Innovation Over 50 Years: Focus on the 1970s

It’s hard to believe it’s been 50 years since we opened our doors – but since then we have aimed to be the global leader of innovative audio solutions.

As we celebrate our 50 years in business, we are highlighting our key innovations per decade in five blog posts, starting with the 1970s.

In 1972, Projects Unlimited founded the Audio Products Division and quickly purchased the first electrical buzzers (GA 100) for telephone test sets from Roschi Electronic AG in Switzerland. More innovation in buzzer and indicators followed during the 1970s:

  • 1973: First PCB mounted Buzzer offered
  • 1975: First low frequency panel mounted Indicator offered
  • 1976: First PCB mounted Piezo Indicator
  • 1978: First externally driven Transducer

We are proud of these early innovations and look forward to sharing more with you.

The Advantages of MEMS Microphones

MEMS microphones have several advantages over traditional microphones.Despite their small size–and sometimes because of it!–MEMS Microphones have POWERFUL advantages. 

For example, MEMS microphones utilize a charge pump to produce a constant charge on the diaphragm, resulting in better isolation of the acoustic signal from power supply noise and are not prone to charge decay over time or to sensitivity shifts due to supply voltage changes.

MEMS microphones can recover from moisture condensation since the charge on the diaphragm is renewed by the charge pump once the condensation dries.

They are also less susceptible to vibration and dust because of the construction and smaller diaphragm mass.

The ability to withstand standard lead-free solder profiles (Max Temp 260C for 30s) without impacting performance. Superior temperature performance as sensitivity does not shift with change in temperature (-40⁰C ~ +100⁰C).

Better overall repeatability due to the automated manufacturing process. Multiple mounting options such as top mount, reverse mount or zero height. Custom configurations and mounting options available for seamless integration into the end application. 

Here are some of the greatest advantages, however, and how they might impact you or your product development.

  1. Size Matters: MEMS microphones are incredibly compact, making them suitable for applications where space is limited. They are commonly used in smartphones, tablets, and wearable devices, where miniaturization is critical.
  2. Power Efficiency: These microphones consume minimal power, which is crucial for portable devices with limited battery capacity. This ensures extended battery life for your gadgets.
  3. High-Quality Sound: Despite their small size, MEMS microphones offer impressive audio quality, with excellent sensitivity and signal-to-noise ratios. This makes them ideal for capturing crisp and clear sound.
  4. Durability: MEMS microphones are rugged and less prone to damage from mechanical shock or vibration, making them suitable for harsh environments and industrial applications.

MEMS Microphones are used across industries to solve problems and enhance applications. You can find MEMS technology being used in everything from consumer electronics to health care. 

  1. Consumer Electronics: MEMS microphones have become the go-to choice for smartphones, tablets, and laptops, enabling clear voice calls, noise cancellation, and voice recognition features like Siri and Google Assistant.
  2. Automotive: In the automotive industry, MEMS microphones are used for hands-free calling, in-car entertainment systems, and noise reduction technologies, enhancing the overall driving experience.
  3. Industrial: MEMS microphones find applications in industrial settings, such as monitoring equipment, intercom systems, and security systems, thanks to their durability and reliability.
  4. Health care: In health care, MEMS microphones are employed in hearing aids and medical devices for precise audio detection and recording.

Curious to learn more about MEMS technology? Check out our recent whitepaper on the subject located HERE in our Resource Center or reach out to discuss with one of our engineers. We are always eager to work with our clients to develop the solutions they need to be heard within their industry!

Unveiling the Marvels of MEMS Microphones: A Game-Changer in Sound Technology

In the ever-evolving landscape of technology, MEMS (Micro-Electro-Mechanical Systems) microphones have emerged as a revolutionary force, transforming the way we capture and process sound. These tiny marvels, often overshadowed by their larger counterparts, have silently but significantly altered the audio industry. At PUI Audio, our engineers are working to optimize and enhance MEMS microphones as we continue to innovate solutions for our customers. 

What is MEMS technology?

MEMS microphones, short for Micro-Electro-Mechanical Systems microphones, are cutting-edge audio devices that excel in capturing sound with exceptional precision and clarity. These miniature marvels are revolutionizing the way we experience voice communication and audio recording. With their compact size, energy efficiency, and remarkable sound quality, MEMS microphones are the go-to choice for smartphones, IoT devices, automotive systems, and more.

Whereas the electronic circuits are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the micromechanical components are fabricated  using compatible “micromachining” processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electromechanical devices.

What Are MEMS Microphones?

