What are Embedded Systems and how do they play a role in IoT?
An embedded system is a computer system – a combination of hardware and/or software – that serves an essential function in a larger electrical system [1]. It usually controls some sort of physical operation and is, hence, often a real-time system.
Internet of Things (IoT) refers to a system of multiple devices communicating with each other directly and indirectly to serve a specific purpose. IoT is commonly associated with “smart” technology, especially within the home. This includes devices that allow the user to control the thermostat, lighting, or monitor camera activity via a remote device such as a smartphone.
For example, a pacemaker, a lower power consuming device that is placed in or near a patient’s heart to read abnormal signals and then rectify these by pulsing the required signals to the heart, is an embedded system.
This same pace maker could be set up to transmit the signals that it reads to a server that logs all this data and check if there is a abnormality. Additional signals could be transmitted to this same server from probes all across the patient’s body for more specific and accurate readings. Using all this data, the server could learn patterns in the specific person’s heartrate, resulting in more accurate error detection. The system could be set up to immediately alert the concerned doctor and the patient’s family mobile with the location, the condition and other statistics of the patient (again, collected with more sensors and embedded systems). This flow and interconnection of information through computing devices, often embedded systems, is referred to as Internet of Things (IoT) [2].
Reference
- “Embedded System.” Wikipedia, Wikimedia Foundation, 11 May 2020, en.wikipedia.org/wiki/Embedded_system.
- Burgess, Matt. “What Is the Internet of Things? WIRED Explains.” WIRED, WIRED UK, 16 Feb. 2018, www.wired.co.uk/article/internet-of-things-what-is-explained-iot.
Challenges of IOT Embedded System Design
The design of embedded systems compatible with the internet of things (IOT) presents many unique challenges in areas of flexibility, security, power, testing, safety, and cost management
- Flexibility: As more network architectures and protocols are created, older embedded systems need to be able to handle them using nothing but their unchangeable systems.
- Security: Embedded systems want to minimize required hardware, but by being connected over the IOT they must account for internet based attacks and its entire world of network security. This all creates a constant weighing of how much a design can be minimized while still being secure.
- Power: Most embedded systems ideally want to enter sleep modes to balance battery life with operation time, but using the IOT a device must constantly be listening which creates a large drain on power. To balance battery vs listening designers might try to choose more efficient hardware, or come up with a way to only be listening part of the time.
- Testing: IOT based embedded systems must not only be tested and verified like normal hardware, but they also need to go through network testing. Because network testing is so different from hardware testing the process would likely require multiple engineers with different skill sets.
- Safety: A networked system presents unique challenges for safety when paired with an embedded system because loss of connection, bad signals, part breakdown, and more can happen, but the designer wants to minimize hardware. Deciding what safety precautions are necessary and what can be ignored for simpler design and area can be difficult
- Cost Management: As indicated above, designers want to minimize area and obviously cost but various aspects make it impossible to design with only the bare necessities for functionality and cheapest parts. Because of the difficulty of weighing the design factors, advising companies exist to help find the optimal balance between cost and quality.
References
[1] https://www.einfochips.com/blog/hardware-design-challenges-of-the-embedded-internet-of-things-iot/
RS-485 Serial Protocol and IoT
Most electronics hobbyists and engineers are familiar with communications protocols such as I2C, and SPI. These are great methods for working with devices such as microcontrollers and integrated circuits and work well in most applications. However, there are some other protocols that were developed for use within more “noisy” environments like manufacturing facilities or vehicles that have lots of EMF noise caused by motors and moving machinery. This post will focus on the RS-485 protocol.
RS-485 is a serial communications protocol that can operate in half-duplex or full-duplex mode [1]. This makes it a good communication for a variety of applications as it can support up to 32-nodes with controller/node configurations. It also has a maximum data rate of 10 Mbit/s and distances up to 1,200m, with there being a tradeoff of needing lower frequencies at higher distances and vice-versa, based on transmission line physics. One of the main benefits of the RS-485 protocol is that it uses differential signaling via a twisted pair of wires for physical connections. This greatly reduces signal interference as any EMF picked up by the wires are “cancelled out” by the signals propagating in the opposite direction.
While I2C and SPI work well for short-range communications, RS-485 is a great choice for systems that are spread out across longer distances. One interesting comparison is when looking at RS-485 as an alternative to WiFi or Bluetooth communications for Smart Homes [2]. Using RS-485 in this capacity would require more physical devices to set up the infrastructure but could still be used to manage sensors and actuators within a living environment in a secure way that could reduce the overall EMF signature of the system.
