A practical guide for engineers to find Thevenin voltage in DC and AC circuits and apply it in real-world circuits for power systems, sensors, amplifiers, and efficient load analysis.

How to Find Thevenin Voltage: A Complete Practical Guide for Engineers

Optimizing Network Design and Performance through Strategic Hardware Selection


Navigating Network Infrastructure: Patch Panel vs Switch

<section><p>Cable assemblies and wire harnesses are integral to electronics manufacturing, especially in PCBA box builds. Both are necessary for connecting and integrating components and systems. However, cable assemblies and wire harnesses serve distinct purposes that must be understood for good PCBA design.</p><p>A wire harness is essentially an organized grouping of wires or cables, either encased in a cost-effective, lightweight protective sheath or simply bound together with cable ties. Its primary role is organizational, consolidating multiple electrical wires into one unit for space efficiency and secure, neat routing.</p><p>In contrast, cable assemblies are bundled wires or cables protected by a robust outer layer, and act as transmission lines for signals or power between different parts of a system or between systems.<br><a href="https://www.macrofab.com/box-build-assembly/" target="_blank">A PCBA box build</a>, also known as systems integration, refers to the assembly of a complete electronic product. Within this process, the careful integration of cable assemblies and wire harnesses is essential for ensuring dependable connections, protecting against environmental factors, and transmitting signals accurately. This article will focus on these components and compare their roles in modern electronic assembly.</p><h2><br></h2><h3>What is a Wire Harness?</h3><p>At a high level, a wire harness assembly is a collection of wires or cables designed to transmit signals or electrical current. It is a method of organizing and routing wires within complex electronic systems.</p><p>As part of this bundled group, certain wires or cables may branch from the main group at certain points. This branching allows the wire to connect to a particular component or terminal within the system. These branching points are referred to as “active breakouts” or ends.</p><p>Additionally, for protection, this entire group of bundled wires, including the branch-out points, is often encased in a lightweight protective sheath.</p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzgyNDg0MTA0LTE3MTU3ODI0ODQxMDQucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="Img1" class="fr-fic fr-dii"><h3>Basic Components of a Wire Harness</h3><p>A wire harness is primarily made up of three essential parts: the wires, connectors, and housing or protection.</p><h3>Wires and cables</h3><p>A wire is a flexible conductor, which may or may not be insulated, used as a common pathway to transmit electrical signals or power from one point to another. Cables, on the other hand, begin with two or more wires bundled together Cables are more flexible than wires due to their multiple wires, and can transfer higher amounts of electricity.</p><p>When shopping for wires and cables for your wire harness design, familiarity with industry-specific jargon is crucial. Below are some key terms associated with wires and cables:</p><ul><li><strong>Wire Diameter:</strong> Refers to the overall thickness of a wire. It’s the sum of the conductor’s actual diameter and the insulation’s thickness.</li><li><strong>American Wire Gauge (AWG):</strong> A standardized system used predominantly in the United States to denote wire or cable thickness.</li><li><strong>Standard Wire Gauge (SWG):</strong> This is the British counterpart to AWG.</li><li><strong>Braid:</strong> A structure created by weaving together thin metallic strands, often copper. This woven pattern serves as a conductor and is known for its strength and durability, making it apt for demanding applications.</li></ul><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzgyNDg1NDEzLTE3MTU3ODI0ODU0MTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="Img2" class="fr-fic fr-dii"><h3>Connectors</h3><p>Connectors, as the name suggests, facilitate the connection of these wires to other components or systems, ensuring a seamless flow of electricity. They come in two primary types: <strong>plugs and receptacles.</strong> Plugs are the male connectors, meant to be inserted into their female counterparts, the receptacles.</p><p>A connector typically has a front part, where the actual connection between plug and receptacle takes place, and a back part which attaches to the wire or cable, providing a secure and stable connection.</p><p>When dealing with connectors in wire harness assemblies, several terms are commonly used:</p><ul><li><strong>Contacts:</strong> These are the actual conductive parts within the connector, facilitating the electrical connection.</li><li><strong>Cable Ties:</strong> Also known as zip ties or tie wraps, these are fastening devices used to bundle wires and cables together.</li><li><strong>Mating Cycle:</strong> The number of times a connector can be connected and disconnected while still maintaining its functionality.