JPH08105838A - Adjusting device for quantity of light of discrimination sensor for unhulled/unpolished rice - Google Patents

Abstract

PURPOSE: To improve response and discrimination accuracy by wave-shaping voltage values of distributed grains on a discharging side of a rocking sorting board during a stable sorting state which are detected by a discrimination sensor for unhulled/unpolished rice for adjusting quantity of light. CONSTITUTION: Voltage generated by a discrimination sensor for unhulled/ unpolished rice 2 is read via a peak-hold circuit 4 and an integration circuit 5 to a 1-chip microcomputer 6 with an incorporated CPU from an analog input circuit AN. A peak of the voltage generated by the sensor 2 is detected by a peak detection circuit 7 to be read from an interruption input port IN to the microcomputer 6 and also synchronously input from the circuit 7 to the circuit 4. A 8-bit signal for adjusting quantity of light is output via an output port PO of the microcomputer 6, converted into voltage for adjusting quantity of light by a D/A-converter 8 and sent to the sensor 2. The detected voltage V1 sent to the circuit 7 is shaped into peak detection waves, while the voltage V1 sent to the circuit 4 is shaped into peak-hold waveforms V3 to be sent to the integration circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light quantity adjusting device for a rice / brown rice discrimination sensor.

[0002]

2. Description of the Related Art As a conventional technique, there is JP-A-3-2545.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The invention of Japanese Patent Application Laid-Open No. 3-2545 is a depletion rate sensor consisting of a light emitting element and a light receiving element, and has a predetermined number of grains of slid rice that has been hulled by a hulling roll. Voltage value is detected, a distribution chart is created, and the light amount is adjusted so that the maximum number distribution part of the distribution chart falls within a predetermined range.
This is to determine the threshold value for determining the brown rice, and it takes time to determine the threshold value, resulting in poor responsiveness.

Therefore, the present invention solves such a problem, speeds up the determination of the threshold value of paddy / brown rice, improves the responsiveness, and improves the responsiveness of the grain to the grain that is being hulled and sorted. It is intended to make them match and to be accurate.

[0005]

The present invention has taken the following technical means in order to solve the problems of the prior art. That is, according to the present invention, the paddy / brown rice discrimination sensor 2 capable of reciprocating between the rocking side 1c and the rocking side 1d on the discharge side 1b of the rocking sorting plate 1 and the discharging of the rocking sorting plate 1 in the proper sorting state. Waveform shaping means for shaping the detected voltage detected by the hull / brown rice discrimination sensor 2 for distributed grain on the side 1b, and waveform shaping means for shaping the peak-hold waveform into a waveform obtained by integral smoothing. And a light quantity adjusting means for adjusting the integral-smoothed waveform with a light quantity adjusting voltage to obtain a reference voltage value within a predetermined range.

[0006]

[Function] The mixed rice of paddy and brown rice is supplied to the rocking sorting plate 1, and while flowing from the supply side 1a to the discharge side 1b, the rocking side 1c
When reciprocating from the rocking side 1d to the rocking side 1d, brown rice is unevenly distributed on the rocking side 1c of the rocking sorting plate 1, and unhulled rice is unevenly distributed on the rocking side 1d. Are distributed while being distributed unevenly. From the upside 1c to the downside 1d on the discharge side 1b of the swing selection plate 1 in such a stable selection state.
The paddy / brown rice discrimination sensor 2 moves between the two, and the voltage value of the brown rice portion is detected. Then, the detected voltage value is shaped into a peak-hold waveform by the waveform shaping means, and the peak-hold waveform is obtained.
The rounded waveform is subjected to integral smoothing and shaped into an integral smoothed waveform. Next, the integrated smoothing waveform is adjusted by the light amount adjustment voltage and adjusted within a predetermined voltage value range, and the light amount of the paddy / brown rice discrimination sensor 2 is adjusted.

[0007]

Embodiments of the present invention shown in the drawings will be described below. First, the embodiment shown in FIGS. 1 to 3 will be described. The present invention relates to, for example, a light amount adjusting device for a paddy / brown rice discrimination sensor that optically detects a sorting state of a swing sorting device.

