Piezo Film Elements

Piezo Film elements are offered in four variations:

• Silver ink screen printed electrodes
• Lamination for higher voltage output when bending
• Flexible leads
• Shielded sensors

Applications include:

• Dynamic strain gauges
• Vibration sensors for alarms, switches, speakers, and contact microphones

Piezo film design kits are a good starting point to learn more about Piezo film sensors and their applications.

CM-01B

Applications: Electronic stethoscope, Bone-conducted sound pickup, general purpose contact microphone, Vibration/Impact sensing

Industries: Medical

Datasheet: Contact_Microphone

Description: The CM-01B Contact Microphone uses sensitive but robust PVDF piezo film combined with a low-noise electronic preamplifier to provide a unique sound or vibration pickup with buffered output. The design minimizes external acoustic noise while offering extremely high sensitivity to vibration applied to the central rubber pad. The CM-01B is ideal for detecting body sounds.

Features:

• Robust
• Low Noise
• Piezo Film Technology
• Shielded Cable
• Broad Bandwidth
• High Sensitivity
• Excellent Impact Resistance
• Lightweight
• Low Cost

DT_Series

Applications: Contact microphone, Dynamic strain gages, Speakers, Switches

Datasheet: DT_Series

Description: The DT Series of piezo film sensors elements are rectangular elements of piezo film with silver ink screen printed electrodes. They are available in a variety of different sizes and thicknesses. The DT film element produces more than 10 millivolts per microstrain, about 60 dB higher than the voltage output of a foil strain gage. The capacitance is proportional to the area and inversely proportional to the thickness of the element. The DT series sensors are the simplest form of piezo film sensors, used primarily as dynamic strain gages and contact microphones for vibration or impact detection. These are available without any leads for those applications where the customer wants to make his own lead attachment. They can be readily adhered to a surface with double-sided tape or epoxy. Lead attachment can be achieved by compressive clamping, crimps, eyelets, conductive epoxy or low temperature solders. DT elements are supplied with a thin urethane coating over the active sensor area; the lead attachment legs are free of the insulating urethane coating.

Features:
• Available in a variety of different sizes and thicknesses
• Produces more than 10 millivolts per microstrain.
• Simplest form of piezo film sensors
• Readily adhered to a surface with double-sided tape or epoxy

DT Series Lead Attachments

Applications: Contact microphone, Dynamic strain gages, Speakers, Switches

Industries: Medical, General Industry, Consumer Goods

Datasheet: DT_Series_LeadAttach

Description: The DT Series of piezo film sensors elements are rectangular elements of piezo film with silver ink screen printed electrodes. They are available in a variety of different sizes and thicknesses. Lead attachment is accomplished using a riveted lug going to 12” (300 mm) of 28 AWG wire. The DT film element produces more then 10 millivolts per micro-strain. The capacitance is proportional to the area and inversely proportional to the thickness of the element. The DT elements are supplied with a thin urethane coating over the active electrode area to prevent oxidation to the top surface of the silver ink.

Features:
• Available in a variety of different sizes and thicknesses
• DT film element produces more than 10 millivolts per micro-strain

FDT_Series

Applications: Contact microphone, Dynamic strain gages, Speakers, Switches

Datasheet: FDT_Series

Description: The “F” in FDT Series stands for ‘Flexible Leads’. These are rectangle elements of piezo film with silver ink screen printed electrodes. Rather than making the lead attachment near the sensor, the piezo polymer tail extends from the active sensor area as flex circuit material with offset traces. This gives a very flat, flexible lead, with a connector at the end. The FDT elements are available in a variety of different sizes and thicknesses. They are available without a laminate (FDT), with a laminated (0.005” mylar) on one side (FLDT) or with tape release layer adhesive (FDT with adh) in the sensor area. The connector pins on the FDT sensors can be directly soldered to a PCB with a reasonable level of care. This component cannot withstand high temperatures (> 80°C), and therefore coldering of the pins to a PCB must be done quickly. A heatsink clamped to the interface area between the film and the crimps will take the heat away from the film. Pre-tin the pins and then quickly solder them to the board. Do not allow the soldering iron to touch the film, and do not use a dwell time of over 5 seconds on the pins. Low temperature solder can also be used.