MEMS microphones are composed of a MEMS sensor and an application specific integrated circuit (ASIC). The sensor includes a pressure sensitive movable diaphragm, perforated stationary plate and a housing.

MEMS microphones are a type of microphone that utilizes microelectromechanical systems technology to convert sound waves into electrical signals. Unlike traditional condenser or dynamic microphones, MEMS microphones are exceptionally small, typically measuring just a few millimeters in size. Despite their diminutive stature, these microphones deliver remarkable audio quality and offer numerous advantages.

The sensor converts incoming sound pressure entered through a sound inlet (top or bottom port) to a capacitance change. The ASIC manages the polarization and generates either a PDM or I2S digital output or an analog output. The diaphragm and the plate act as a variable capacitor and will, under the influence of an acoustic input, produce an AC voltage (the microphone output signal) that is processed by the ASIC.

As technology continues to advance, MEMS microphones are expected to play an even more prominent role in our lives. PUI Audio is continuing to work hand-in-hand with our customers to develop innovative solutions that solve real-world problems. Curious to learn more about MEMS technology? Check out our recent whitepaper on the subject located HERE in our Resource Center or reach out to discuss with one of our engineers. 

PUI has a long history innovating with piezoelectricity

PUI Audio has a long history with piezoelectric components, and while piezo electricity has been a large part of our past, this technology is also a big part of our future. 

We started our innovation journey in 1976 with the industry’s first PCB mounted piezo ceramic audio indicator!

When you combine these terms, a PCB-mounted piezo ceramic audio indicator refers to a component that is designed to be mounted directly on a printed circuit board and is capable of generating audio signals using the piezoelectric properties of ceramics. This component is often used to provide audio feedback or alerts in various electronic devices, ranging from household appliances to industrial equipment and consumer electronics.

Since then, piezotronics have been a big part of the product catalog we offer at PUI Audio, and we are committed to expanding and integrating piezoelectric solutions with audio transducers, benders, microphones, ultrasonic, speakers, haptics product line to meet various application needs.

PUI Audio offers not only buzzers but also sensors and actuators based on piezoelectricity. 

For example, you can find our Simple self driven Piezo Indicators  or our Externally driven Piezo Transducers among our digital product catalog. 

And we continue to innovate!

Our new cutting-edge applications, including piezo haptics and lead-free piezo benders are in development and have launched throughout the year. Lead-free applications and options continue to meet important compliance regulations as they change to phase out lead-inclusive options. Our engineers and product development teams have been working to stay ahead of this curve by developing solutions that do not compromise quality as technology and restrictions change. This work will enable our customers to continue to stay in front of regulations as well. 

Curious to learn more about piezoelectronics? Our engineering team is eager to have a conversation with you and help brainstorm solutions for your latest projects. Reach out, and let’s start a conversation. You can chat with an engineer right here on our website, here. 

Piezoelectric technology continues to push the industry forward

It may surprise you to know that Piezoelectric technology discovered more than 100 years ago is also at the cutting edge of the technology advancements we see today. Just over a hundred years ago by the Curie brothers, Pierre and Jaques, who leveraged the discovery to set in motion the technology that still today is pushing innovation forward, allowing for product engineers to develop new and creative solutions. 

The piezoelectric effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. This unique phenomenon of materials to convert between mechanical and electrical energy continues to be a valuable area of research and innovation.

Today, we see the advantages of this technology play a big role in how engineers create a clear impact within a small space. 

Piezoelectric material can generate a small voltage when subjected to mechanical force, as in the case of sensors like microphones. The reverse piezoelectric effect, where applying a voltage to the material generates physical motion, is a crucial aspect that has been leveraged for applications such as haptic feedback in devices like touchscreens.

In the world of product development, creating a seamless and immersive user experience is a top priority for manufacturers. To achieve this, the integration of cutting-edge technologies is essential, and one such innovation making waves is piezoelectric haptics. Piezoelectric haptic technology, based on the reverse piezoelectric effect, has revolutionized the way products interact with users, offering tactile feedback and a sense of realism like never before.

In consumer electronics, piezoelectric haptics have made significant strides. From smartphones and tablets to gaming controllers and wearables, piezoelectric haptic actuators add a realistic touch to virtual interactions. By providing subtle vibrations during touch interactions, users experience a heightened sense of responsiveness, making their digital experiences feel more natural and engaging.

For instance, in mobile gaming, piezo haptics can simulate the recoil of a gun or the sensation of acceleration in a racing game, creating a more immersive gameplay experience. Similarly, in smartphones, piezoelectric haptic feedback enhances the feel of typing on a virtual keyboard, giving users the sensation of pressing physical keys.

