What Is a Key Fob?

A key fob is the small handheld remote control device that controls a remote keyless entry system. When you press the button on your keys and hear the comforting chirp of your car’s unlocking mechanism, you can thank the humble but mighty key fob. But there’s a lot more to key fob technology than you might realize. 

Key fobs are the perfect example of a technology that many people use constantly but don’t give much thought to. These tiny handheld devices have been revolutionary for the development of remote keyless entry systems, automotive and otherwise, and all it takes is a few minutes of losing yours to realize how important key fobs are for many people’s lifestyles. 

What is a key fob? In today’s TechTalk article, we’ll look more deeply into that question, and we’ll talk about the many aspects of key fobs you might not have been aware of. We’ll also discuss why key fob cases are an important part of an RFID key fob system and how to choose the right one when you’re building a device or secure access system that requires a handheld remote control. 

What Is a Key Fob? Basic Concepts to Know

Here are five of the basic principles that define key fobs as they’re designed, manufactured and used today: 

1. A key fob is a tiny remote control with an RFID chip and an antenna inside. It uses radio frequencies to communicate with another RFID tag inside a reader device, which is attached to a locking system. Each key fob chip is designed to transmit specific RFID tag information that matches what the reader device has been programmed to accept. 
2. When a user presses the button, the key fob transmits an RFID signal to the reader device. If the RFID information transmitted from the key fob matches what the reader is programmed to accept, the system will open the door. 
3. RFID key fobs are highly versatile and can be programmed to transmit a number of different commands. Usually, these include functions such as opening a specific door or starting an engine. Most automotive key fob units have multiple functions assigned to different buttons. 
4. The typical key fob is contained within a plastic enclosure small enough to hold in your hand. Some key fobs are basically badges that only need to be passed in front of an electronic lock to open it. Other key fobs contain one or more buttons that transmit specific RFID signals. Each button performs a different function–like locking the vehicle, unlocking the vehicle or opening the trunk. 
5. Key fobs are most commonly used today in remote keyless entry systems for automobiles. However, the technology actually has much wider applications (which we’ll discuss below). That versatility stems from the many inherent advantages that key fob devices offer. 

See our guide to how key fobs work for more information on the inner workings of a remote key fob. 

The next question: Why have key fobs become such a ubiquitous technology in our world? The answer lies in the numerous advantages that they offer for all kinds of systems. 

Advantages of a Key Fob

There are several advantages to using a key fob system, whether for an automobile or for a different application. Among the most important advantages of key fobs are: 

• Reliability: Copied keys can be unreliable, particularly if they’ve been made using substandard materials or equipment. A high-quality RFID chip is a reliable and long-lasting solution. 
• Security: Physical keys can be lost and copied to gain unauthorized access, but a misplaced key fob can be deactivated remotely. 
• Reprogramming: It’s easy to reprogram key fobs and locks when a fob is misplaced, replacing the expense and hassle of physically replacing locks. 
• Convenience: Key fobs make it incredibly fast and easy to unlock a vehicle or anything else with an electronic lock system. They can also make everyday tasks easier for people with disabilities that make it hard to turn a physical key. 
• Size: Multi-button key fobs offer an easy way to consolidate numerous functions into a small and highly portable package. 
• Access Levels: Key fobs can be customized to provide access only to certain areas, which makes them excellent for applications that require restricted access. 
• Battery: Some key fob devices (called passive key fobs) have no need for a battery because they are powered by the magnetic energy transmitted between the antenna and the reader. Many of today’s key fobs do use a battery, but these watch cell-style batteries last a long time before needing to be changed. 

The advantages that a key fob offers have driven its increasingly widespread adoption and advanced development. But it took some time for the device to acquire its current form. 

History of the Key Fob

The use of the word “fob” for a small handheld tag began in the late 1800s with the advent of the “watch fob.” Back in the days when pocket watches were a common accessory, a watch fob was a small ribbon, chain or ornament that was attached to a pocket watch. The word “fob” was likely derived from the German fuppe, meaning “pocket.” 

Before key fobs were an electronic device, they were another word for decorative keychains throughout the 20th century. If you mentioned a “key fob” to a person in 1960, they would likely imagine a small trinket attached to a set of keys—perhaps a sports team logo or a favorite miniature photograph. The modern-day key fob gets its name from this older definition.

“Key fob” gained a new definition when remote keyless entry systems first became widely available in American cars during the late ’80s and early ’90s. Early models of remote keyless systems used infrared waves, but these had major disadvantages such as requiring an uninterrupted line of sight and being easy to intercept. RFID eventually became the predominant technology due to its improved security and reliability. 

