARM claims smartphone-quality graphics, while requiring only half the power used by the Mali-400MP, using the same process geometry.

For cutting the power consumption in the Mali GPUs, ARM targeted three prime areas and made a range of micro-architectural optimizations. They updated most of the processing blocks within the chip to a scheduling pipelines operating on quads. They reduced the frequency of control and state-update operations. They also increased the amount of clock gating in areas including LI caches and completed the bypass blocks.

In general, most graphic processors use floating-point arithmetic for better performance. However, using floating-point arithmetic consumes a lot of power. In Mali-470MP GPUs, ARM prefers using fixed-point arithmetic in places where it does not affect performance. By scrutinizing every milli-watt across the entire SOC, ARM was able to tune the efficiency of Mali-470MP, making it relevant for devices operating with low power budgets, but requiring sophisticated graphics such as wearables, IoT devices and entry-level smartphones.

According to Dan Wilson, Product Manager of ARM, the Mali-470MP is highly power-efficient because it is optimized for the OpenGL ES 2.0 API and its drivers. As most of the devices using Android, Android Wear and Tizen devices use the OpenGL ES API, Mali-470MP can replace the previous generation of GPUs from ARM. Additionally, there is no need to re-optimize the applications for the new GPU.

Just as users are accustomed to vibrant displays and touch interfaces on smartphones, Mali-470MP is expected to bring immersive experiences to wearables, because of its greater power efficiency and support for the OpenGL ES 2.0.

Designers have the freedom of using the multi-core configurable Mali-470MP with both 32- and 64-bit CPUs. These include processors such as the ARM Cortex-A7 and the Cortex-AS3. As IoT devices do not need to address more than 4GB or memory, ARM has designed the new CPU as a 32-bit device. However, Mali-470MP offers optimal energy efficiency when used for screen resolutions up to 640x640p in single-core configurations and up to 1080p for multi-core configurations.

However, the new GPU from ARM is not available in the market yet, and licensees will most likely be able to ship products based on the new Mali-470MP only by the end of 2016.

Devices Running on WiFi Power

Mobile devices are now radically smaller and more powerful than those available in the last decade were. They are also able to tackle more technology-related tasks compared to their erstwhile brethren. However, as their capability grows, they need to consume more power. With the Internet-of-Things and wearable technologies gaining increasing recognition from users, the need to keep them ‘on’ all the time is raising the topic of the best methods to power them.

Imagine that you have multiple sensors embedded around your home, tracking temperature changes by the minute and governing your thermostat to help conserve energy. How nice it would be if all the sensors operated without batteries. For then, you could rest assured that they, in tandem with the thermostat, will be properly monitoring the energy consumption. With battery-operated sensors, you will need to check on the status of each sensor frequently to prevent the system going haywire.

Now, engineers have developed a new communication system that does not require batteries to operate it. Instead, it uses existing Wi-Fi infrastructure and radio frequency signals to provide Internet connectivity to devices. Very soon, your battery-less wristwatch or other wearable devices will be able to communicate directly with other gadgets for storing information about your daily activities on your online profiles.

Earlier research by a group of engineers at the University of Washington had shown that it is possible for low-power devices to run off wireless waves such as those belonging to radio and TV. Their most recent work has taken them a step further. Now these devices, apart from operating without batteries, can send their signals to laptops or smartphones, using only wireless waves to generate the required power.

According to Shyam Gollakota, an assistant professor at the University of Washington, this is an essential step for Internet of Things to really take off. Potentially billions of battery-free devices will need connectivity when embedded in everyday objects. The research can now provide WiFi connectivity to devices and they claim their process consumes several orders of magnitude less power than that typically required for WiFi connectivity.

A tag made by the researchers listens for WiFi signals that a local router exchanges with a laptop or a smartphone. An antenna on the tag selectively reflects or absorbs the signal to encode it. The activity produces tiny changes in the signal strength of the radio waves that other devices can detect and decode.

The method allows central devices such as laptops, tablets and smartphones the ability to communicate with other low-power devices and sensors. The central devices exchange data with sensors that lie within a range of about two meters and do so at the rate of one kilobit per second. For example, a pair of smart socks could relay information about your jog to the jogging app on your phone. Although there is a chance for the radio signals to be buried in noise, the system works because the devices know the specific pattern that they need to look for.

That allows low-power Internet of Things to communicate easily with a large swarm of devices around them because of the prevalence of WiFi.

Raspberry Pi and the Intel Edison

The Intel Edison is an extremely small computing platform suitable for embedded electronics. Intel has packed the Edison with many technical goodies within its tiny package. That makes it a robust single board computer, powered by the Atom SoC dual-core CPU. It includes an integrated Bluetooth LE, Wi-Fi and a 70-pin connector. A huge number of shield-like blocks are available to stack on top of each other on this connector.

Do not be misled by its small size, as the Edison packs a robust set of features within the tiny size. It has a broad spectrum of software support, along with large numbers of IO, delivering great performance with durability. Its versatile features are a great benefit to beginners, makers and inventors. The high-speed processor, Wi-Fi and Bluetooth radio on board makes it ideal for projects that need low power, small footprint but high processing power. These features make the Edison SBC suitable for those who cannot use a large footprint and are not near a larger power source.

In addition, the Intel Edison Mini Breakout exposes the native 1.8V IO of the Intel Edison module. On this board is a power supply, a battery charger, USB OTG power switch, USB OTG port, UART to USB Bridge and an IO header.

So, how does the Intel Edison SBC compare with the RBPi or the Raspberry Pi SBC? The first question that comes to mind when starting a comparison between the two is the lack of a USB port on the Edison to plug in the keyboard and mouse. Compared to the RBPi, the Edison also lacks video output, has low processor speed, higher cost and it is not possible to use the IO connector without an extra board.

Although Intel claims it as an SBC, unlike the RBPi, the Edison is a module meant for deeply embedded IoT computing. On the other hand, the RBPi has always been a low-cost computing terminal to be used as a teaching tool. That the RBPi platform also has hardware hack-ability is a bonus feature and purely incidental.

The Edison, a deeply embedded IoT computing platform, does not have video output because usually, Wi-Fi enabled robots do not need video. Since wearables do not need keyboard and mouse, the Edison does not have a USB port. To keep power consumption on the low side for portable applications, Intel has deliberately kept the processor speed low.

Although the Edison is comparatively higher-priced as compared to the RBPi, the difference is lower when you add the cost of an SD card, a Wi-Fi card and a Bluetooth dongle to that of the RBPi. Not only does the Edison integrate all this, it is more of a bare ARM A9 or A11 SoC that can be integrated easily into a product.

Finally, three things need highlighting. The Edison has a Quark micro-controller; it operates at 1.8V and is very small. The RBPi, without the addition of the communication modules, occupies about 93 cubic centimeters, whereas the Edison and its breakout board together require only 14. The RBPi requires about 48 square centimeters of footprint, while the Edison needs only 17.