JPH074622Y2 - Object passage detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an object passage detecting device for detecting passage of an object using an optical sensor.

(B) Related Art There is known an object passage detecting device that detects passage of an object by transmitting or reflecting light using an optical sensor including a light emitter and a light receiver.

(C) Problems to be Solved by the Invention However, the object passage detection device using the conventional optical sensor is easily affected by the incident light from the outside, and in particular,
When the incident light fluctuates, there is a problem that it causes erroneous detection.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems and provide a highly reliable object passage detection device that does not cause erroneous detection even when fluctuating ambient light enters.

(D) Means for solving the problem For this reason, the present invention calculates the set value according to the detection value output from the light receiver after a certain time when the light emitter is turned off, and detects the detection value at that time. Then, the difference between the detected value output from the light receiver is obtained after a certain time has passed since the light emitter was turned on, and the difference is compared with the set value to detect passage through the object.

(E) Action A stable detection value can be obtained by taking out the output of the photodetector after a certain time has passed since the photoemitter was turned on and off.
By determining the set value each time based on the detected value, the set value becomes a value in which the ambient light at each time is taken into consideration, and correct detection can be performed without the influence of the ambient light.

(F) Embodiment An embodiment will be described below by taking the case where the present invention is applied to detection of passage of coins in a coin sorting device of a vending machine as an example.

FIG. 1 shows a coin passage in a coin sorting device of a vending machine, and a coin inspection sensor 3 is arranged in the coin passage 2 in order to discriminate whether the inserted coin 1 is true or false. The coin passage behind the inspection sensor 3 is divided into a forked coin passage 2a for passing a positive coin and a false coin passage 2b for passing a false coin.
A coin passage switching device is provided at the entrance of 2a. This coin passage switching device includes a switching plate 4 which moves in and out of the coin passage by a solenoid (not shown), and normally the solenoid is de-excited to cause the switching plate 4 to project inside the passage to close the entrance of the positive coin passage 2a. I'm out. Behind the switching plate 4, an optical passage sensor 5 for detecting passage of the coin 1 is provided.
Is provided.

The coin sorter having such a configuration is provided behind the front door of the vending machine and near the front opening of the vending machine body whose front opening is closed by the front door. However, the front door is provided with a signboard part equipped with an illumination lamp and a product sample display room. Therefore, there is a possibility that the light of the illumination lamp or a part of the ambient light in which the vending machine is installed may be inserted into the passage sensor 5 and the level of the light receiver may be changed to cause an erroneous detection.

In order to prevent this, in this embodiment, the coin passage detecting device is configured and operated as follows. That is, FIG. 2 is a block diagram showing the structure of the coin passage detecting device.
A microcomputer (hereinafter abbreviated as "microcomputer") 6,
A series circuit connected from its output end to the ground via the amplifier 7, resistor 8 and light emitting diode 9, and from the power supply to the ground via the phototransistor 11, and at the same time from the output end of the phototransistor 11 to the resistor A / D And a circuit connected to the input terminal of the microcomputer 6 via the converter 13. The inspection sensor 3 is also connected to the microcomputer 6.

With the above configuration, when the inserted coin 1 reaches the inspection sensor 3, the microcomputer 6 compares the data obtained from the inspection sensor 3 with the positive coin reference data stored in advance, and confirms the authenticity of the coin 1. to decide. As a result, the microcomputer 6
When it is determined that the coin is a positive coin, the solenoid of the coin passage switching device is excited to retract the switching plate 4 from the coin passage,
The coin 1 is passed through the normal coin passage 2a. On the other hand, when it is determined that the coin is a false coin, the switching plate 4 is projected into the coin passage while the solenoid is not excited, and the coin 1 is rolled into the false coin passage 2b to return.

When the microcomputer 6 determines that the coin 1 passing through the inspection sensor 3 is a true coin, as shown in (a) of FIGS. 3 and 4, the point A in FIG. 2 turns on for 1 msec and turns off for 2 msec for 3 msec. The rectangular wave signal having a cycle is continuously output for a time sufficient for the coin 1 to pass through the passage sensor 5. The light emitting diode 9 repeats light emission and extinction by this rectangular wave signal. Furthermore, the waveform at the point B is the third depending on the blinking state of this light.
It changes as shown in FIGS. 4 (b) and 4 (c).

Here, FIG. 3 shows that when there is no coin 1 in the passage sensor 5,
FIG. 4 shows the case, and FIG. 3 and FIG. 4 (b) show the case where the external light does not enter the passage sensor 5, and FIG.

