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The authors are working toward the design of a device for the detection of oxygen, following a discrete and an integrated
instrumentation implementation. The discrete electronics are also used for preliminary analysis, to confirm the validity of
the conception of system, and its set-up would be used in the characterization of the integrated device, waiting for the
chip fabrication.
This paper presents the design of a small and portable potentiostat integrated with electrodes, which is cheap and
miniaturized, which can be applied for on-site measurements for the simultaneous detection of O2 and temperature in
water systems.
As a first approach a discrete PCB has been designed based on commercial discrete electronics and specific oxygen
sensors. Dissolved oxygen concentration (DO) is an important index of water quality and the ability to measure the
oxygen concentration and temperature at different positions and depths would be an important attribute to environmental
analysis. Especially, the objective is that the sensor and the electronics can be integrated in a single encapsulated device
able to be submerged in environmental water systems and be able to make multiple measurements.
For our proposed application a small and portable device is developed, where electronics and sensors are miniaturized
and placed in close proximity to each other.
This system would be based on the sensors and electronics, forming one module, and connected to a portable notebook to
save and analyze the measurements on-line.
The key electronics is defined by the potentiostat amplifier, used to fix the voltage between the Working (WE) and
Reference (RE) electrodes following an input voltage (Vin). Vin is a triangular signal, programmed by a LabView©
interface, which is also used to represent the CV transfers.
To obtain a smaller and compact solution the potentiostat amplifier has also been integrated defining a full custom ASIC
amplifier, which is in progress, looking for a point-of-care device. These circuits have been designed with a 0.13 μm
technology from ST Microelectronics through the CMP-TIMA service.
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