FIG. 1 (1) shows a known swing selecting device. Inclining the supply side 1a on one side in the vertical direction of the rocking sorting plate 1 to a higher position and the discharge side 1b on the other side to a lower position,
One side in the horizontal direction is the upper swinging side 1c, the other side is the lower swinging side 1d, and the mixed rice is fed and sorted from the supply side 1a in the vertical direction and from the swinging side 1c. It is a composition. While the mixed rice supplied to the swing selection plate 1 flows down from the vertical supply side 1a to the discharge side 1b, the mixed rice is reciprocally shaken up and down in the horizontal direction to be sorted, and small brown rice with a large specific gravity is The large-sized and light-weighted paddy is unevenly distributed on the rocking side 1c side, and is distributed on the rocking side 1d side, and unsorted mixed rice is sorted in the middle portion of these unbalanced rice. And
A brown rice partition plate (not shown) and a paddy partition plate (not shown) are provided so as to be movable from the rocking side 1c to the rocking side 1d so as to face the discharge side 1b of the rocking sorting plate 1.

A sample port 3 is provided facing the discharge side 1b of the swing selection plate 1 so as to be able to reciprocate between the most oscillating upper side 1c position and the most oscillating lower side 1d position. The sample port 3 has paddy / brown rice. This is a configuration in which the discrimination sensor 2 is provided to detect the inflowing grain. Note that the grain distributed on the plate surface of the swing selection plate 1 may be directly detected by the paddy / brown rice discrimination sensor 2. This sample mouth 3 and paddy / brown rice discrimination sensor 2
Are reciprocally moved by a movement adjusting means (not shown) composed of a screw rod and a sensor movement motor (not shown).

Next, FIG. 1B will be described. Paddy
The brown rice discrimination sensor 2 is composed of a light emitting element and a light receiving element, and has a configuration in which the amount of reflected light or the amount of transmitted light of the grain is converted into a voltage by the light receiving element and the distinction between paddy and brown rice is detected. The generated voltage of the paddy / brown rice discrimination sensor 2 is read from the analog input circuit AN to the one-chip microcomputer 6 with a built-in CPU via the peak-hold circuit 4 and the integrating circuit 5. The peak voltage of the paddy / brown rice discrimination sensor 2 is detected by the peak detection circuit 7 when the peak voltage is detected, and is read from the interrupt input port INT to the one-chip microcomputer 6 and at the same time, the peak is detected. It is synchronously input from the peak detection circuit 7 to the peak hold circuit 4. Also, the output port P of the 1-chip microcomputer 6
An 8-bit light intensity control signal is output via O, and D / A
The conversion circuit 8 converts the light amount adjustment voltage and sends it to the paddy / brown rice discrimination sensor 2.

When the grain is detected by the paddy / brown rice discrimination sensor 2, a detection voltage V1 as shown in the first part of FIG. 1 (3) is generated, and the subsequent peak-hold circuit 4 and −
Is sent to the black detection circuit 7. The detection voltage V1 sent to one of the peak detection circuits 7 is shaped into a peak detection waveform as shown in the second part of FIG.
Input from NT to 1-chip microcomputer 6 and
It is synchronously input to the hold circuit 4.

On the other hand, the detection voltage V1 sent to the peak-hold circuit 4 is shaped into a peak-hold waveform V3 as shown in the third part of FIG. Sent to. In the integrating circuit 5, as shown in the fourth part of FIG. 1 (3), it is shaped into an integrated smoothed waveform V4 and is input from the analog input port AN to the one-chip microcomputer 6. Next, the light amount adjustment control will be described based on the flow chart of FIG.

When the swinging sorting plate 1 is in a stable sorting state, that is, in a stable sorting state in which grains are distributed over the entire width from the upside 1c to the downside 1d, and brown rice, mixed rice, and paddy are unevenly distributed, the operation is performed. When the switch turns on the operation switch (not shown) (a grain sensor (not shown) arranged on the rocking sorting plate 1 detects a stable sorting state, and when the stable sorting state is reached, the starter automatically starts.
It may be configured so that ), Light intensity adjustment control starts.