Features:
• Very flat, flexible lead
• Available in a variety of different sizes and thicknesses
• Available without a laminate (FDT)
• Available with a laminated (0.005” mylar) on one side (FLDT)
• Available with tape release layer adhesive (FDT with adh) in the sensor area
• Connector pins on the FDT sensors can be directly soldered to a PCB with a reasonable level of care

LDT_Series

Applications: Beam-type vibration sensors for vehicle alarms, Solid state switches for counters, Momentary closure type switches

Datasheet: LDT_Series

Description: The ‘L’ in LDT Series stands for ‘laminated’ sensor. Typically, a 0.005” (125μm) polyester layer is laminated to a 28 μm or 52μm piezo film element. When used in a ‘bending’ mode, laminated film elements develop much higher voltage output when flexed than a non-laminated DT elements series. The neutral axis is in the laminate instead of in the film so the film is strained more when flexed. The capacitance is proportional to the area and inversely proportional to the thickness of the element. Piezo film sensors LDT elements are available in a variety of lead attachment options. For significantly increased sensitivity, the LDTM-028K (M-Mass) combines an LDT0-028K form factor with the addition of a 0.72 gram round mass. The LDT1, 2 and 4 have 12” of 26 gauge twisted pair wire. The LDT0-028K and LDTM-028K with solder tabs can be soldered directly to a PCB with a reasonable level of care. Piezo film cannot withstand high temperatures (>80°C), and therefore soldering of the pins to a PCB must be done quickly. A heatsink clamped to the interface area between the film and the crimps will take the heat away from the film. Pre-tin the PCB and then quickly solder the sensor to the board. Do not allow the soldering iron to touch the film, and do not use a dwell time of over 5 seconds on the pins. Low temperature solders can also be used. For tightly tolerance sensitivity requirements, please consult Measurement Specialties for techniques used to control variations of boundary conditions in production.

Features:
• The ‘L’ in LDT stands for ‘laminated’ sensor
• When used in a ‘bending’ mode, laminated film elements develop much higher voltage output than a non-laminated DT elements series
• Available in a variety of lead attachment options
• LDT0-028K and LDTM-028K with solder tabs can be soldered directly to a PCB with a reasonable level of care

LDT1_028K

Applications: Sensing direct contact force, Recording time of an event, Counting number of impact events, Measuring impact-related events, Sensing vibration using cantilevered beam, Wakeup switch, Motion detection

Datasheet: LDT1_028K

Description: The LDT1-028K is a multi-purpose, piezoelectric sensor for detecting physical phenomena such as vibration or impact. The piezo film element is laminate to a sheet of polyester (Mylar), and produces a useable electrical signal output when forces are applied to the sensing area. The dual wire lead attached to the sensor allows a circuit or monitoring device to process the signal.

Features:

• Piezoelectric polymer
• Multi-purpose
• Vibration sensing
• Impact sensing
• Laminated
• Dual wire lead attached
• Minimum impedance: 1 MΩ
• Preferred impedance: 10 MΩ and higher
• Output voltage: 10mV-100V depending on force and circuit impedance
• Storage temperature: -40°C to +70°C [-40°F to 160°F]
• Operating temperature: 0°C to +70°C [32°F to 160°F]