The microcomputer 6 waits for the output state of the phototransistor 11 to stabilize after the rectangular wave signal output to the light emitting diode 9 is turned off or on, and then outputs the output of the phototransistor 11 after T ₁ or T ₂ to the sensor detection value V ₁ Alternatively, the presence or absence of the read coin 1 is determined as V ₂ . That is, as shown in FIG. 5, the microcomputer 6, the light emitting diode 9 reads the sensor detection value v ₁ during quenching (50), sets the coin presence detection reference value alpha to α = V _1/3 (51 ). Next, the difference between the sensor detection value V ₁ at the time of extinction and the sensor detection value V ₂ at the time of light emission is compared with the reference value α (52), and when V ₁ −V ₂ <α, it is determined that there is a coin (53). . When V ₁ −V ₂ α, it is determined that there is no coin (5
Four).

By performing the determination process for the presence / absence of the coin 1 in this manner, the reference value α is automatically corrected to a value corresponding to the external light incident on the passage sensor 5 at each time, and as a result, the amount of incident external light is changed. It is possible to accurately determine the presence or absence of the coin 1 in the passage sensor 5 regardless of the situation.

Further, the microcomputer 6 repeatedly executes such coin presence / absence determination processing many times in a cycle of 3 msec during 50 to 100 msec in which the coin 1 passes through the passage sensor 5, and as a result, the passage of the coin 1 is surely detected. You will be able to.

On the other hand, the microcomputer 6 deenergizes the solenoid of the coin 1 passage switching device that detects that the coin 1 has passed the passage sensor 5, closes the positive coin passage 2a entrance with the switching plate 4, and passes the passage sensor 5 forward. Processing such as counting the amount of coins by the counting means is executed.

The correction of the coin presence / absence detection reference value α is set to 1/3 of the sensor detection value V ₁ when the light emitting diode 9 is extinguished in the above embodiment, but the coefficient value K by which V ₁ is multiplied is limited to 1/3. No, 1/2.
It may be 5, 1 / 3.5, etc., and the optimum value should be determined by experiment.

FIG. 6 shows another embodiment for correcting the coin 1 presence / absence detection reference value α. In this process, first, the reference value α is set by multiplying the sensor detection value V ₁ at the time of extinction when there is no external light by a coefficient K = 1/3 (60). Next, when external light enters and the sensor detection value V ₁ changes, the sensor detection value V ₁ ′ at that time is detected and the change ratio V ₁ ′ / V ₁ is calculated (61). Then, the reference value α set previously is α ′ =
Correct to (V ₁ ′ / V ₁ ) α (62). Thereafter, 'based on, as the processing of FIG. 5, the sensor detection value V ₂ at the time of emitting' reference value alpha this that corrected to obtain V _'1 -V' ₂ <calculates the alpha (63), established If so, it is determined that there is a coin, and if not, it is determined that no coin exists. The coin passage may be detected after correcting the reference value α as described above.

(G) Effect of the Invention As described above, according to the present invention, the passage of the coin 1 is detected by comparison with the object passage detection reference value α corrected according to the amount of external light entering the sensor unit. Therefore, the passage of the coin 1 can be reliably detected regardless of the amount of external light incident on the sensor unit.

[Brief description of drawings]

FIG. 1 is an explanatory view of a coin passage in a coin sorting device showing a state of arrangement of a sensor portion of a coin passage detecting device according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of the coin passage detecting device,
FIG. 3 is a signal waveform diagram of each part in the coin passage detection device in accordance with a change in external incident light amount when no coin is present, and FIG. A signal waveform diagram, FIG. 5 is a flowchart showing a part of a coin detecting process performed by the microcomputer 6 in the coin passage detecting device, and FIG. 6 is a flowchart showing another example of the coin detecting process. 3 ... Inspection sensor, 5 ... Passage sensor, 6 ... Microcomputer, 9 ... Light emitting diode, 11
...... Phototransistor, 13 …… A / D converter.

Claims (1)

[Scope of utility model registration request] 1. An object passage detection device for detecting passage of an object using an optical sensor comprising a light emitter and a light receiver, wherein at least a certain time after the light emitter is turned off is determined according to a sensor detection value obtained from the light receiver. Means for calculating and setting an object passage detection reference value, means for calculating a deviation between the sensor detection value and a sensor detection value obtained from the light receiver after a fixed time has passed since the light emitter was turned on, and the deviation and the object An object passage detecting device, comprising: means for comparing the passage detection reference value with a passage determination reference value to determine passage of an object.