Then, the one-chip microcomputer 6 sets and sends the initial reference light amount adjustment voltage V2 (for example, 5V) (ST10). Next, from the 1-chip microcomputer 6
A movement command signal is output from the most swaying upper side 1c of the brown rice discrimination sensor 2 to the most swaying lower side 1d, and the paddy / brown rice discrimination sensor 2 starts moving. Then, the detection voltage V1 from the paddy / brown rice discrimination sensor 2 is, as shown at the first in FIG. 2 (1), the brown rice having a non-uniform distribution in the upswing 1c has a small voltage, and the mixed rice in the middle portion. The ones of the paddy distributed on the rocking side 1d of the rocking / sorting plate become the high voltage and are detected respectively while the voltage gradually increases from the small voltage to the high voltage (ST2).
0).

Next, the detection voltage V1 is input to the peak detection circuit 7, shaped into a peak detection waveform V2 as shown in FIG. 1 (2), and read into the one-chip microcomputer 6. , And are synchronously sent to the peak-hold circuit 4. Further, the detected voltage V1 is also sent to the peak-hold circuit 4, and as shown at the third position in FIG.
It is shaped into a rectangular waveform. Next, it is sent to the integration circuit 5, shaped into an integral smoothing waveform V4, and read by the 1-chip microcomputer 6, as shown in the fourth part of FIG.
Then, the brown rice detection voltage value is determined and stored from several times of the voltage value detected on the uppermost sway 1c of the detection voltages and the equivalent voltage value subsequently detected (ST20).

Next, the brown rice reference voltage V0 (which can be adjusted by setting adjusting means not shown) stored in the storage unit of the one-chip microcomputer 6 and the brown rice voltage value of the detected voltage value V4 read from the integrating circuit 5 Are compared (ST3
0). When the brown rice detection voltage value V4 is lower than the brown rice reference voltage value V0, the one-chip microcomputer 6 issues a command signal to increase the light amount adjustment voltage by one step, and the increase light amount is adjusted (ST40). When V4 is higher than the brown rice reference voltage V0, a command signal for lowering the light amount adjustment voltage by one step is issued (ST50), and the grain detection voltage value is read again (ST30).

Then, the brown rice reference voltage V0 is compared with the brown rice voltage value of the detection voltage value V4 read from the integrating circuit 5 (ST30), and the brown rice detection voltage value V4 is within the range of the brown rice reference voltage V0. Then, it is judged whether or not the detected voltage value V2 of the grain is interrupt-input to the interrupt input port INT (ST60), and when the interrupt input is not made, an abnormal display is displayed on the display unit (not shown). Made,
When the interrupt input is made, the light amount adjustment control ends.

As described above, the detection voltage of brown rice distributed on the upper side 1c of the rocking sorting plate 1 in the stable sorting state is compared with the brown rice reference voltage, and the paddy / brown rice discrimination sensor 2 is compared.
Since the light amount is adjusted, the detection voltage can be quickly determined, and the light amount can be adjusted quickly, and the light amount can be adjusted to the actual grain.

Next, the embodiment shown in FIGS. 4 and 5 will be described. This control is performed after the above-described light amount adjustment control is completed, and determines the control reference value of the partition plate sensor that controls the brown rice partition plate of the swing selection plate 1. FIG.
Shows a known swing sorting device, the swing sorting plate 1 is configured in the same manner as the above-mentioned embodiment, and the paddy / brown rice discrimination sensor 2 is provided on the discharge side 1b of the swing sorting plate 1. , By the sensor moving means 9 consisting of a screw rod, from the rocking side 1c to the rocking side 1c
It is supported so as to be reciprocally movable toward d, and is reciprocally moved by forward or reverse rotation of the sensor adjustment motor 10. A brown rice partition plate 11 and a paddy partition plate 12 for partitioning the selected grains are arranged facing the discharge side 1d of the swinging and sorting plate 1, and the brown rice partition plate 11 is a partition plate moving means 1 made of a screw rod.
It is reciprocally supported by 3 and is reciprocally moved by rotating the partition plate adjusting motor 14 in the forward or reverse direction. A brown rice partition plate sensor 15 is attached to the brown rice partition plate 11 so that the brown rice partition plate sensor 15 detects the grain of the brown rice partition plate 11 which is slightly on the rocking side 1d from the brown rice partition position.

Next, FIG. 4B will be described. The detection information of the paddy / brown rice discrimination sensor 2 and the brown rice partition plate sensor 15 is input to a control unit 18 with a built-in CPU via an input interface (not shown). To output interface (not shown)
A control command signal is output to the sensor adjustment motor 10 and the partition plate adjustment motor 14 via the.

