Oil contamination particle detection board (2)-sensor signal board

Introduction: Oil pollution particle counting circuit based on the principle of photoresist method

1. Product introduction:

This module is the sensor signal board of the oil pollution particle detection board. It can process laser emission and photoelectric reception signals, and perform I/U on the signals. Convert, filter, amplify, and output to power supply and counting board. The sensor signal board cannot be used alone and needs to be used in conjunction with a power supply and counting board to achieve the effect of counting pollution particles.

2. Application scenarios:

It can be applied to equipment use and development projects such as portable oil particle detectors.

3. Product overview:

The sensor signal board is one of the important components of the oil pollution particle detector. It mainly converts the oil particle signal into a voltage signal. In the detection board, the laser diode is driven by a driver chip to achieve constant power control; the I/U conversion converts the current signal received by the photoelectric receiving tube into a voltage signal; the filtering part filters out the high-frequency signals in the circuit and retains all The signal range is required; the amplification part amplifies the weak voltage signal, which can better extract the voltage range of different particles and facilitate comparison.

4. Product parameters:

Working voltage: ±15V, 5V, 3.3V
Measurement particle range: including 4, 6, 14, 21, 38, 70 (μm)
No-load test power: about 1.5W
PCB size: 55mm*60mm double layer Board design single-sided layout

5. Instructions for use:

This module needs to be used with a power supply and counting board (see my personal homepage for details of the power supply and counting board).
After getting the module for the first time, connect the sensor signal board to the power supply and counting board. The interface is as follows As shown in the schematic diagram.
According to actual usage requirements, after testing, connect to the detector, modify the corresponding program and adjust the internal structure to fully adapt to the testing equipment.

6. Remarks:

This module is a pure hardware circuit. First, connect it according to the above schematic diagram; secondly, according to the actual project needs, formulate the appropriate sensor detection mechanical structure, main control chip and other models. Finally, the overall debugging is carried out to meet the design requirements.
This module is only a power supply and counting board, and needs to be matched with the sensor signal board to achieve the effect of counting pollution particles. For details about the power supply and counting board, please see my homepage (Oil contamination particle detection board (1) - Power supply and counting board).
It is estimated that the cost of all materials for the oil contamination particle detection boards (1) and (2) is about 500 yuan (excluding PCB).
This design has certain adaptability and can be used with various detectors on the market after further modification according to their design requirements.
According to different liquid particles, the actual test value is obtained, and calibrated with the offline test instrument to finally obtain the true value.
The attachment contains pin definition instructions for the sensor signal board.
Note that a certain component is not soldered: Silk screen number: L65P007 (laser diode) is not soldered. Reason: The laser diode has a spare interface. This time, the three pin header expansion interfaces above are used for external connection. Silk screen number: LED1 (photoelectric receiving tube) is not soldered. Reason: The photoelectric receiving tube has a spare interface. This time, the two pin header expansion interfaces on the top are used for external connection.
7. Test video

demonstration video is a joint test of the power supply, counting board and sensor signal board, simply simulating particle changes, and testing the output voltage changes by continuously blocking the light signal.