Chip senses gesture through electric fields
The PS25401A is an ultra high impedance non-contact solid state electric potential sensor. It can be used to detect field disturbance due to the movement of a near-by object. This functionality can be employed in a range of applications including security motion sensors and non-contact electric switches for lighting, door opening, toys etc
The device uses active feedback techniques to both lower the effective input capacitance of the sensing element (Cin) and boost the input resistance (Rin). These techniques are used to realize a sensor with a frequency response suitable for remote sensing applications.
Also known as PS25401A EPIC Sensor.
- Ultra high effective input resistance, typically 20GΩ.
- Effective input capacitance as low as 15pF.
- Upper 3dB point typically 10kHz.
- Operates with bipolar power supply from ±2.4V to ±4.0V.
- Sensors supplied in a custom package with exposed pins for surface mount assembly
Plessey has released an electrostatic field sensing chip for security, switching and gaming applications.
It is the second member of the firm’s EPIC (electric potential IC) range, the first of which was a non-contact EEG (heart waveform) monitor.
“We have optimised the base layout of the EPIC sensor chip such that discrete movements of the human body can be detected with a range of up to several metres,” said Plessey CTO Dr Keith Strickland. “For example, the sensor can be configured to detect the proximity of a hand or to detect specific hand motions depending on the chip variant and the appropriate selection of circuit components external to the sensor.”
Called PS25401, the new chip can detect movement through walls, said Plessey, and can drive a relay “to act as a simple non-touch electric switch. It can also be used to replace, or as an adjunct to, a passive infra-red (PIR) sensor.”
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