Next, the control contents will be described based on the flow chart shown in FIG. When the light amount adjustment of the paddy / brown rice discrimination sensor 2 of the embodiment shown in FIGS. 1 to 3 is finished, the control shifts to the control reference voltage calculation control of the brown rice partition plate sensor 15 of the rocking sorting plate 1 (ST110). Then, a movement command signal to the swaying side 1d is issued to the brown rice partition plate 11 located on the uppermost rocking upper side 1c, and the brown rice partition plate sensor 15 moving together with the brown rice partitioning plate 11 detects the detection voltage every predetermined time. V is read. Then, the detection voltage V and the paddy detection voltage value VM in the above embodiment are compared, and the detection voltage V is the paddy detection voltage value V.
When it is larger than M, a movement command signal to the swinging side 1c is issued to the partition plate adjusting motor 14, and when the detection voltage V is smaller than the paddy detection voltage value VM of the above embodiment. Is
A movement command signal to the swinging side 1d is output to the partition plate adjusting motor 14, and the brown rice partition plate sensor 15 is moved to the swinging side 1d. During such a movement, when the detection voltage value V detects the paddy detection voltage value VM and the brown rice detection voltage value VK of the above-mentioned embodiment, it is read into the one-chip microcomputer 6 (ST150).

Next, the calculation formula VS = (VM + VK) × 1
/ 2 × α, the paddy detection voltage value VM, brown rice detection voltage value V
K, correction constant α (for example, it is determined by the selection characteristics based on the variety, the water content, the green rice mixing rate, etc.) are calculated,
The control reference voltage value VS of the brown rice partition plate sensor 15 for controlling the brown rice partition plate 11 is determined. In this way, the control reference voltage value VS of the brown rice partition plate sensor 15 is determined (ST1
60), the control reference value calculation control of the brown rice partition plate sensor 15 ends (ST170), and thereafter, a control command signal for positioning the brown rice partition plate sensor 15 at the position for detecting the control reference value VS is issued, and the brown rice Adjustment control of the partition plate 11 is performed.

Next, the embodiment shown in FIGS. 6 and 7 will be described. This embodiment is performed after the reference voltage value calculation control of the brown rice partition plate sensor 15 of the embodiment shown in FIGS. 4 and 5, and the operator is operated during the automatic control of the brown rice partition plate 11. The present invention relates to changing the control reference value of the brown rice partition plate sensor 15 when the brown rice partition plate 11 is manually adjusted.

Next, FIG. 6 will be described. The paddy / brown rice discrimination sensor 2 is configured to be capable of reciprocating from the rocking upper side 1c to the rocking lower side 1d of the rocking sorting plate 1 by the sensor moving means 9 and the sensor adjusting motor 10, and the brown rice partition plate 11 is The partition plate adjusting means 13 and the partition plate adjusting motor 14 are also reciprocally movable. This brown rice partition plate 11 is provided with a brown rice partition plate sensor 15 that moves integrally, and the grain on the plate surface of the discharge side 1b of the swing selection plate 1 or the grain in the middle of falling from the discharge side 1b. Is a configuration that can detect Further, the brown rice taken out from the discharge side 1b of the rocking / sorting plate 1 is sent to a brown rice lifting machine (not shown) through a brown rice taking-out passage (not shown) and taken out of the machine. A brown rice switching valve (not shown) is provided in this brown rice extraction passage. When the brown rice switching valve is switched to the outside extraction side, the brown rice flows to the brown rice lifting machine and is taken out of the machine, and is also circulated inside the machine. When it is switched to the side, it is circulated in the machine through a mixed rice fried machine (not shown) and supplied again to the swing selection plate 1.

The above-mentioned paddy / brown rice discrimination sensor 2, brown rice partition plate sensor 15, and brown rice partition plate 11 are manually adjusted to the rocking upper side 1c, and the partition plate rocking upper side adjustment switch 16 and the brown rice partition plate 11 are manually adjusted to the rocking lower side 1d. Partition plate swing down adjustment switch 1
7 is a C via an input interface (not shown).
The configuration is input to the control unit 18 with a built-in PU.
A switching motor 19 for switching the partition plate adjusting motor 14 and the brown rice switching valve (not shown) from the control section 18 to the outboard side or the in-machine circulation side via an output interface.
In addition, the control command signal is output.