There are many potential applications for RS-485, although it is mainly used in industrial manufacturing and automotive systems to connect programmable logic controllers (PLCs). It can also be used in computer systems for communication between system controllers and peripheral devices such as disk drives. One interesting niche application that it is used for is lighting and sound control systems for performances using the DMX512 standard and is widely used within this area for performance artists just as DJs and electronic performers.
The main limitations with RS-485 is that it is only a physical layer standard. This means that all capabilities of higher levels of the network stack need to be taken care of in software or by other devices. For smaller and more simple applications this isn’t a problem, but as systems scale in complexity there can be a lot of design overhead needed to prevent collisions and manage data.
If you’d like to check out some of the basics of the RS-485 protocol, there is a great design guide on the basics by Texas Instruments at [3].
Reference
[1] Wikipedia Contributors, “RS-485,” Wikipedia, 14-Oct-2019. [Online]. Available: https://en.wikipedia.org/wiki/RS-485. [Accessed: 24-May-2020].
[2] J.-L. Aufranc, “GetWired Aims to Make RS-485 Wired Home Automation Affordable and User-friendly (Crowdfunding),” CNX Software – Embedded Systems News, 13-Feb-2020. [Online]. Available: https://www.cnx-software.com/2020/02/13/getwired-rs-485-wired-home-automation-affordable-user-friendly/. [Accessed: 24-May-2020].
[3] T. Kugelstadt, “The RS-485 Design Guide Application Report The RS-485 Design Guide,” Feb. 2008.
Embedded IoT Examples
As the world gets more connected, with 5G networking coming into play, we will be seeing the world of IoT explode. There will be millions of these devices in the near future that we will be interacting with daily. [1] To give some example that we will see now and in the near future, here is a list of common devices using IoT.
- IoT Sensors – Sensors can range from ultrasonic to infrared to temperature. These devices are constantly reading information that will be used to update and give more information for real time decision making in control systems. [2]
- IoT Tracking and Monitoring Systems – From GPS to RF frequencies, embedded devices can keep track of the location of where they are reading these signals. With higher inter-connectivity using the Internet of Things, it is possible to bring a large mesh of information together to make better decisions on routing and scheduling of transport. More information on transportation is available here.
- Smart Barcode Readers – Now when you go to certain Fred Meyers, you have the capabilities to use their Smart Barcode readers known as \ “Shop, Pay, Go”. These devices allow you to bring the barcode scanner with you while you shop, scan each item and place it in your cart. You then just pay on the smart bar code reader to check out. These devices will need to be in constant connection to the store’s network to verify transactions and inventory. No social interaction needed when shopping. Wow! [3]
- SmartGrid – The Power Grid is getting smarter and smarter each year. One example of this is using automated metering with Smart Meters. These devices have been implemented all over the country and are being locally used at PG&E. A Smart Meter is different than the traditional meter because it is in constant connection with the utility through a secure wireless network, updating the customer’s electricity use every 15 minutes. This saves the utility time and labor, reducing the need to go to every site and read the meter. This information can also be used to forecast the customers usage. [4]
- Smart Farming – Smart Farming is ushering a new era of how we farm. There are now devices located in some farms that are constantly reading in data about the soil (moisture, temperature, pH, etc.) so the proper irrigation and fertilization can happen. Drones and tractors are smart as well, constantly using GPS and GIS to located and record information about the land to provide the most suitable method of farming in each location. These technology advances can bring in greater yields and profits for the farmer.
Here is a list of interesting tutorials of IOT project that can implemented at home.
- This video explains how to connect Alexa with Arduino, ESP8266 and Raspberry Pi. This just a setup to add any device you want.
- This video explains how to connect a controlled scrolling display using a google assistant.
- This video provides a basic tutorial for serial communication with Processing, an application that allows access to your computer’s hardware and internet connection
- This video shows how to use esp8622 module for connecting the Wi-Fi to open a door
Reference
[2] Softwaretestinghelp.com. 2020. 10 Powerful Internet Of Things (Iot) Examples Of 2020 (Real-World Apps). [online] Available at: <https://www.softwaretestinghelp.com/best-iot-examples/> [Accessed 25 May 2020].
[4] PGE “Smart Meters” https://www.portlandgeneral.com/-/media/public/our-company/energy-strategy/documents/smart-meters.pdf
[5]G. W.-J. 3, G. W. -, Author Guest WriterGuest writers who are especially keen on exploring IoT and related technologies, Guest WriterGuest writers who are especially keen on exploring IoT and related technologies, and Guest writers who are especially keen on exploring IoT and related technologies, “IoT Applications in Agriculture,” IoT For All, 03-Mar-2020. [Online]. Available: https://www.iotforall.com/iot-applications-in-agriculture/. [Accessed: 25-May-2020].