The advantages of using piezoelectric technology is clear, whether that be within our simplest of piezoelectric technologies, the piezo bender, or within our new cutting-edge applications, including piezo haptics and lead-free piezo benders. For more information about piezoelectric technology, check out our Resource Library for our technical whitepaper on the subject, or schedule time to speak with one of our engineers to start brainstorming applications. 

PUI Engineers finding solutions with environmentally-rugged products

As our world becomes more connected and mobile, the demand for audio components that can withstand harsh environmental conditions is on the rise. Engineers are finding new and innovative ways to monitor environments and new needs are arising for components that can withstand extreme weather conditions or have the ability to output high-quality sound in the great outdoors. Environmentally-rugged audio components are becoming increasingly important.

At their core, environmentally-rugged audio components are designed to withstand a variety of environmental conditions, including extreme temperatures, moisture, and vibrations. These components are often used in industries such as aerospace, military, and marine, where ruggedness is crucial for reliable and safe operation.

In recent years, the demand for environmentally-rugged audio components has expanded beyond these traditional industries and into consumer markets, as more and more people seek to enjoy high-quality sound in outdoor and other harsh environments. This has led to the development of rugged audio components that are specifically designed for outdoor environments.

One key feature of environmentally-rugged audio components is their construction. These components are typically built with materials such as high-grade plastics, rubber, and metal, which can withstand exposure to the elements without degrading or failing. Additionally, many environmentally-rugged audio components are sealed to protect against moisture and dust, further increasing their durability.

Another important aspect of environmentally-rugged audio components is their ability to maintain high-quality sound in challenging environments. This requires advanced engineering and design, as well as the use of high-quality components such as speakers, amplifiers, and connectors. Many rugged audio components also include features such as noise-canceling technology, which helps to improve sound quality in noisy environments.

Frozen wind meter device – extreme mountain condition view

As more people seek to enjoy high-quality sound in harsh environmental conditions, environmentally-rugged audio components are becoming increasingly important These components are built to withstand exposure to the elements, and often include advanced engineering and design features to maintain high-quality sound. Whether you’re an engineer, an audio enthusiast, or simply enjoy spending time outdoors, environmentally-rugged audio components can help you develop audio systems that operate to your standards in even the toughest environments.

For more information on environmentally-rugged products at PUI, reach out. Let’s start a discussion about what will work for you. Chat with an engineer today, and we’ll start brainstorming. 

PUI Enhances Focus on Environmentally-Rugged Lines to Withstand the Elements

Audio components can be small, but they can also be fierce, and at PUI, we put special consideration into our environmentally-rugged lines that help engineers and project managers implement audio solutions in conditions that might scare away most technology manufacturers. 

A lot of times, project engineers don’t know what they need when they set out to solve a problem, but our engineers work with clients one-on-one to solve problems with components that can stand up to even the most rugged environmental conditions. 

Because, when it needs to be heard…or measured…or alerted…it doesn’t matter if it is in rain, wind, under water, or in abnormally high temperatures, PUI helps teams to implement the solutions that get the job done, regardless of conditions. 

That’s why we’ve put special focus on environmentally-rugged lines to withstand all the elements, including earth, air, fire or water. That means our components can stand up to rougher weather conditions, no matter which element–or combination of elements could affect the quality of sound. 

Hi-temp components – PUI Audio high-temperature audio speakers and high-temperature audio receivers that can withstand temperatures beyond normal ranges, meaning that components can be placed in areas outdoors or within other components or mechanisms that heat up as part of their everyday use.

Waterproof and water-resistant components – Audio components are being deployed within industries where components may need to be submerged partially or underwater full time in order to measure, record or alert. Industrial settings are using audio components to measure flow and water levels, and while this is an innovative use of components beyond typical use, components must also be able to withstand the rigors of wet conditions. 

High-definition components – PUI Audio has made significant strides in the use of high-definition audio components, and while at first glance, this might not seem like part of our environmentally-rugged lines, think about how weather conditions like wind or earth, mountains, valleys, foliage and other types of interference could affect the quality of sound. High definition components are able to zero in or extract specific sounds in ways that no other components can, removing obstacles, such as the naturally-occurring environment from being a hurdle to success. 

PUI Audio components are designed thoughtfully to fit into whatever project you are working on, so the best solution is always in reach. Some of our best solutions come from conversations with clients who don’t know what they need, but help our engineers paint a better picture of what they are up against. The more information we have up front, the better and easier it is to identify which types of environmentally-rugged components are needed to complete a project. 