Next, the control reference value adjustment control of the brown rice partition plate sensor 15 will be described with reference to the flow chart of FIG. Brown rice partition plate sensor 15 of the embodiment shown in FIG. 4 and FIG.
When the reference voltage value calculation control of (2) is completed (ST210), the brown rice partition plate sensor 15 starts adjusting control of the brown rice partition plate 11. Then, the detected voltage value V is read from the brown rice partition plate sensor 15 and compared with the control reference value VS, and when the detected voltage value V is smaller than the control reference value VS, the partition plate adjustment motor 14 is swung. A movement command signal to the upper side 1c is issued, the partition plate adjusting motor 14 rotates forward, and the brown rice partition plate 1
1 and the brown rice partition plate sensor 15 are moved to the upper side 1c by one step (ST230), and when the detected voltage value V is larger than the control reference value VS, the partition plate adjusting motor 14 is moved to the lower side 1d. Movement command signal is output, the partition plate adjustment mode
14 reversely, and the brown rice partition plate 11 and the brown rice partition plate sensor 15 are moved and adjusted one step to the swaying side 1d (S
T240).

While being adjusted in this way, the detected voltage value V
Is within the range of the control reference value VS, the brown rice partition plate 11 and the brown rice partition plate sensor 15 are at proper partition positions, so that the position is maintained without the movement command signal being output, and then the switching motor 19 is operated. A control command signal is output to, and the brown rice switching valve (not shown) is switched from the in-flight circulation side to the outboard discharge side, and the brown rice partitioned by the brown rice partition plate 11 passes through the brown rice extraction passage and the brown rice lifting machine. , Taken out of the machine (ST2
50).

Next, when the brown rice partition plate 11 is manually adjusted by the operator, the control shifts to the control reference value of the brown rice partition plate sensor 15. When the partition plate swing-up adjustment switch 16 is turned on (ST260), the partition plate adjustment mode is selected.
The brown rice partition plate 11 and the brown rice partition plate sensor 15
It moves to the rocking side 1c and is adjusted to the side where the sorting efficiency is slightly lowered and the sorting precision is increased (ST270). Then, the detected voltage value VS1 is read from the brown rice partition plate sensor 15 that has moved to the upper side 1c together with the brown rice partition plate 11, and the control reference value is changed from the reference value VS to the correction reference value VS1.

Further, the partition plate swing-down adjustment switch 17 is set to O.
When it is N (ST260), the partition plate adjusting motor 14 adjusts the brown rice partition plate 11 and the brown rice partition plate sensor 15 to the swaying side 1d (ST290), and the sorting efficiency is increased even if the sorting accuracy is lowered. Adjusted. Then, the detected voltage value VS2 is read from the brown rice partition plate sensor 15 that has moved to the swaying side 1d together with the brown rice partition plate 11, and the control reference value is the reference value V.
The correction reference value VS2 is changed from S. Then, after the operator manually adjusts the brown rice partition plate 11, the brown rice partition plate 11 is adjusted with reference to the corrected correction reference value V1 or V2, and selection according to the operator's preference can be performed.

Next, the embodiment shown in FIGS. 8 and 9 will be described. Swing selection plate 1, paddy / brown rice discrimination sensor 2, sensor moving means 9, sensor adjustment motor 10, brown rice partition plate 1
1, the paddy partition plate 12, the partition plate adjusting means 13, the partition plate adjusting motor 14, and the control unit 18 are configured in the same manner as in the above-described embodiment. Reference numeral 15 denotes a brown rice partition plate sensor composed of a transmissive photo sensor, which is attached to the brown rice partition plate 11.

In FIG. 9 (1), the horizontal axis indicates the brown rice partition plate 1
1 shows the moving position, PK shows the position where brown rice is distributed in the stable state of selection, PM shows the position where rice is distributed in the same state, and the vertical axis shows the detection of the brown rice partition plate sensor 15. Voltage value, VK indicates the detection voltage value of the brown rice partition plate sensor 15 at the PK position of the brown rice partition plate 11, and VM indicates the detection voltage value of the brown rice partition plate sensor 15 at the PM position of the brown rice partition plate 11. .

