The EVAL-ADPD410x-ARDZ allows users to take advantage of the flexibility of the ADPD4100 and ADPD4101 as multimodal sensor front ends to a wide range of applications. One example of a specialized application is the CN0503, a reference design for optical water quality measurement. This demonstration shows how to perform fluorescence measurement using the EVAL-ADPD410x-ARDZ, similarly to the CN0503 Fluorescence Measurement Demo.
One method of measuring the amount of substance in a sample is by using fluorescent light. In this setup, a light is passed from a monochromatic source through the sample, and then the fluorescence in the substance is measured using a detector tuned to its wavelength. The intensity of the fluorescent light compared to the intensity of the incident light will be proportional to the amount of the fluorescent substance in the sample. An effective way of performing this is by using the setup shown below.
Light is emitted from an LED at 365 nm wavelength. It then passes through a beam-splitter, which directs some of the incident light to a reference photodiode detector for sampling. Quinine in the sample fluoresces due to the 365 nm light and emits ~450 nm light. Another photodiode detector, sensitive to blue light frequencies, is positioned at 90 degrees from the light path to measure the intensity. This placement decreases the effects of the light emitted from the source LED. Additionally, a monochromatic filter is placed in front of the detector to further isolate the measurement.
The following is a list of items needed to replicate this demo.
Configure the onboard jumper header and solder jumper connections, as shown below.
|Shorted Pin 2 and Pin 3
|Shorted Pin 1 and 2
Set the following EVAL-ADICUP3029 switches according to their configuration on the table below.
Pre-built hex files can be found here:
The latest source code can be found here:
The demo utilizes an optical path similar to the one used by CN0503, but only for a single channel. The single path base and cuvette holder are available as 3D-printable designs () and can also be ordered using Shapeways.
Connect the 365 nm LED Board, Transmit Photodiode Board, and Fluorescence Photodiode Board to the prototyping connectors of the EVAL-ADPD410x-ARDZ, as shown below.
This demo uses a PyADI-IIO example script. See Software Setup for the complete installation instructions from libiio to pyadi-iio.