</li><li><strong>Polarization:</strong> Features designed into the connector to prevent wrong-way insertion.</li><li><strong>Strain Relief:</strong> A design feature or component that prevents wires from bending at extreme angles at the connector’s entry point, reducing the risk of wire damage or disconnection.</li><li><strong>Terminal:</strong> The end part of a wire where it makes a connection.</li><li><strong>Ring Terminal:</strong> A type of connector that is shaped like a ring, making it easy to attach to a screw or stud. It’s commonly used for grounding purposes or making connections to busbars and components with stud-style terminals.</li><li><strong>Loose Terminal:</strong> Individual terminal connectors that aren’t pre-inserted into a housing or connector body. They offer flexibility during assembly as they allow for custom connector configurations.</li><li><strong>Assembled Connector:</strong> a connector that has been pre-assembled, meaning it already has terminals inserted into a housing. It speeds up the PCB box build assembly process.</li><li><strong>Bellmouth:</strong> A flared or widened entry of a terminal, making wire insertion easier and reducing the risk of wire damage during insertion.</li><li><strong>Crimp:</strong> A method of joining a terminal to a wire by deforming or “pinching” them together, creating a secure mechanical and electrical connection.</li><li><strong>Double Crimp:</strong> The compression of two or more wire barrels at a single terminal.</li><li><strong>Crimp Height:</strong> Refers to the height or thickness of the terminal after it has been crimped onto the wire. It’s an essential metric to ensure a good quality crimp connection.</li></ul><h3>Protection</h3><p>A wire harness assembly, while facilitating the transmission of signals or power, also exposes its components to various environmental and operational hazards. Among these, corrosion, stress, strain, and electromagnetic interference (EMI) are most prevalent.</p><p>Exposure to moisture and corrosive substances can result in the corrosion of wires and terminals. Such corrosion can introduce high resistance and impedance mismatch, hindering efficient power transfer and potentially causing system breakdowns.</p><p>Furthermore, during the lifecycle of a wire harness, mechanical stress from installation maneuvers or regular operation—like pulling, bending, or twisting—can wear out connectors and cables. This strain is particularly detrimental at the connection points, risking disconnections or wire breaks that interrupt the electrical pathway.</p><p>Additionally, every electrical device releases a certain degree of electromagnetic radiation. This radiation, when it interferes with another device’s operation, is labeled as <a href="https://www.macrofab.com/blog/introduction-to-emc-compliance/" target="_blank">Electromagnetic Interference (EMI)</a>. In essence, EMI prompts wires or cables to inadvertently receive unwanted electrical signals. This unintended reception can disturb the wire’s own signals and jeopardize the performance of sensitive electronic systems.</p><ol><li>Protection of Wires:<ul><li><strong>Insulation:</strong> Most wires are coated with an insulating layer that not only prevents electrical leakage but also provides a first line of defense against environmental hazards like moisture or chemicals.</li><li><strong>Shielding:</strong> Especially for wires susceptible to EMI, a shielding layer, often made of braided copper or a metallic foil, surrounds the wire, preventing external electromagnetic fields from disturbing the signal within.</li><li><strong>Conduits and Sleeves:</strong> In extremely harsh environments, wires are encased in conduits or protective sleeves that provide an added layer of protection against mechanical or environmental damage.</li></ul></li><li>Protection of Joints and Connections<ul><li><strong>Sealed Connectors:</strong> These are designed to keep out moisture, dust, and other contaminants. They play a vital role in preventing corrosion at the connection points.</li><li><strong>Strain Reliefs:</strong> Integrated into connectors, these prevent undue stress on the wire at its joint, reducing the risk of wear and tearor disconnection.</li><li><strong>EMI/RFI Filtering:</strong> For connections especially vulnerable to electromagnetic or radio frequency interference, connectors with built-in filters can be used to block unwanted interference.</li></ul></li></ol><h3>Different Types of Wire Harnesses</h3><p>Wire harnesses vary based on application, environment, and material composition. Here’s a summary table of different types of wire harnesses.</p><h2><p>The Difference Between Cable Assemblies and Wire Harnesses</p></h2><p>While cable assemblies and wire harnesses both organize wires, they have key differences.