JPH01221690A - Ultrasonic distance sensor - Google Patents

Abstract

PURPOSE:To adjust the number of times of extraction by extracting and outputting data by a sampling gate when a distance detecting means outputs too many data signals. CONSTITUTION:A proper voltage is applied to an A/D conversion part 5 by adjusting a variable resistor 4a and a microcomputer 5 is started. The conversion part 5a sets a digital value in a presettable counter 5b. A tone burst signal which is generated by an ultrasonic wave emitting circuit 2 is transmitted as ultrasonic wave pulses by an ultrasonic vibrator 1. A reflected wave from an object body is received by a vibrator 1 and electric pulses are amplified by a receiving circuit 3 and sent to the microcomputer 5. The microcomputer 5 subtracts one from a counted value set in a counter 5b. Therefore, when a voltage applied to a conversion part 4a is high and the digital value preset in the counter 5b is large, the output period of distance data becomes long. Consequently, the number of times of extraction is adjustable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic distance sensor that detects the distance to a target object using the propagation time of ultrasonic pulses.

[Conventional technology]

An ultrasonic pulse is emitted from an ultrasonic transducer in the direction of a target object, and the ultrasonic pulse hits the target object, is reflected, and returns to the original ultrasonic transducer,
Each time this ultrasonic pulse is emitted, we measure the time from the time the ultrasonic pulse is emitted until the reflected wave is received by the original ultrasonic transducer, and calculate the distance from the ultrasonic transducer to the target object. An ultrasonic distance sensor that detects distance data and outputs this distance data is known.

[Problem to be solved by the invention]

The above-mentioned ultrasonic distance sensor detects the distance to the target object every time the ultrasonic transducer emits an ultrasonic pulse and outputs this data, so depending on the combination of the ultrasonic distance sensor and the distance of the target object, The disadvantage is that the number of detections is large and the output is too dense.

An object of the present invention is to provide an ultrasonic distance sensor in which the sampling interval can be adjusted externally and the output cycle can be changed.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention periodically emits ultrasonic pulses, measures the time until the ultrasonic pulse hits a target object, is reflected, and returns to the emission point of the ultrasonic wave, In an ultrasonic distance sensor that includes distance detection means for detecting the distance to a target object from the measurement data each time, and outputs the distance detected by the distance detection means as a positive value, the distance detection means detects the data. extract,
A sampling gate whose extraction period can be adjusted is provided.

[Effect]

In the present invention, when there are too many data signals output from the distance detecting means, this data is extracted and output by a sampling gate, and the number of times of extraction can be adjusted.

〔Example〕

An embodiment of the present invention will be described based on the wiring diagram shown in FIG. Here, the ultrasonic distance sensor consists of an ultrasonic transducer 1, an ultrasonic emitting circuit 2, an ultrasonic receiving circuit 3, a DC power source 4, and a variable resistor 4as one-chip micro combinator that makes the voltage of the DC power source 4 variable. (hereinafter simply referred to as microcomputer)
5. The ultrasonic emitting circuit 2, which includes an output circuit 6 and the like, is connected to oscillate an ultrasonic frequency according to a command from a microcomputer 5, and emit an ultrasonic pulse from an ultrasonic transducer l. The ultrasonic receiving circuit 3 is connected so that the ultrasonic transducer l converts the received ultrasonic pulse into an electric pulse, amplifies it, and inputs the amplified ultrasonic pulse to the microcomputer 5. In addition to ROM and RAM, the microcomputer 5 also has an analog-to-digital conversion section (hereinafter referred to as A/D conversion section) 5.
Equipped with a1 preset counter 5b, etc., it controls each part and calculates the time until the ultrasonic pulse emitted from the ultrasonic transducer 1 hits the target object and reaches the ultrasonic transducer 1 again, and calculates the distance. Convert. In other words, microcomputer 1
serves as a distance detection means. Also, A/D of microcomputer 5
The converter 5a converts the voltage applied from the power source 4 to the variable resistor 4.
The voltage adjusted by a is converted into a digital value and set in the preset counter 5b. The output cycle is determined by the magnitude of this set digital value. That is, the power supply 4, the variable resistor 4a, the A/D converter 5as, and the preset counter 5b serve as a sampling gate.

The operation of this ultrasonic distance sensor will be explained below with reference to the flowchart shown in FIG. The S numbers in FIG. 2 indicate the numbers of each step in the flowchart.
A is adjusted to apply an appropriate voltage to the A/D converter 5a,
Start microcomputer 5. The A/Di converter 5a converts the applied analog voltage adjusted by the variable resistor 4a into a digital value (S1), sets this digital value in the preset counter 5b (S2), and then converts the applied analog voltage into a digital value (S2). The tone bust signal created in step 2 is sent to ultrasonic transducer 1.
The reflected wave from the target object is emitted as an ultrasonic pulse (S3), and the reflected wave from the target object is received by the ultrasonic transducer l, converted into an electric pulse, and this electric pulse is amplified by the delivery circuit 3, and the microcomputer 5
(S4), and if there is no reception signal at this time, the process is repeated until a delivery signal is received. When the microcomputer 5 receives the delivery signal as an electric pulse, it converts it into a distance based on the time from the time of ultrasonic emission, and uses this output signal to subtract 1 from the count value set in the counter 5b (S6), and converts this count value by 1. The operation of subtracting the distance is performed every time an electric pulse is input and the distance is converted, and continues until the counter value of the counter 5b reaches 0, and confirms that the counter value is 0 (s
7) and output the distance data by sending a signal to the output circuit 6.
(s8) Therefore, if the voltage applied to the A/D converter 4a is high and the number of digital values preset in the counter 5b is large, the output cycle of distance data becomes long. That is, the cycle of distance data output can be adjusted from the outside.

〔Effect of the invention〕

According to the present invention, since the output synchronization can be adjusted by adjusting and applying a voltage from the outside, it is possible to provide an ultrasonic distance sensor that can precisely detect a wide range of distances according to the distance of a detection target with one sensor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the ultrasonic distance sensor according to the present invention, and FIG. 2 is a flowchart showing the operation of the ultrasonic distance sensor of FIG. 4: DC power supply, 4a; variable resistor, 58 microcomputer, 5a
: A/D converter, 5b; preset counter. ″5

Claims (1)

[Claims] 1) Periodically emit ultrasonic pulses, measure the time it takes for this ultrasonic pulse to hit the target object, be reflected, and return to the emission point of the ultrasonic wave, and each time measure the distance from the measured data to the target object. The ultrasonic distance sensor is equipped with a distance detecting means for detecting a distance, and outputs the distance detected by the distance detecting means as a voltage value, the data detected by the distance detecting means is extracted, and the extraction period is adjustable. An ultrasonic distance sensor characterized by having a sampling gate.