How Does a MEMS Sensor Work?

MEMS Sensor Technology

MEMS inclinometers and accelerometers are low-cost, high-precision inertial sensors that serve a wide variety of industrial applications.

A MEMS (micro-electromechanical system) is a miniature machine that has both mechanical and electronic components. MEMS are made up of components between 1 and 100 micrometers in size (i.e., 0.001 to 0.1 mm), and MEMS devices generally range in size from 20 micrometers to a millimeter (i.e., 0.02 to 1.0 mm). A MEMS sensor, for example, usually consists of a central unit IC or microprocessor and several components that interact with the surroundings such as mechanical components making up a complete sensor. The term

MEMS is used to describe both a category of micro-mechatronic devices and the processes used when manufacturing them. Some MEMS do not even have mechanical parts, however, they are called MEMS because they miniaturize structures used in conventional machinery, such as springs, channels, cavities, holes and membranes. Because some MEMS devices convert a measured mechanical signal into an electrical or optical signal, they may also be referred to as MEMS sensors.

How Does It Work?

MEMS Sensors are composed of a suspended mass between a pair of capacitive plates. When tilt is applied to the sensor, the suspended mass creates a difference in electric potential. The difference is measured as a change in capacitance.

Sensor manufacturers will select a MEMS sensor chip, usually based on the level of sensitivity and other specifications and incorporate them into their own electrical design. These MEMS sensors are part of a complete printed circuit board design that will offer specific inputs, outputs, filtering, signal processing, and the ability to store or change temperature coefficients. They are then mounted in some type of housing with connector, and accurately zeroed and tested. In other words, sensor manufacturers will select a low-cost MEMS chip and build a more robust, better performing rugged sensor for a range of Industrial, Rail, Oil & Gas, Solar & Wind, Bridge Monitoring, and even some Aerospace and Military applications, and will range in price depending on accuracy, resolution and other performance specifications.

The greatest resolution you can get with a MEMS inclinometer is 0.0001° (JDI series). That’s a different story from the highly accurate electrolytic line. This line’s most sensitive tiltmeter (A603 tiltmeter) boasts a 2.5 nanoradian resolution. However, MEMS has some advantages of its own.

A MEMS sensor provides the convenient features available with any other sensor line. They have IP65, or even IP67 seals and since the operating temperature range is -40° to +85°C, they will withstand some intense conditions. While Force Balance and Electrolytic sensors have much higher accuracy, some of them can be sensitive to temperature.

These sensors are great solutions to applications that do not demand the highest accuracy such as industrial automation, platform leveling, position control, and pitch and roll measurement. Since they are low cost, you can even save some dough on your next big project!

In April 2015, Jewell Instruments launched its MEMS accelerometer and inclinometer product lines. Now that the company encompasses force balanced, electrolytic and MEMS technologies, there are very few tilt applications that a Jewell sensor cannot serve.

Later, Jewell Instruments changed the game when we unveiled the single or dual-axis JDI-100/200 MEMS inclinometer. This low-cost MEMS sensor is the first to feature full temperature compensation across operating temperatures from -30° to +60°C with 0.004° relative accuracy, ±1° to ±60° measuring ranges, and 0.0001° digital resolution. It is also RoHS compliant to satisfy environmental standards. The super-sensitive JDI series now includes additional output and connector options, including wired, 8-pin, and dual Deutsch connectors. In addition to ASCII RS-485, the JDI now offers ASCII RS-232 and MODBUS RS-485 digital outputs. This positions Jewell’s flagship product as the most versatile digital tilt sensor for numerous applications.