</p><p>The table below offers a concise comparison of the similarities and differences between a wire harness and a cable assembly:</p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzgyNDg1MzY3LTE3MTU3ODI0ODUzNjcucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="Table" class="fr-fic fr-dii"><p>Table</p><h2><br></h2><h3>What is a Cable Assembly</h3><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzgyNDg1NDc0LTE3MTU3ODI0ODU0NzQucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="Img3" class="fr-fic fr-dii"><p>A cable assembly consists of multiple wires or cables enclosed within a singular protective sheath, typically made from rubber, vinyl, or pressure-extruded<br>thermoplastics such as polyurethane.</p><p>In contrast to wire harnesses, which bundle multiple individually sheathed wires or cables, a cable assembly integrates all its wires into one unified casing. Also, the protection layer used in a cable assembly offers a higher degree of protection compared to the sheathing<br>used in wire harnesses. This makes cable assemblies especially suited for extreme environments requiring enhanced protection.</p><p>Additionally, cable assemblies come equipped with multiple connectors at their active ends, facilitating connections to devices or other cables.</p><h3>Different Types of Cable Assemblies</h3><p>Similar to wire harnesses, cable assemblies are not one-size-fits-all. They are tailored to suit a variety of applications, industries, and environmental conditions. Below are some distinct types:</p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzgyNDg1Nzg3LTE3MTU3ODI0ODU3ODcucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="Cable Assembly" class="fr-fic fr-dii"><p>Cable Assembly</p><h2><br></h2><h3>The Difference Between Cable Assemblies and Wire Harnesses</h3><p>While cable assemblies and wire harnesses both organize wires, they have key differences.</p><p>The table below offers a concise comparison of the similarities and differences between a wire harness and a cable assembly:</p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzgyNDg2MDg5LTE3MTU3ODI0ODYwODkucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="Similarities and differences" class="fr-fic fr-dii"><h2><br></h2><h3>Applications for Cable Assemblies and Wire Harnesses</h3><p>Cable assemblies and wire harnesses find their way into a multitude of applications, underlining their versatility and crucial role in a wide range of industries:</p><ul><li><strong>Automotive Industry:</strong> Both cable assemblies and wire harnesses can be found in everything from the basic wiring systems that control lights and indicators to the more complex setups in modern vehicles, facilitating multimedia systems, navigation, and advanced driver assistance systems.</li><li><strong>Agricultural Industry:</strong> The modern agricultural sector heavily relies on machinery and equipment. Cable assemblies ensure these machines can withstand outdoor elements, while wire harnesses ensure that the internal electronics of these machines function seamlessly.</li><li><strong>Industrial and Manufacturing:</strong> In factories and production lines, wire harnesses and cable assemblies provide structured wiring setups that make maintenance easy.</li><li><strong>Military:</strong> Reliability is paramount. Both components ensure communication devices and navigation systems function consistently, even under extreme conditions.</li></ul><p>In every mentioned sector, product success is deeply tied to the excellence and dependability of its PCBA box build. Central to this are wire harnesses and cable assemblies. They guarantee organized connections that withstand environmental challenges, and enhance overall functionality.</p><p>Therefore, correctly integrating these components in the box build process leads to long-lasting products, contented customers, and the ensuing sustainability and expansion of a business.</p><h3>Conclusion</h3><p>You might often hear cable assemblies and wire harnesses used interchangeably, but they fulfill distinct roles in electrical systems. Cable assemblies provide strong external protection and connectivity, while wire harnesses focus on optimizing internal organization and saving space.</p><p>Choosing the right cable assembly and wire harness can be challenging. If you work in the hardware tech industry, it’s imperative to understand these differences. When completing your box build, make sure to choose a company who can help you make the right decisions.</p></section><p><a href="https://www.macrofab.com/box-build-assembly/" target="_blank">LEARN ABOUT MACROFAB’S BOX BUILD CAPABILITIES</a></p><hr><section><h5 id="isPasted">About MacroFab</h5><p>MacroFab offers comprehensive manufacturing solutions, from your smallest prototyping orders to your largest production needs. Our factory network locations are strategically located across North America, ensuring that we have the flexibility to provide capacity when and where you need it most.</p><p>Experience the future of EMS manufacturing with our state-of-the-art technology platform and cutting-edge digital supply chain solutions. At MacroFab, we ensure that your electronics are produced faster, more efficiently, and with fewer logistic problems than ever before.</p><p>Take advantage of AI-enabled sourcing opportunities and employ expert teams who are connected through a user-friendly technology platform. Discover how streamlined electronics manufacturing can benefit your business by contacting us today.</p></section><p><br></p>