Keyless systems today often include many advanced features. Some activate a powered lift gate feature that lifts the door of the vehicle’s rear hatch—perfect for shoppers arriving with a heavy load of groceries. Others can even start the vehicle’s engine remotely, which is ideal for warming up your vehicle on a cold day. 

Others Uses for Key Fobs

A key fob can serve many other purposes besides controlling vehicle systems. Any time that a system needs a convenient handheld control method, a key fob can be a great choice. That’s because multiple key fobs can be programmed to correspond with the same reader through what’s called an open-access platform. 

One common application for open-access key fobs is creating secure access systems for buildings without requiring the use of physical keys. Not only are physical keys a potential security risk, they’re also cumbersome to carry around if numerous discrete points of access are necessary. Instead, an apartment building owner (for example) could create tenant key fobs that access a single unit and common areas without providing access to other units or restricted areas. 

Key fobs are also a great way to create controlled access in commercial and industrial facilities. Using backend software that controls all connected RFID readers from a common server, facility administrators can program key fobs remotely and create multiple levels of access. This is a great solution in facility types ranging from factories to hospitals. 

Small household devices that need a remote control, such as garage door openers, are another popular application for remote key fobs. The convenient, pocket-sized nature of key fob enclosures makes them ideal for these everyday applications, and their security features help keep homes safer. 

Key Fob Security

It’s crucial that the manufacturers of any wireless remote device take the steps to ensure the device is secure. While wireless RFID key fobs are in general more secure than physical keys, they can still be vulnerable to certain exploits when not properly secured. Thieves have unfortunately been able to use these tactics to steal cars, break into houses and commit other crimes. 

Today’s key fobs include many security features to prevent their signals from being intercepted and copied. Most key fobs use pseudo-random sequence generators to transmit a unique unlock sequence every time. Because the key fob’s RFID system is keyed to the same sequence, the new code will activate the lock, but an old code captured and reproduced from it won’t. 

If security is a top concern for your key fob application, it’s easy to add extra measures to keep your key fobs more secure. For example, some key fob systems keep a permanent record of which fobs have been used to enter and when they were used. It’s also easy to change locks when necessary. Rather than having to have the lock physically re-keyed, it can be reprogrammed to change its authentication procedures. 

What to Look for in a Key Fob Enclosure

When searching for the right key fob enclosure, what are the criteria that you should be sure to look for? Here are some important factors to consider: 

• Form Factor: Key fob enclosures should have a compact design that’s easy to hold in the hand but still big enough to hold any required components. 
• Complete Solutions: Key fob enclosures should be available with all necessary hardware, including buttons to operate the device and screws to hold it together. 
• PCB Support: Key fob enclosures should accommodate a printed circuit board (PCB) of the size that your application requires. 
• Durability: Key fob enclosures should be made from durable materials that will stand up to being repeatedly handled and potentially dropped. 
• Cost: Key fob enclosures should be available at an affordable price point, especially if you have to create large numbers of key fobs. 
• Design Aesthetics: Key fob enclosures should have a design that matches the aesthetic profile of your application. 

Next, we’ll look at some key fob enclosures from Polycase that are designed with these characteristics in mind. 

Key Fob Enclosures from Polycase

Polycase offers our FB Series key fob enclosures for our customers who need the perfect key fob enclosure. We’ve designed these enclosures to be a perfect fit for many different wireless remote control applications. The FB Series is built with high-performance features such as:

• ABS Plastic Construction: FB Series key fob enclosures are made from ABS plastic, a hard and durable material that’s long-lasting and resists rough handling. 
• Molded Key Ring: A key ring is molded directly into the enclosure to allow for easy attachment to a standard key ring. 
• Built-In Buttons: FB Series key fob enclosure models are a turn-key solution (no pun intended) that include all necessary parts of the button and enclosure assembly.  
• Multiple Button Options: Most FB Series models are available with anywhere from zero to five buttons. 
• User-Friendly Design: The simple snap-together and screw-together designs of FB Series enclosures make the enclosures easy to assemble. 
• Designed for a PCB: Since most key fobs use PCBs inside, FB Series are designed as PCB enclosures that hold a PCB securely and easily. 
• Optional Battery Holder: FB Series enclosures are available with an optional snap-in coin cell battery holder designed to fit the coin cell batteries commonly used in key fob devices. 

We also make it a snap to customize your key fob enclosure with custom digital printing and CNC machining cutouts. Print your key fob enclosure with high-quality graphics for branding or instructional purposes, and create any extra cutouts you need cleanly and precisely using state-of-the-art CNC machining. 

Polycase FB-45 Plastic Key Fob Enclosure 

(shown with optional five-button configuration)

Polycase makes it a snap to get the high-quality key fob enclosure that you need. More questions? Just call our electrical enclosure professionals at 1-800-248-1233 or contact us online. We’ll be glad to assist with whatever you need. 

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