InControl Medical, located in Wisconsin, is a medial equipment company offering solutions for female urinary incontinence, a common problem among women, particularly after childbirth. At least 20% of the female population in the United States experiences this problem. Previous offerings to solve this health problem were uncomfortable, yielding poor results that often lead to invasive surgery to correct the pelvic floor.

In response to this problem, InControl Medical created InTone, which combines electrical muscle stimulation and biofeedback to create a non-invasive home-use solution offering more comfort, better tracking, and thus improved results for patients. The patented probe, shown below, contains a small pressure sensor that measures the change in pressure inside the probe when the muscle contracts against it. This data is tracked in the handheld control unit that acts as a portable therapist, guiding the patient with visual and audible instructions to ensure exercises are done correctly. Precise gains in pelvic floor muscle strength are documented in one one-hundredth of a pound per square inch. Each session is date stamped and weekly averages are calculated to compare against previous weeks, thus allowing health care providers to follow the patient's progress.

About the pressure sensor

When selecting a pressure sensor, InControl turned to Servoflo to assist in finding a solution. After evaluating their application requirements, Servoflo suggested trying the SLP33A Pressure Sensor Series, a high performing gauge pressure sensor with a 0-2 psi range and a linear 0.5 to 4.5 volt output. Because the temperature range in the application is narrow, InControl is able to optimize the output resolution and accuracy to provide data to one one-hundredth of a pound per square inch. This pressure sensor also accepts a low power supply of 2.2V to 3.3V and a small size of 10 mm X 8.6 mm, making it a perfect fit for portable medical applications. The pressure sensor is available as a 6 pin dual-in-line package or surface-mount. The high performance combined with low cost made it an ideal choice for InControl Medical. Obtain detailed specifications about the SLP33A pressure sensors.

To learn more about InControl Medical, please visit their website at www.incontrolmedical.com.

To learn more about pressure sensing solutions from Servoflo, please visit www.servoflo.com. Servoflo is a provider of pressure sensors, humidity sensors, sensor signal conditioners, and LED drivers for the medical, process control, HVAC, automotive and other industrial applications. 

When designing a new product, looking for components can be daunting. Often times, designers must decide whether to purchase an off-the-shelf pressure sensor or design their own. This post helps clarify the criteria designers can apply when making this important decision.

• What do I need from the total SYSTEM perspective? Look at the overall product by reviewing total performance requirements, the market and applications. How does this affect component selection?
• How quickly will begin sellingyour product?
• What skills do you have within your organization? What skills do you need to outsource? For example, do you have electrical and mechanical engineering skills residing within your organization? If you do, are they accessible and available for design assistance? If you need to look elsewhere, do you have a qualified resource to utilize?
• Do you have the equipment necessary to calibrate your own transducer? Typical equipment needed are temperature, pressure and humidity tools to modify the environment for calibration. Are there people available to calibrate your designed sensor?
• There are additional logistical issues to consider. For instance, what is your annual requirement of sensors? What is your time-to-market and cost targets? Where are you manufacturing? Are there any proprietary issues to consider? How many sources do you need?

By reviewing these questions, the path to deciding between make versus buy becomes much clearer. You should buy a complete transducer if you are resource-limited and have a fast-time to market requirement. Lower volumes typically under 25,000 sensors per year do not usually warrant the investment in making your own transducer. Above this quantity, return on investment on internal resources is improved and may be something to consider.

Let's take a look at a specific example by evaluating the following situation. 

An application has a requirement for a calibrated, temperature-compensated pressure sensor that measures up to 30 psi. An amplified, off the shelf solution has a cost of between $6-7 each at 1,000 pieces, with a 1.5% to 1.8% accuracy over a broad temperature range. A fully packaged solution also translates into fewer parts to buy and stock.

To create the same transducer internally, the cost of an unamplified, uncalibrated pressure sensor plus additional op amps and signal conditioning to calibrate for span and off-set would cost in parts approximately $2-3, not including assembly labor and calibration time. Perhaps your accuracy requirements are not as stringent as 1.8% over a wide temperature range or there are packaging issues to consider. Another consideration to think about, if you are utilizing a contract manufacturer, there are typically assembly charges per component so the additional insertion of perhaps 6 components could affect assembly costs.