Cable assemblies and wire harnesses serve distinct purposes that must be understood for a good PCBA box build.

Cable Assemblies vs Wire Harnesses: Their Role in PCBA Box Builds

Decoding the Essentials: A Detailed Overview of Ladder Logic Symbols in Automation

Ladder Logic Symbols: A Comprehensive Guide

Automotive sensing system concept leveraging sensor fusion technology to aid self-driving cars on the street

Learn the powerful approach of combining data from multiple sensors to enhance the overall perception, reliability, and decision-making capabilities of various systems with ease.

Sensor Fusion: The Ultimate Guide to Combining Data for Enhanced Perception and Decision-Making

<h1 id="isPasted">How to Document Your PCBA Process for Better Results</h1><p>Time is only meant to allow things to not happen all at once, according to Einstein. But even his brilliant mind could get overwhelmed by too much information, as he also said, &ldquo;Paper is to write things down that we need to remember.&rdquo; You can take that as a small comfort next time you forget a password you haven&rsquo;t recorded.</p><p>A quality documentation process organizes all your necessary information to meet your needs. Quality production begins with documenting the entire design and manufacturing process. In this blog, we&rsquo;ll walk you through the types of documentation your project requires, how to streamline documentation processes, and how better documentation can speed up your PCBA project development.</p><h2>Types of PCBA Documentation</h2><p>PCBA manufacturing requires multiple documentation subsets to keep track of information flow, order materials, and regulate processes. Before manufacturing this includes:</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjY2OTg4MjEyNTQ2LTE2NjY5ODgyMTI1NDYucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="bill of materials" class="fr-fic fr-dii"></p><ul><li><br><ul><li><strong>Bill of Materials.</strong> The first step to successful manufacturing is a comprehensive and detailed parts list. Your BoM will be broken down into an eBoM (Engineering Bill of Materials) that lists all the parts, components, and materials within the design, and an MBoM (Mechanical Bill of Materials) which shows how the entire product is to be assembled physically.</li><li><strong>A Centroid File.</strong> This file, also known as XYRS(X-y-rotation-side), describes the orientation and positioning of each surface mount component, including its X and Y positions, its rotation, and whether it is mounted top or bottom. In addition, through-hole components require a separate component placement file.</li></ul></li></ul><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjY2OTg4MjEyNjYyLTE2NjY5ODgyMTI2NjIucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="electronic schematics" class="fr-fic fr-dii"></p><ul><li><strong>Electronic Schematics</strong> provides an organized view of electrical circuits located within the PCBA and are necessary for manufacturing.</li><li><strong>Design files.</strong> Design files contain additional information about layers and component placement, and vary depending on the EDA tool used.</li><li>You will encounter more paperwork after placing your order and the manufacturing process begins. Purchase orders, engineering changes, price variances, inventory releases, and invoices are among the items on the list.</li></ul><h3>How to Streamline PCBA Documentation Processes</h3><p>All best documentation practices begin with the same steps:</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjY2OTg4MjEyNzc5LTE2NjY5ODgyMTI3NzkucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="organize responsibilities" class="fr-fic fr-dii"></p><ol><li>Organize responsibilities logically by department. By doing this, information will remain within its appropriate area and will be easier to locate.</li><li>Assign roles and permissions so everyone can do their job. To maintain timelines and protect IP information, you must ensure that everyone has access to all the information they require. Also, &nbsp;provide only necessary access to documents.</li><li>Streamline data entry. To improve productivity and process efficiency, automate data capture as much as possible. Using a CM with an API (application program interface) will help you build and maintain your documentation more efficiently.</li></ol><p>With a connected online documentation platform, your team is able to access manufacturing data faster and deeper, resulting in better results.</p><h3>The Impact on Production Speed</h3><p>How do such changes affect real-world results? With an online PCBA documentation platform, you can expect to see the following benefits and direct impacts:</p><h4><strong>Simplified Quoting and Pricing</strong></h4><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjY2OTg4MjEyNjAwLTE2NjY5ODgyMTI2MDAucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="simplified quoting and pricing" class="fr-fic fr-dii"></p><p>By leveraging connected systems, companies can gain a deeper understanding of costs, lead times, and parts availability with the capability to better assess how scale and timeline decisions affect pricing.</p><p>It is also possible for your product managers and design engineers to get a better idea of potential costs and supply problems during prototyping, which will assist them during mass production.</p><h4><strong>Fewer Needed Design Changes</strong></h4><p>Using a manufacturing platform that supports widely used EDA tools makes it easy to drag and drop layouts and drill files. This type of platform enables you to identify manufacturing issues before you place an order due to the what-you-see-is-what-you-get simplicity.</p><h4><strong>Seamless Internal Operations</strong></h4><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjY2OTg4MjEyNzE1LTE2NjY5ODgyMTI3MTUucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="seamless internal operations" class="fr-fic fr-dii"></p><p>It is possible to avoid communication errors between departments by connecting online documentation strategies. By integrating data sharing, all team members will have access to the most recent information to make smarter decisions.</p><p>Communication histories can also be found in documents online, along with dates and times. Consequently, it is possible to keep track of how and when important decisions were made in the past. As a result, it is also possible to maintain an iteration history over time.</p><h4><strong>Improved Competitive Edge</strong></h4><p>Imagine what your business would become if it was unable to compete with its competitors. It is imperative to achieve an edge in operating efficiency in order to remain relevant and competitive. Late product launches have a real and negative impact on profits and brand reputation. By using an online platform, you can streamline your documentation processes and protect both.</p><p><strong id="isPasted">Recommended reading:&nbsp;</strong><span style="background-color: transparent;"><a href="https://www.wevolver.com/article/why-should-you-use-rigid-flex-pcb-assembly" rel="noopener noreferrer" target="_blank">Why Should You Use Rigid-Flex PCB Assembly?</a></span></p><h3>Conclusion</h3><p>There&rsquo;s no need to struggle with communication or efficiency. Throughout the PCB design lifecycle, connected manufacturing documentation platforms enable rapid deployment, better data management, and unlimited complexity.</p><h4>See How MacroFab Provides Tools for Your Success</h4><p><a href="https://macrofab.com/how-it-works/" target="_blank">How It Works</a></p>