That’s why we always work with engineers and project managers from the beginning to make sure we identify potential problems up front and select components that keep projects and audio clean. We pride ourselves on offering “audio enhanced with expertise,” which means you can count on us to identify the problems–and solve them–before your project even starts. 

Look for more information about our environmentally-rugged lines on the PUI website. Browse products, discuss solutions and explore our resources for deeper dives into the potential of innovative audio solutions. 

Innovations in ultrasound are pushing PUI Audio customers into new territory

Our tagline at PUI is When it needs to be heard. What happens, though, when it can’t be heard, but needs to work anyway?

Our engineers are immersing themselves in new products that tap into the capabilities of ultrasonic transmissions for the purpose of using audio in new and innovative ways. Ultrasonic makes for a challenging design because the output can’t be heard at normal frequencies, but the possibilities are limitless. 

Think about bats. Bats use ultrasonic transmissions to feel the world around them with exact accuracy. The animals produce ultrasonic sound waves and those sound waves bounce off objects in their environment. Then, the sounds return to the bats’ ears, which are finely tuned to recognize their own unique calls and provide the data to map the environment around them. 

Similarly, PUI engineers are helping our customers develop audio systems for real-world solutions to mapping the environment in useful and actionable ways.

One example is found in the auto industry, where ultrasonic sensors are used for moving vehicle backup alarms, letting drivers know what is behind them and when it is too close. 

Ultrasonic audio components are also used in industrial settings, helping to provide actionable measurements. PUI Audio customers are using the technology in new ways and pushing the technology forward. For example, one customer is using ultrasonic to measure the fill levels in dumpsters, while another is using it to measure flow and speed of water through pipes. 

The use of ultrasonic components helps provide not only the accurate measurements, but also the ability to measure through ongoing adaptable analytics that provide real-time changes and historical data.  

The science isn’t new, but the technological applications are, and PUI Audio is still exploring all the ways the science can be applied in industrial, medical and consumer settings. It’s a new frontier, and as with most of the new frontiers PUI is working to break through, the best ideas come through collaboration and brainstorming with our customers. Often, we don’t know where the solutions will lead us until we start talking, so if you have an idea, question or rogue thought and are wondering if ultrasonic might provide the answer, let’s talk!

Have a conversation with an engineer, and let’s figure it out together.

Three Unique Ways Our Clients are Using Microphones to Collect More Than Voices

Microphones aren’t just for voice collection. Here’s three unique ways engineers are putting microphones to use in creative ways to collect data and solve problems. 

  1. Microphones are being used in nature. 

Scientists are developing creative ways to use microphones in the collection of audio as it relates to nature, habitats and environmental protection and sustainability. PUI Audio has worked with some scientists as they’ve set up audio collection points in wilderness areas to collect audio for the detection of certain species, so they can track habitat populations and migratory patterns. Additionally, microphones are being used in nature to collect ambient sounds for use in electronics and soothing sounds to help people sleep!

Microphones are being used in nature to collect ambient sounds for use in electronics and soothing sounds to help people sleep.
  1. Water leak detection and flow rate

PUI Audio has seen some creative uses for audio components, and one way in which we see out water-resistant microphones being used is in the collection of audio for the purpose of detecting minute sounds as they relate to water. Through the use of sensitive and water-resistant microphones, we are seeing teams use microphones to detect water leaks, track flow rate and study the movement of water through specific spaces. 

  1. Security and gunshot detection

Another way microphones are being deployed is as a security measure. Microphones can detect via sound the presence of unwanted visitors and even gunshots. With highly-sensitive microphone equipment, we are seeing that our microphones have been used to zero in on the specific sound of gunshots or other noises indicative of a safety breach (like broken glass), and helping alert authorities for quicker response times. 

Many people think of voice when they think of our microphone product category, but these are just three ways we are watching creative and innovative teams think about audio differently, deploying microphones to solve and proactively gather information. Every year, we are helping our clients brainstorm new and unique ways to study and collect audio and continue to push the industry forward.

What you need to know before choosing the right microphone for your project

When it needs to be heard, PUI Audio microphones help to capture clean sound in ways that make your projects effective, whether you are capturing voice or using microphones for audio detection in other ways. 

When deciding on a microphone as a component of your engineering project, you have some key decisions to make for what microphone is right for your needs. 


The sensitivity of your microphone will determine how well it picks up on the sound around it. If you are looking to capture voice, you may not need as highly sensitive a microphone as if you were looking to capture and detect specific sounds among ambient noise, for example. A voice would be spoken directly into the microphone, so the microphone wouldn’t need to be as sensitive to pick it up. However, if you were a researcher attempting to capture the sounds of a specific bird in an area of wilderness, you will probably need a microphone that can zero in and pick up that specific sound. 