If your volumes are very high, investment in automated, more sophisticated calibration equipment can reduce labor time and costs and have an attractive return on investment.

Our team of experts combined with a broad selection of pressure sensors (both unamplified and fully packaged) and signal conditioning parts can guide you through this process. Our huge offering ensures that a solution can be found for you, regardless if you make or buy.

To get started, the best use of your time is to take advantage of the Sensor Selection Tool. We can then provide you with informed, detailed options for your consideration at no obligation to you. We view our role as a design resource to find you an optimal solution for your design.

Access the Sensor Selector Tool here

Review our Transducer Design Guide which includes typically sensor elements and signal conditioning for making your own pressure transducer.

We recently read a press release by a research company discussing pressure sensors and MEMS. We found the article to be very interesting and thought we would share some key points:

• Pressure sensors generated $1.22 billion in revenue mostly driven by a strong automotive industry recovery, up 26% from 2009.
• By 2014, revenue for MEMS pressure sensors will be $1.85 billion.
• Automotive sector remains the largest area for MEMS pressure sensors at 72%, followed by medical electronics at 11%. The remaining area is general industrial and consumer electronics.

Automotive applications primarily reside in manifold air pressure sensors and a growing area in transmission systems. The most popular medical application involves low cost disposable devices for catheters used during surgical procedures, with additional growth in CPAC (continuous positive airway pressure) for sleep apnea.

Industrial applications are primarily in the HVAC sector, level measurements, and various industrial process and control applications. Consumer applications include weather stations, sports watches, bike computers, dive equipment, pedometer and white goods.

As a provider of MEMS pressure sensors that can work for all of the above mentioned applications, we were, of course, pleased to see forecasted growth. We have seen pressure sensor designs make tremendous gains in performance, calibration ranges, and reduced size. Product designers have a wide range of pressure sensors to choose from.

We are curious to know what you think of this predicted growth? Drop us a comment and let's talk.

See the following application pages to review MEMS pressure sensors offer by Servoflo:

Automotive

Medical

HVAC

Servoflo has posted a new paper written by Dr. Norbert Rauch, a well-respected sensor engineer in Germany. His paper, titled "The 24-bit Revolution in Pressure Sensor Technology", discusses how altitude can be accurately measured with the impressive resolution provided in the MS5607 silicon-based pressure sensor, which uses the latest 24-bit ADC technology.

Most traditional altimeter sensors have resolution of several meters, making them not very precise. These traditional sensors have a digital signal conditioning unit and operate on a 14-bit ADC. However, a 14-bit ADC does not automatically mean that the signal can be resolved with 14 bits. Depending on the signal span, offset, and the signal evaluation electronics, possibly 10-12 bits are available for signal conditioning. Until now, achieving a better level of resolution was only achievable with a complex pressure sensing system which is costly and difficult to achieve.

The paper discusses how the MS5607 eliminates these problems with the use of an ASIC and MEMS technology. By taking into consideration that resolution must not be confused with precision, calibration accuracy and offset drift due to temperature changes must also be considered when assessing solutions. Physical size and power consumption are also factors for designers.

The paper will educate readers on how to better understand the importance of the 24-bit designs and implications for applications.

We have updated our medical applications area with the latest pressure sensor products. The goal of this section is to provide you with a quick and easy way to find sensors by application. Pressure sensors are becoming increasingly important in medical equipment. The latest technologies available give designers flexibility in how sensors are used. Lower tolerance sensors combined with sensor signal conditioning lets medical equipment designers choose more cost effective solutions while tailoring a sensor to their specific needs.
View your specific medical application here:
Blood pressure measurement
Breath detection
Inflatable mattresses
Infusion pumps
Deep vein thrombosis
Oxygen concentrators/conservers
Within each of these product areas are specific pressure sensors appropriate for that application. If you do not see a product that fits your needs, please feel free to contact us about your specific application requirements. We have access to additional pressure sensors and transducers that are not on our web site. Our extensive knowledge in the medical market gives you expert access to what are the most important sensor features needed.

If you have a story to share about your experience with pressure sensors in the medical market - problems, solutions, things to watch out for, please feel free to post them here.