Better documentation can speed up your project development 

Bringing a product to market late has a real and negative impact on profits and brand reputation.  In this blog, we go through the types of documentation your project requires and ways to streamline processes. 

How to Document Your PCBA Process for Better Results

An introduction to the world of artificial intelligence

What Is Artificial Intelligence and How Does It Work?

<p dir="ltr">Sensor fusion refers to the capability to combine input from different radars, LiDARs, cameras to create a single image of an environment around a vehicle.</p><p dir="ltr">Such a process is required as sensor imperfections are a certainty. No system can afford the luxury of operating under pristine, lab-grade conditions, where distractions never happen.</p><p dir="ltr">Aside from external disturbances in working conditions, there are also the sensor’s own issues—drifting, inaccuracies, or just plain crazy black box errors.</p><p dir="ltr">Sensor fusion is one component you’ll use to design this ‘better’ system.</p><p dir="ltr"><br></p><div class="fr-img-space-wrap"><span class="fr-img-caption fr-fic fr-dib" style="width: 788px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjE3MzY1OTQzNzk4LWV5SmlkV05yWlhRaU9pSjNaWFp2YkhabGNpMXdjbTlxWldOMExXbHRZV2RsY3lJc0ltdGxlU0k2SW1aeWIyRnNZUzh4TlRnek1qUXpPRGd3TURRd0xVRjFkRzl1YjIxdmRYTWdWbVZvYVdOc1pTQlRaVzV6YjNKeklEQXhJREV3TWpSd2VDNXFjR2NpTENKbFpHbDBjeUk2ZXlKeVpYTnBlbVVpT25zaWQybGtkR2dpT2prMU1Dd2labWwwSWpvaVkyOTJaWElpZlgxOS53ZWJwIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 788px;" class="fr-fic fr-dib" alt="Sensors used in autonomous vehicles"><span class="fr-inner" spellcheck="false">An example of typical sensors used to perceive the environment. Note that various vehicle manufacturers may use different combinations of sensors and might use all of the displayed sensors. For example, increasingly multiple smaller LIDAR sensors are being used, and long-range backward-facing RADAR can be incorporated to cover situations like highway lane changing and merging. The placing of the sensors can vary as well. Image: Wevolver</span></span></span><h3 class="fr-img-space-wrap2"><strong>What is sensor fusion?</strong></h3></div><p dir="ltr">You might be more familiar with sensor fusion if I call it “data fusion,” “information fusion,” or even “multi-sensor integration.”</p><p dir="ltr">These phrases are often mentioned like they’re the same thing.</p><p dir="ltr">Spoiler alert: they’re not.</p><p dir="ltr">But a sensor fusion system can involve all these principles at the same time.</p><p dir="ltr">By definition, sensor fusion is a process to join the measurement data from multiple measurement sessions, be it from different sensors or different instances, to get better measurement data than if you’re using a single sensor as your source of truth.</p><p dir="ltr">‘Better’ in this sense can be something as simple as a more accurate representation, more complete data, or even inferred information that isn’t directly measured by current sensors.</p><h3 dir="ltr">4 reasons to use sensor fusion</h3><p dir="ltr">Let’s face it:</p><p dir="ltr">Issues come up when you use sensors.</p><p dir="ltr">Whether it’s something caused by imperfection of the sensor itself, like noise and drifting, or an external factor, like an extraordinary operating condition.</p><p dir="ltr">Certain as they are, you can side-step these issues by strengthening your data stream with multiple sensors, whether they’re duplicates or heterogeneous sources.</p><p dir="ltr">Let’s say you want to measure the vibration of a bridge when a vehicle passes.</p><p dir="ltr">You left an accelerometer overnight, which transmits the data live to a computer in your office.</p><p dir="ltr">When you saw the data the next morning, you noticed that there’s an outlier in your data—a sudden burst in your accelerometer’s wavelength.</p><p dir="ltr">What happened there?</p><p dir="ltr">Did a particularly big truck just happen to pass by? Is it just plain sensor craziness? Or is there a cyclist who knocked the accelerometer out of its position?</p><p dir="ltr">Unfortunately, since you’re only using one sensor in this case, you’ll never know. And you’ll never know if the data your sensor recorded is accurate either.</p><p dir="ltr">This is where using multiple sensors and a sensor fusion algorithm helps.