When thinking about the directivity of your microphone, you need to consider where the noise is in relation to the microphone components of your project. 

  • Uni- A traditional unidirectional microphone will pick up sound from one primary direction, generally in front of the microphone. 
  • Bi- A bi-directional microphone will pick up sound in two directions, but it isn’t as black and white as thinking of a microphone as if it has an x and y axis. Instead, the microphone picks up sound in a more circular or spherical shape around the microphone, so a bi-drectional microphone will get you pretty close to picking up sounds in all directions and cover the majority of space around the microphone. 
  • Omni- An omni directional microphone will cover all of the gaps missed in a bi-drectional microphone. The sound is collected in all directions, and will cover the most area of any of the microphone directivity types. 

Special Features

When considering your microphone type, you also need to consider what special features you may need to execute your project to your specifications. 

PUI’s line of HD microphones are making a major impact across industries by picking up sound in a crisp and clear way that rivals the sound quality of larger, more expensive and more robust units. From a small package, the sound quality captured in our high definition microphones is amazing audio engineers across the industry. 

Water resistance and high-temp options:

Where will the microphone need to be placed? 

If your microphone will need to withstand the elements, consider looking at PUI Audio’s high-temperature microphones or water resistant microphone options. Our components are quality tested to withstand the additional strains of these types of elements without compromising audio quality and collection. 

Whatever your needs for audio quality and collection, PUI Audio can help you to find the right microphone and audio components for your project. The difference is our engineering team. We are eager to brainstorm creative solutions with you and develop solutions that will help your project succeed. Reach out and chat with us to learn more about how we can help. 

What’s the buzz about feedback you can feel? Three ways PUI’s new haptics can improve accessibility in medical and industrial settings

Haptics are buzzing at PUI Audio as we are heading into 2023 thinking of audio as a full sensory experience. 

Last year, PUI introduced a new line of products, focused on the tactile experience. The new haptics products provide feedback you can feel using the same electromagnetic principles as a speaker – but instead of a paper cone moving air, a moving mass is used to deliver vibrations.

Our haptics products are working to make the world a safer, healthier and more accessible place. 


In medical and industrial settings, the ability to feel an important alert is sometimes just as important as hearing one. And when we think of our hearing impaired end users, the ability to feel an alert is even more important. 

Haptics help in a crowded medical alert environment.

When multiple notifications—or alerts–are alarming at once, it can be difficult to hear or discern when an alarm is ringing, and then to hear quickly which alarm is ringing. The added practical applications of haptics in a medical setting ensure that alerts are felt and information is deciphered quickly.

Additionally, when commands are input, the addition of haptics, and tactile feedback, make it easy to confirm when the right buttons have been pressed or data input into a system. The additional feel of confirmations (or rejections) through haptics, provide an added layer of support to health care workers who are having to untangle many messages at once. 

Haptics help in a crowded medical alert environment.

Utilizing multiple senses helps messages be delivered. 

The human body’s five senses are the pathways through which we experience the world around us. It is exceedingly rare that any of these senses are experienced in isolation; often, two or more of our senses receive information simultaneously. Traditionally, many products use two of the five senses to deliver information to a user–sight and hearing. The same strategy applies to haptics, which add a tactile notification in addition to audible or visual cues. 

Think about settings in which you push a button and see a light light up, or a beep to confirm. These alerts are enhanced with you also feel the confirmation, with a vibration, indicating to your brain the the process was successful. 

Safety messages are heard–and felt–quickly and directly.

In an industrial environment, operators rely on this tactile feedback to prevent accidents, ensure safety and confirm successful processes. 

Think of a forklift operator, who is using their visual sense to pay keen attention to the task in front of (and behind them). The operator relies on memory, or tactile feedback, to ensure things they cannot look at are successfully changed or implemented, like buttons being pressed. 

The same can be true of those working on a production line, or operating heavy machinery. Often, visual senses must be activated to look in or at a certain focal point, leaving the operations exposed to trusting that other supplementary processes are functioning, confirmed, or—in the case of a safety issue, that the operator is alerted in a way that doesn’t detract from other key functions, where eyes and ears are needed. 

Haptics have many applications. Medical and industrial settings are just a couple of examples of how implementation of tactile feedback can help keep critical operations safe. The addition of tactile feedback provides more than accessibility, vibrations ensure messages are relayed in multi-sensory ways that keep operations efficient, medical settings moving and industrial settings safe. 

Learn more about what PUI is doing with haptics in our resource center.