Prototyping Boards for IoT embedded
When it comes to working on embedded IoT projects the best way to design and develop a working system is to try things out with development boards that have the chip set you want to work with, since they are usually low cost and very accessible. Which makes them very viable when it comes to prototyping designs. Allow me to introduce some of the most popular development boards that are readily available on the market currently:
Arduino family of boards, if you want a low cost solution for prototyping then your best option would be to get the Arduino boards. That one that is most often used is the Arduino Uno which is one of the most accessible development boards that are available. Although many Arduino boards don’t come stock with Bluetooth and WiFi capabilities they are still very popular, to give them WiFi and Bluetooth capabilities oftentimes it’s just as simple as adding a module. The wide availability and the low cost of the boards make them very attractive for prototyping and learning purposes. [1,2,3]
The Raspberry Pi family, from the pi 4 to the pi zero these boards are readily available and are widely used for IoT purposes since most of them come stock with Bluetooth and WiFi capabilities, if they don’t have those options stock you could easily opt-in for aftermarket add-ons to suit your need since they are so versatile. Currently the The top of the line version is the Raspberry Pi 4 model B, which offers a slew of on-board peripheral support such as I2C, SPI, HDMI, UART, and SDIO. [1,4]
Nvidia Jetson Nano, if you want more power and speed than this is the board that you want for your project or prototype. This board from Nvidia sports a Quad-core ARM® A57 that can reach clock speeds up to 2GHz. It also has a 128-core NVIDIA Maxwell™ architecture-based GPU that can be used for AI and machine learning purposes. For memory this guy has 4 GB 64-bit LPDDR4. When it comes to raw power and speed there isn’t really a competitor that can beat the Jetson at it price range and accessibility. One of the cooler things about the board is that it has support for Linux or Tegra (which is a Nvidia developed OS). [5]
These are only some of the development boards that are out there, the ones that are listed are there to show what is possible are a different price range and accessibility. It goes from the cheapest being the Arduino family to the most expensive Nvidia Jetson Nano, accessibility follows the same trend as well.
Reference
[1] B. Jordan, “10 Open Source Embedded Development…,” EEWeb Community, 11-Jul-2018. [Online]. Available: https://www.eeweb.com/profile/kumarb/articles/10-open-source-embedded-development-boards. [Accessed: 26-May-2020].
[2] “Best IoT Development Kits: 2019 Overview Guide,” Postscapes, 01-Nov-2019. [Online]. Available: https://www.postscapes.com/cellular-internet-of-things-development-kits/. [Accessed: 26-May-2020].
[3] YoungWonks, “We bring you the 10 most popular prototyping and development boards in 2020,” YoungWonks. [Online]. Available: https://www.youngwonks.com/blog/Top-10-IoT-boards-for-2019. [Accessed: 26-May-2020].
[4] J. MSV, “10 DIY Development Boards for IoT Prototyping,” The New Stack, 10-May-2019. [Online]. Available: https://thenewstack.io/10-diy-development-boards-iot-prototyping/. [Accessed: 26-May-2020].
[5] Nvidia, “NVIDIA Announces Jetson Nano: $99 Tiny, Yet Mighty NVIDIA CUDA-X AI Computer That Runs All AI Models,” NVIDIA Newsroom Newsroom, 22-May-2020. [Online]. Available: https://nvidianews.nvidia.com/news/nvidia-announces-jetson-nano-99-tiny-yet-mighty-nvidia-cuda-x-ai-computer-that-runs-all-ai-models. [Accessed: 26-May-2020].
IoT Networks
There are different ways to connect IoT devices to the internet, and they have their trade-offs. The first option would be the Wired and Wireless Networks such as Ethernet, WiFi, Bluetooth, ZigBee and others. They offer great connectivity and less transmission latency. However, these type of networks have some environmental restrictions since they’re hard to apply on a global scope. Another type would be the M2M networks, such as 2G, 3G, 4G and 5G which offer great connectivity and less transmission latency. Although these types of networks are very effective, they have their cons as well, such as having high power consumption, high cost and large footprint. Another choice is the Low Power Wide Area Networks (LPWANs), and they’re very effective for this type of usage since they are cheap, have a low power consumption, have a high range. However, LPWANs has a relatively higher transmission latency [1].
Another choice would be the Narrow Band IoT (NB-IoT) networks, and it’s specifically developed for IoT based on the 4G technology. NB-IoT networks offer a very low power consumption, low cost, easier deployment and others pros. However, NB-IoT networks yield some security issues since they can’t be built as private networks [1].
As discussed above, each type of network has its own pros and cons, and it comes to the designer to decide which choice they’re going to utilize depending on their needs.
Reference
[1] “Overview of IOT Networks,” IOT Factory. [Online]. Available: https://iotfactory.eu/iot-knowledge-center/overview-of-iot-networks/. [Accessed: 27-May-2020].