</p><ol><li dir="ltr">Adding a second (and third) sensor lets you compare the data. This improves the accuracy of your measurement results, so you can hypothesize about what happened at the bridge that night.</li><li dir="ltr">If there are outside interferences disturbing your sensor’s performance, you can use a second sensor that isn’t affected by this disturbance.<br>Thus, maintaining the consistency of your data stream.</li><li dir="ltr">If by any chance, your sensor is experiencing a breakdown in the middle of the operation, you don’t have to suffer from data loss as there are backup sensors available.</li><li dir="ltr">Get additional insights using the same set of sensors, reducing the complexity, number of components, and cost of operation for your system.</li></ol><p dir="ltr">The margin of error for your system gets smaller when you use sensor fusion to merge sensory data from multiple sources, as opposed to trusting a single sensor to perform exceptionally well throughout the entire operation.</p><h2 dir="ltr">Types of sensor fusion systems</h2><p dir="ltr">When observed from a high-level, the setup you’ll need for a sensor fusion network is fairly simple.</p><p dir="ltr">You have the sensors, which give an input of raw data to the estimation framework, where the algorithm will transform your raw data into a specific output.</p><p dir="ltr">Depending on the algorithm you’re using, the output could be an entirely unique set of information, or it could be a more accurate version of your raw data.</p><p dir="ltr">However, the algorithm, the architecture of the overall system, and the sensor setup will depend on what sensors you have and what information you want to get out of this sensor fusion system.</p><p dir="ltr">Let’s start with the easier part and get to know the types of sensor fusion systems, based on the setup, architecture type, and levels of fusion.</p><h3 dir="ltr">Sensor setup</h3><p dir="ltr">Arguably the simplest categorization, there are three commonly used sensor fusion configurations: competitive (or redundant), cooperative, and complementary. <a href="https://link.springer.com/chapter/10.1007/978-1-4613-8997-2_7" target="_blank">(Durrant-White, 1990)</a></p><ol><li dir="ltr"><strong>Competitive</strong><br>In a competitive or redundant setup, your sensors observe the same object. By having multiple sensors set up to observe the same state, you can improve the reliability and accuracy of your system, and the confidence level of your measurement data.</li><li dir="ltr"><strong>Cooperative</strong><br>Just like a competitive setup, cooperative systems also observe the same object. Rather than using the data to decide which data stream should be passed on, you can use a cooperative setup to get new insights into your observed environment by combining the raw data.</li><li dir="ltr"><strong>Complementary</strong><br>A complimentary setup observes two different objects. Similar to a cooperative setup, merging the data lets you form a global point of view of the observed environment.</li></ol><h3 dir="ltr">Architecture type</h3><p dir="ltr">Based on its architecture, there are three main types of sensor fusion systems: centralized, decentralized, and distributed. <a href="https://www.hindawi.com/journals/tswj/2013/704504/" target="_blank">(Castanedo, 2013)</a></p><p dir="ltr">There is also a hierarchical type, which combines the decentralized and distributed system through a hierarchy, but let’s stick to the three main types for this brief explanation.</p><ol><li dir="ltr"><strong>Centralized</strong><br>Within a centralized architecture, the data fusion process is done directly on the control system. This simplifies the architecture, but puts a strain on the control system, making it slower and less efficient.</li><li dir="ltr"><strong>Decentralized<br></strong>In a decentralized architecture, your measurement data is combined at a data fusion node, with feedback from your local network of sensors and other data fusion nodes in your system. While this is more efficient than a centralized system, your communication line gets complicated quickly if you use a lot of sensors and data fusion nodes in your system.</li><li dir="ltr"><strong>Distributed</strong><br>A distributed system processes your data locally at the source before sending it into an intermediate fusion node, which then produces a global view of your observed environment.