In this lesson, we will introduce the 555 Timer Integrated Circuit (IC). 555 Timer IC is one of the commonly used IC among students and hobbyists. There are a lot of applications of this IC, mostly used as vibrators like, ASTABLE MULTIVIBRATOR, MONOSTABLE MULTIVIBRATOR and BISTABLE MULTIVIBRATOR. You can find here some interesting circuits based on 555 Timer IC and the Osoyoo Uno boards.
The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element.
The 555 timer which gets its name from the three 5kΩ resistors it uses to generate the two comparators reference voltage, is a very cheap, popular and useful precision timing device that can act as either a simple timer to generate single pulses or long time delays, or as a relaxation oscillator producing stabilized waveforms of varying duty cycles from 50 to 100%.
The 555 timer chip is extremely robust and stable 8-pin device that can be operated either as a very accurate Monostable, Bistable or Astable Multivibrator to produce a variety of applications such as one-shot or delay timers, pulse generation, LED and lamp flashers, alarms and tone generation, logic clocks, frequency division, power supplies and converters etc, in fact any circuit that requires some form of time control as the list is endless.
A simplified “block diagram” representing the internal circuitry of the 555 timer is given below with a brief explanation of each of its connecting pins to help provide a clearer understanding of how it works.
We will go over the pinout of the 555 timer. The 555 timer is an 8-pin IC.This means it has 8 different pins, each of which have different functions for the IC.
IC555 has three different operating modes. These operating modes actually correspond to three different multivibrator configurations.
If you want to get more info about this IC, please check this link.
In this example, the Osoyoo Uno board is used to test the frequencies of square waves generated by the 555 oscillating circuit and show them on Serial Monitor.
Build the circuit as below:
After above operations are completed, connect the Arduino board to your computer using the USB cable. The green power LED (labelled PWR) should go on. Load up the following sketch onto your Arduino.
int pin = 7; //pin 7 connected to the third pin of NE555 unsigned long duration; //the variable to store the length of the pulse void setup() { pinMode(pin, INPUT); //set the pin as an input Serial.begin(9600); // start serial port at 9600 bps } void loop() { duration = pulseIn(pin, HIGH); //Reads a pulse on pin Serial.print(duration); //print the length of the pulse on the serial monitor Serial.println(); //print an blank on serial monitor delay(500); //wait for 500 ms }
A few seconds after the upload finishes, open the serial monitor,you can see that if you rotate the potentiometer:
The length of the pulse (in microsecond) displayed will change accordingly.
DownLoad Url osoyoo.com
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part list is not the one relevant for this 555 example, where can I get the correct part list?
which learning kit you purchased? Can you show us the purchase link?
I purchased Adevanced Starter Kit for Arduino V2.
What is the function of the capacitors in this project, please?
capacitor is recommend by Timer module. If you don’t have capacitor, it should be ok. but Timer might not accurate.