MEMS Sensor Technology is the most cost effective for industrial applications and has many technical advantages of its own. They can also handle high frequency environments. If you have space constraints, the MEMS utilizes very compact micro machine components so that each sensor can fit into the palm of your hand. These sensors are fine solutions to applications that do not demand the highest accuracy such as industrial automation, platform leveling, position control and pitch and roll measurement. Some of the main advantages are:

  • Lower cost compared to other technologies.
  • Wide range (up to +/-90 deg., +/-40G)
  • Dynamic response with bandwidth up to 725 Hz
  • Smaller footprint
  • Requiring less input power to operate
  • Some are fully temperature compensated devices for accurate measurements when temp variation is a factor.
  • Faster lead time due to expedited manufacturing processes
  • Some offer many termination options available.
  • Analog (±5V, 0-5V), current (4-20mA) and digital (ASCII RS232, ASCII RS485, TTL and Modbus RS485) output signals

How To Select The Right MEMS Inertial Sensor For Your Project?

In this world of doing more with less, MEMS sensors can be the solution for plenty of industrial projects, not just cell phones. MEMS sensors are a lower-cost solution as opposed to traditional, higher precision sensors. For applications that require high volume and lower precision, such as construction machines, MEMS sensors will fit in just fine. MEMS sensors offer a wider range (up to ±90º, ±40G) and dynamic response up to 725Hz, which is useful for some vibration measurements. With a resolution up to 0.0005º, some MEMS sensors are catching up to traditional, higher precision sensors.

Jewell Instruments is a world leader in the manufacture and distribution of acceleration and tilt sensors that utilize force-balanced, MEMS, and electrolytic technology. We provide custom solutions for a diverse group of markets, including industrial automation, OEM, rail, aerospace, military, geophysical/geotechnical, and many more. Our experienced engineering team works with customers to produce high-quality, reliable products that meet or exceed all customer requirements.

For industrial applications, this low-cost alternative is an asset. The resolution of MEMS models does not quite compare to that of a Forced Balance or Electrolytic sensor, but for many applications, that’s okay. For OEM applications such as cranes or combiners, you won’t need the accuracy of a sensor that has the precision for leveling a railroad or monitoring sediment (although some MEMS models can reach a resolution of up to 0.0005º). The option of MEMS offers the precision necessary for these industrial projects without taking a hefty bite out of the budget.

It’s no question that MEMS can be used for plenty of OEM applications such as construction equipment, agricultural machinery, or platform leveling, but they can be used for testing applications too. With a bandwidth up to 725 Hz, users have found MEMS accelerometers to be useful for vibration sensing conditions such as automotive testing or monitoring the pitch and roll of an aircraft. The recently expanded MEMS line includes excellent options such as the JDI series which now offers six different connection options. In addition to the original DB9 Connector, you can now purchase the JDI with an M12 connector, making it perfect for harsh environments that require a rugged connection such as construction, weapon platform leveling, equipment for the aerospace industry, and structural monitoring to mention a few. Choose a C06 circular connector for quick & robust connection. If your application calls for a wired connection, Jewell is prepared to offer not one but three wired options: Flying Leads, Deutsch, and Double Deutsch. The improvements did not stop there, though. We added new digital interface options for maximum versatility.

Product Selection

MEMS sensors have matured to serve not just cell phones anymore. The industrial market, including construction and agricultural OEMs, can implement a MEMS-based sensor into their machinery. The sensor can measure and control the positioning of the machine’s tools for optimum performance. They can also be used for platform leveling for mobile cranes and radar as well as testing in the laboratory or classroom. If you’re still looking for a tilt or motion solution for your project, talk to our sensor experts. Our knowledgeable engineers are ready to help you choose the sensor that is right for you. With so many options to choose from, you are sure to find a MEMS sensor that perfectly suits your application.

Number of AxesOutput SignalResolution (mg) (up to)Max range (g)Bandwidth (Hz) up to
JMA-100/200/3001,2,3voltage, current0.025±10200
AKA-3003voltage, current1±40725
Number of AxesOutput SignalResolution (deg) (up to)Max range (deg)Bandwidth (Hz) up to
JMI-100/2001,2voltage, current0.002±905
AMI1,2voltage, current0.001±3050
AMH1,2voltage, current0.001±6020
AMS1,2voltage, current0.01±9020
AML1,2voltage, current0.05±9020
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