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Low-Cost Surface-Mount Led Gas Sensor, Roderick Shepherd, William S. Yerazunis, King Tong Lau, Dermot Diamond
Low-Cost Surface-Mount Led Gas Sensor, Roderick Shepherd, William S. Yerazunis, King Tong Lau, Dermot Diamond
Australian Institute for Innovative Materials - Papers
A low-cost chemical sensor comprising surface-mount light-emitting diodes (LEDs) has been developed for colorimetric gas detection. The device consists of a pair of LEDs connected to a simple PIC microcontroller circuit and in the most basic form, requires the use of only two input-output (I/O) pins on the chip. The key features of this sensor are the use of a LED rather than a photodiode for light detection and an all-digital light detection protocol that leads to a reduction in cost and power consumption by avoiding the need for an analog-to-digital converter. The surface-mount diodes employed are more compact than …
Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond
Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond
Australian Institute for Innovative Materials - Papers
A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microsecond) it takes for the photocurrent generated on the detector LED to discharge its capacitance from logic 1 (+5 V) to logic 0 (+1.7 V). The entire instrument provides an inherently digital output of light intensity measurements for a few cents. A …