Measuring contact pressure
PPS patented capacitive tactile sensors capture pressure data by measuring capacitance, which is the ability to store an electrical charge. Over the past two decades, PPS sensor technology delivered valuable insights to many applications that needed to measure contact pressures for product design, process optimization and research and development. Integrating PPS capacitive tactile sensors, either in the final product or during the development process, empowers engineers and researchers to capture “the sense of touch” and create more innovative products.
Resistive tactile sensing is the primary competing technology. This technology utilizes the resistance of a conductive material, such as an elastomer, foam, or conductive ink, to detect pressures.
Applications that require high levels of accuracy and sensitivity are better served by the use of PPS’s capacitive sensors. PPS sensors offer greater stability than resistive sensors because their electrodes don’t have to make direct contact with each other. They are also easier to calibrate, better at providing repeatable readings, and less susceptible to wear and tear than resistive sensors, which suffer over time as the ink ages.
Capacitive Sensor Technology
Delivers twice the repeatability, 100x better minimum pressure detection, and 50% better pressure sensing resolution compared to typical resistive tactile sensing technologies.
Saves time and improves results by significantly reducing recalibration and repeated tests allowing developers to resolve problems and answer questions faster.
Has been used to map contact pressures in many real-world applications to provide stable and repeatable sensor output even for curved surface applications.
- Operates accurately and reliably at pressures up to 700 psi and temperatures up to 200C.
Capacitive Tactile Sensors
Resistive Tactile Sensors
PPS Capacitive Sensing for Single Point and Distributed
Capacitive Tactile Sensing: Technology Primer
The basic electrical property of capacitance – a measure of an object’s ability to store electrical charge – has been demonstrated in countless physics classes with the classic example of two electrodes with area A separated by an air gap d as shown. If the air gap decreases, the capacitance C goes up.
PPS Capacitive Tactile Sensors
PPS uses this property to build its tactile pads and arrays by separating the electrodes using a proprietary compressible dielectric matrix, which acts as a spring. Precision manufacturing techniques allow excellent repeatability and sensitivity, while advanced conductive materials allow for conformable, stretchable, industrial, and other hybrid sensor designs. The simplicity of the capacitive sensor design gives PPS a large degree of flexibility when creating custom sensor solutions.
PPS Array Sensors
To build tactile array sensors, PPS arranges the electrodes as orthogonal, overlapping strips. A distinct capacitor is formed at each point where the electrodes overlap. By selectively scanning a single row and column, the capacitance at that location, and thus the local pressure, is measured. PPS’s proprietary drive and conditioning electronics can scan through an array at high speed while optimizing settings to achieve the maximum sensor response from each sensing element.