</li></ol><h3 dir="ltr">Levels of data fusion</h3><p dir="ltr">Depending on your application, your sensor measurement data will transform into different levels of data as it goes through your system. Ackoff states that the <a href="http://www.systems-thinking.org/dikw/dikw.htm" target="_blank">hierarchy of your data</a> can take the form of data, information, knowledge, and wisdom.</p><p><br></p><div class="fr-img-space-wrap"><span class="fr-img-caption fr-fic fr-dib" style="width: 690px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjE2NzUxMjM4NDc3LURJS1cgcHlyYW1pZC5wbmciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 690px;" class="fr-fic fr-dib" alt="DIKW hierarchy wisdom hierarchy knowledge hierarchy information hierarchy"><span class="fr-inner" spellcheck="false">DIKW Pyramid</span></span></span><p class="fr-img-space-wrap2">&nbsp;</p><p class="fr-img-space-wrap2">In this pyramid, data is raw data. Or basically just an input from your measurement system —whether it’s numbers, symbols, signals, or others—that you can’t really make sense of just yet.</p></div><p dir="ltr">The next level, information, is still data but this time tagged with the relevant context so it becomes more useful and easily visualized.</p><p dir="ltr">While knowledge is obtained by assembling the pieces of information and relating it to what you want to find out. In short, knowledge is where the data starts to become useful for you.</p><p dir="ltr">The top of our pyramid, wisdom, is a little harder to define. But just like everything else before it, it builds on knowledge. This time to ask more abstract questions like ‘why’ and eventually get a decision.</p><p dir="ltr">This DIKW ties in neatly to the three main levels of data fusion. Based on the levels of data fusion, there are three categories of sensor fusion systems:</p><ol><li>Low-level fusion moves at a data level. It takes your raw data as input and returns a more accurate version of your raw data as output.&nbsp;</li><li>Mid-level fusion moves at the feature level. It takes observed features as input and produces a new feature as output. Here, features are just information inferred from a collection of raw data, including contextual information processed from various sensors or a priori information.</li><li>High-level fusion combines decisions, represented from sources as input, to produce a more accurate decision as output.</li></ol><p dir="ltr">As you can see, this categorization only moves from one level to the next. The problem is when you have a system that crosses levels. Here, you can use <a href="https://www.sciencedirect.com/science/article/pii/B9780128111536000014" target="_blank">Dasarathy’s categorization</a>, which uses input and output data format as the parameter.</p><p dir="ltr"><br></p><div class="fr-img-space-wrap"><span class="fr-img-caption fr-fic fr-dib" style="width: 650px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjE2NzUxNzIxNjYwLVNlbnNvcl9GdXNpb25fQ2xhc3NpZmljYXRpb25fYnlfRGFzYXJhdGh5LnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 650px;" class="fr-fic fr-dib" alt="sensor fusion classification by Dasarathy"><span class="fr-inner" spellcheck="false"><span contenteditable="true" spellcheck="false">Classification by Dasarathy</span></span></span></span><h2 class="fr-img-space-wrap2">&nbsp;</h2><h2 class="fr-img-space-wrap2">How sensor fusion prevents cars from crashing</h2></div><p dir="ltr">Autonomous vehicles need a lot of input to get a sense of their ever-changing environment.</p><p dir="ltr">To prevent crashes, the system needs a model of the external and internal state, which will need to be measured using a combination of several sensors, including radar, lidar, and cameras.</p><p dir="ltr">Naturally, each sensor has its own strength and weakness. To get an accurate depiction of the environment and improve the robustness of the system, you’ll need to combine the data from each sensor.</p><p dir="ltr">For instance, you need cameras to get more context about the environment and classify objects. On the other hand, lidar and radar are better at determining the distance of the car from an object.</p><p dir="ltr">The table below depicts how these three sensors can benefit from each other.