MiniSense_100

Applications: Detect either continuous or impulsive vibration or impacts

Industries: Medical, Engine and Vehicle, General Industry, Consumer Goods

Datasheet: MiniSense_100

Description: The MiniSense 100 is a low cost cantilever-type vibration sensor loaded by a mass to offer high sensitivity at low frequencies. Pins are designed for easy installation and are solderable. Horizontal and vertical mounting options are offered. The active sensor area is shielded for improved RFI/EMI rejection. Rugged, flexible PVDF sensing element withstands high shock overload. Sensor has excellent linearity and dynamic range, and may be used for detecting either continuous vibration or impacts. The mass may be modified to obtain alternative frequency response and sensitivity selection (consult factory). The MiniSense 100 acts as a cantilever-beam accelerometer. When the beam is mounted horizontally, acceleration in the vertical plane creates bending in the beam, due to the inertia of the mass at the tip of the beam. Strain in the beam creates a piezoelectric response, which may be detected as a charge or voltage output across the electrodes of the sensor. The sensor may be used to detect either continuous or impulsive vibration or impacts. For excitation frequencies below the resonant frequency of the sensor, the device produces a linear output governed by the "baseline" sensitivity. The sensitivity at resonance is significantly higher. Impacts containing high frequency components will excite the resonance fre-quency, as shown in the plot above (response of MiniSense 100 to a single half-sine impulse at 100 Hz, of amplitude 0.9 g). The ability of the sensor to detect low frequency motion is strongly influenced by the external electrical circuit.

Features:
• Low cost
• Cantilever-type vibration sensor
• High sensitivity at low frequencies
• Active sensor area is shielded for improved RFI/EMI rejection
• Excellent linearity and dynamic range
• Rugged, flexible PVDF sensing element withstands high shock overload

MiniSense 100 Analog PCB

Applications: Wakeup sensor, Drop detection sensor, Flow sensor, Activity sensor, Alarm trigger

Industries: General Industry

Datasheet: MiniSense 100 Analog PCB

Description: The LDTC MiniSense 100 Analog PCB provides a simple way to evaluate the LDTC MiniSense 100. The unit consists of LDTC MiniSense 100, a low-power operation amplifier, comparator, and DC/DC converter, and passive components used in signal conditioning. The sensor and circuit are assembled on a double-sided PCB with test points, ON/OFF switch, and 0.100” plated through holes for easy user interface. The PCB has adjustable gain and demonstrates the basic capabilities of LDTC MiniSense 100 vibration sensor.

Features:

• Evaluation Circuit for Vibration Sensor
• Low Power – Battery Powered
• LED for Trigger
• High Sensitivity
• Analog and Digital Signal Access Points
• Signal Conditioned Vibration Sensor
• High Pass Filter @ 1.3Hz
• Low Pass Filter @ 177Hz
• On Board 3.3 Battery or User Power Supply
• Both Analog and Digital Output

MiniSense 100NM (no mass)

Applications: Low cost vibration sensing, Car alarms, Body movement, Medical applications, Security systems

Datasheet: Minisense_100NM

Description: The MiniSense 100NM is a low-cost cantilever-type vibration sensor offering moderate sensitivity over a useful frequency band up to 200 Hz. Pins are designed for easy installation and are solderable. Horizontal and vertical mounting options are offered. The active sensor area is shielded for improved RFI/EMI rejection. Rugged, flexible PVDF sensing element withstands high shock overload. Sensor has excellent linearity and dynamic range, and may be used for detecting either continuous vibration or impacts.

Features:

• Low cost
• Cantilever-type vibration sensor
• High voltage sensitivity (65 mV/g)
• Higher resonant frequency
• Shielded
• Horizontal or vertical mounting
• Solderable pins, PCB mounting
• 1% Linearity
• Up to 200 Hz (12,000 rpm) operation below resonance
• Rugged; withstands high shock

SDT_Series

Applications: Contact microphone, Dynamic strain gage

Datasheet: SDT_Series

Description: The ‘S’ in SDT Series stands for ‘Shielded Sensor’. SDT1 piezo film sensors consist of a rectangular element of piezo film together with a molded plastic housing and 18” of coaxial cable. The film element, screen printed with silver ink, is folded over on itself, given a self-shielding of the transducer area. This is important in applications in high EMI environments. The SDT1 can be adhered to other surfaces using double sided adhesives, epoxy or cyanoacrylate (super-glue). Care should be taken if the sensor is to be removed, as the double-side adhesive can peel the metallization from the film. When adhered to a surface in this manner, the SDT1 is an excellent contact microphone or dynamic strain gage. The output from the SDT1 can input directly to an oscilloscope or a signal analyzer.

Features:
• Self-shielding of the transducer area
• Output from the SDT1 can input directly to an oscilloscope
• Output from the SDT1 can input directly to a signal analyzer