# Object detector using ultrasonic sensor with 555 timer

• engnrshyckh
In summary, the conversation discusses the use of a 555 timer and a distance sensor in a circuit. The speaker used a 220uF and 10uF capacitor, but the buzzer was not loud enough. They also tried changing the resistance of the potentiometer, but the buzzer still wasn't loud enough. The speaker mentions that the 3.3pF capacitor is too small and suggests using a 470pF minimum. They also note that the sensor in the attached figure is an ultrasonic distance sensor that may require a comparator for maximum range. Finally, they mention a comment from the sensor's datasheet about the necessary conditions for accurate measurements.
engnrshyckh
TL;DR Summary
I am doing a simple project in which i want to detect object using 555 timer and ultrasonic sensor.
See the attached figure.
I used 220uF with buzzer and also tried 10uF capacitor but buzzer isn't loud enough. I don't have any 3.3pf capacitor. I used 1.1 pF instead. I also tried changing the resistance of potentiometer but still buzzer isn't sound loud enough.

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The 3.3 pF capacitor is much too small for a 555 oscillator.
frequency = 1.46 / ( (R1 + 2*R2) * C )
C = 1.46 / ( 5kHz * ( 10k + 2*1k) ) = 24 nF

Fisherman199 and BvU
Baluncore said:
The 3.3 pF capacitor is much too small for a 555 oscillator.
frequency = 1.46 / ( (R1 + 2*R2) * C )
C = 1.46 / ( 5kHz * ( 10k + 2*1k) ) = 24 nF
I don't have such values of capacitance can i change the value of R2 FOR fixed value of C i. I 3.3pF

engnrshyckh said:
I don't have such values of capacitance can i change the value of R2 FOR fixed value of C i. I 3.3pF
I have no idea what you are suggesting there.

If I remember correctly, the 555 needs a timing capacitor of 470pF minimum.
The 3.3pF is not useful anywhere in the circuit. I do not know why the website showed that value on the schematic. If you look in the parts list, you will see it specifies a 3.3nF capacitor. That is a better choice.

I computed a timing capacitor value of about 24nF. The closest available value will probably be 22nF. Try any value of capacitance you can find between (1nF = 0.001uF) and (100nF = 0.1uF).

https://en.wikipedia.org/wiki/555_timer_IC#Astable

Fisherman199, DaveE and hutchphd
Windadct said:
- the sensor in your image looks like a Ultrasonic DISTANCE sensor -
If there is no reflector within range in the 15° beam, then it does not produce a detection pulse, so it may be used as a detector without range.

Windadct said:
Asside from the 555 issues - the sensor in your image looks like a Ultrasonic DISTANCE sensor -

https://www.sparkfun.com/products/15569

This needs more then a timer.
Yes it is so may be a commarotor will work

Yes, a comparator will likely work.

Although likely needed only for the maximum range of 4 meters, please note the comment on page 3 of the datasheet:
(bold added)
When tested objects, the range of area is not less than 0.5 square meters and the plane requests as smooth as possible, otherwise, it will affect the
results of measuring.

Cheers,
Tom

## 1. How does an ultrasonic sensor detect objects?

An ultrasonic sensor emits high-frequency sound waves and measures the time it takes for the waves to bounce back off of an object. The sensor then calculates the distance to the object based on the speed of sound.

## 2. What is the purpose of using a 555 timer in an object detector?

A 555 timer is used as a pulse generator to trigger the ultrasonic sensor to emit sound waves and receive the echoes. It also helps to control the timing and sensitivity of the sensor.

## 3. Can an object detector using ultrasonic sensor with 555 timer detect multiple objects at once?

Yes, an object detector using ultrasonic sensor with 555 timer can detect multiple objects at once. However, the accuracy of the distance measurement may be affected if there are multiple objects in close proximity to each other.

## 4. How accurate is an object detector using ultrasonic sensor with 555 timer?

The accuracy of an object detector using ultrasonic sensor with 555 timer depends on various factors such as the quality of the sensor, the environment, and the circuit design. Generally, it can provide a distance measurement accuracy of up to 1 cm.

## 5. Can an object detector using ultrasonic sensor with 555 timer be used in any environment?

An object detector using ultrasonic sensor with 555 timer can be used in most environments, but it may face challenges in highly reflective or absorbent surfaces. It is also not suitable for use in extremely noisy or windy environments as it may affect the accuracy of the distance measurement.

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