</p><p dir="ltr"><br></p><table style="width: 100%;"><tbody><tr><td style="width: 19.8985%;"><br></td><td style="width: 20%; text-align: center;"><strong>RADAR</strong></td><td style="width: 20%; text-align: center;"><strong>LiDAR</strong></td><td style="width: 20%; text-align: center;"><strong>CAMERA</strong></td><td style="width: 20%; text-align: center;"><strong>FUSION</strong></td></tr><tr><td style="width: 19.8985%;">Object detection</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Pedestrian detection</td><td style="width: 20%; vertical-align: middle; text-align: center;">-</td><td style="width: 20%; vertical-align: middle; text-align: center;">O</td><td style="width: 20%; vertical-align: middle; text-align: center;">+</td><td style="width: 20%; vertical-align: middle; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Weather conditions</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">-</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Lighting conditions</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">-</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Dirt</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">-</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Velocity</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Distance - accuracy</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Distance - range</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Data density</td><td style="width: 20%; text-align: center;">-</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Classification</td><td style="width: 20%; text-align: center;">-</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td style="width: 19.8985%;">Packaging</td><td style="width: 20%; text-align: center;">+</td><td style="width: 20%; text-align: center;">-</td><td style="width: 20%; text-align: center;">O</td><td style="width: 20%; text-align: center;">+</td></tr><tr><td colspan="5" style="width: 99.8731%;">+ = Strength; O = Capability; - = Weakness</td></tr></tbody></table><p dir="ltr"><br></p><p dir="ltr">There are many more applications of sensor fusion in autonomous vehicles. It’s also needed for many other safety features required by an autonomous vehicle, such as 3D object detection, tracking, and occupancy mapping. <a href="http://users.isy.liu.se/rt/lundquist/Publications/Lundquist2011.pdf" target="_blank">(Lindquist, 2011)</a></p><h2 dir="ltr">Want to use sensor fusion in your next project?</h2><p dir="ltr">So now that you’ve peeked into the world of sensor fusion, there’s one more topic we haven’t covered yet. Just because it’s such a broad topic.</p><p dir="ltr">Your sensor fusion algorithm, the core of your sensor fusion system.</p><p dir="ltr">It will largely depend on what you’re trying to do. The algorithm you’ll need to get more precise data for your lab-contained robots will most likely differ from one to prevent crashes on autonomous cars.</p><p dir="ltr">After you’ve decided on the requirement of your system and which sensors to use, you can start thinking about which algorithm you’ll use to create a sensor fusion system that matches your needs.</p><p dir="ltr">To get a basic idea about what kind of algorithm you need, you can start with the most popular filters for sensor fusion: <a href="https://www.mathworks.com/videos/series/understanding-kalman-filters.html" target="_blank">the Kalman filter</a>, an estimation framework widely used for its predictive capabilities.</p><h2 dir="ltr">Bibliography</h2><p dir="ltr">Castanedo, Federico. 2013. “A Review of Data Fusion Techniques.”&nbsp;The Scientific World Journal&nbsp;2013, no. 704504 (October): 19. https://doi.org/10.1155/2013/704504.</p><p dir="ltr">Durrant-White, H.F. 1990. “Sensor Models and Multisensor Integration.” In&nbsp;Autonomous Robot Vehicles, 73-89. N.p.: Springer. https://doi.org/10.1007/978-1-4613-8997-2_7.</p><p dir="ltr">Galar, Diego, and Uday Kumar. 2017. “Chapter 1 - Sensors and Data Acquisition.” In eMaintenance: Essential Electronic Tools for Efficiency, 1-72. N.p.: Academic Press. <a href="https://doi.org/10.1016/B978-0-12-811153-6.00001-4" target="_blank">https://doi.org/10.1016/B978-0-12-811153-6.00001-4</a>.</p><p dir="ltr">Lundquist, Christian. "Sensor fusion for automotive applications." PhD diss., Linköping University Electronic Press, 2011</p><p><br></p><p><br></p>

fundamentals

Latest Posts