Next, the calculation control of the control reference value of the brown rice partition plate sensor 15 will be described with reference to the flow chart of FIG. 9 (2). When the mixed rice is supplied to the rocking sorting plate 1 and the sorting state is stabilized, calculation control of the control reference value of the brown rice partition plate sensor 15 is started. Then, a movement command signal to the brown rice partition plate 11 and the brown rice partition plate sensor 15 is sent to the brown rice distribution basin on the rocking side 1c and the rice is moved. At every predetermined time during the movement, the detection voltage value V of the brown rice partition plate sensor 15 is detected and read by the control unit 18, the detection voltage value V is compared with the reference voltage value VK (ST310), and the detection voltage is detected. When the value V is smaller than the brown rice reference voltage value VK, a movement command signal of the brown rice partition plate sensor 15 to the upside 1c is issued, and the brown rice partition plate sensor 15 is moved up to the upside 1c (ST320). When V is larger than the brown rice reference voltage value VK, a movement command signal for the brown rice partition plate sensor 15 to the swaying side 1d is issued, and it moves to one step swaying side 1d (ST.
330).

When the detected voltage value V becomes equal to the brown rice reference voltage value VK and the brown rice partition plate 11 partitions the brown rice, the light amount adjustment of the paddy / brown rice discrimination sensor 2 is started. Then, sample grains are supplied from the brown rice distributed in the brown rice distribution basin on the upper side 1c of the swing selection plate 1 to the paddy / brown rice discrimination sensor 2, and the detection voltage is input to the control unit 18. Next, the detected voltage is compared with a predetermined reference threshold value, and when the detected voltage value is large, the light amount is adjusted to the decreasing side in sequence, and when the detected voltage value is small, the light amount is adjusted to the gradually increasing side, When the detected voltage value falls within the range of the reference threshold value, the light amount adjustment ends (ST340).

As described above, since the amount of light of the paddy / brown rice discrimination sensor 2 is determined based on the brown rice used for the paddy sorting operation, the accuracy of calculating the paddy mixing rate is improved.

[0035]

As described above, according to the present invention, the voltage value detected by the paddy / brown rice discrimination sensor 2 of the distributed grain on the discharge side 1b of the rocking sorting plate 1 in the sorting stable state is peaked.
Since the light intensity of the shaped waveform and integral smoothing waveform is adjusted, the determination threshold of the paddy / brown rice can be determined quickly and the responsiveness can be improved. Is detected to determine the threshold value, the discrimination accuracy is improved.

[Brief description of drawings]

FIG. 1 is a plan view, a block diagram, and a diagram showing waveforms of detected voltage values.

FIG. 2 is a diagram and a graph showing waveforms of detected voltage values.

[Fig. 3] Flow chart

FIG. 4 is a perspective view

[Fig. 5] Flow chart

FIG. 6 is a perspective view and a block diagram.

[Fig. 7] Flow chart

FIG. 8 is a perspective view and a block diagram.

FIG. 9: Graph and flow chart

[Explanation of symbols]

 1 Swing Selection Plate 2 Paddy / Brown Rice Discrimination Sensor 3 Sample Port 4 Peak Hold Circuit 5 Integrating Circuit 6 1 Chip Microcomputer 7 Peak Detection Circuit 8 D / A Conversion Circuit 9 Sensor Moving Means 10 Sensor Adjustment Motor 11 brown rice partition plate 12 paddy partition plate 13 partition plate adjusting means 14 partition plate adjusting motor 15 brown rice partition plate sensor 16 partition plate swinging up adjustment switch 17 partition plate swinging down adjustment switch 18 control section 19 switching motor

Claims (1)

[Claims] 1. A paddy / brown rice discrimination sensor 2 capable of reciprocating between a swing-up side 1c and a swing-down side 1d on a discharge side 1b of a swing sorting plate 1, and a discharge side of the swing sorting plate 1 in a proper sorting state. Waveform shaping means for peak-hold shaping the detection voltage detected by the paddy / brown rice discrimination sensor 2 of the distributed grain in 1b;
It comprises waveform shaping means for shaping the peak-hold waveform into a waveform obtained by integral smoothing, and light quantity adjusting means for adjusting the integral smoothed waveform with a light quantity adjusting voltage to obtain a reference voltage value within a predetermined range. Light intensity adjustment device for rice / brown rice discrimination sensor.