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In my earlier project I used this device as a IR Transmitter and promised to upload this project description in next instructables.

So here I present you IR Transmitter using 555 Timer.

Last project in which this remote

We want to design a astable multivibrator of 38KHz. This can be done by using 555 Timer.

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## Step 1: Schematic Diagram

In the above circuit, 555 Timer is wired as an Astable Multivibrator. The 100μF capacitor (C1) is used to reduce ripples in the power supply. 1st and 8th pins of 555 are used to give power Vcc and GND respectively. 4th pin is the reset pin which is active low input, hence it is connected to Vcc. 5th pin is the Control Voltage pin which is not used in this application, hence it is grounded via a capacitor to avoid high frequency noises through that pin. Capacitor C2, Resistors R1, R2 determines the time period of oscillation. Capacitor C2 charges to Vcc via resistors R1 and R2. It discharges through Resistor R2 and 7th pin of 555. The voltage across capacitor C2 is connected to the internal comparators via 2nd and 6th pins of 555. Output is taken from the 3ed pin of the IC. Charging time constant of the capacitor (output HIGH period) is determined by the expression 0.693(R1+R2)C2 and discharging time constant (output LOW period) is determined by 0.693R2C2. They are approximately equal.

You can use the RESET pin of 555 for transmitting binary data.

## Step 2: RequirementS

1. 9V battery( I used an old 9V battery)
2. 100uF capacitor ( optional )
3. 0.001uf capacitor
4. 0.1uf capacitor
5. 1 K resistor
6. 100 Ohms resistor
7. 20 K resistor
8. 1 or 2 IR LED's
9. Switch
10. NE555 Timer IC

## Step 3: Finished Product

these are some picture of finished product how it look alike.

I an also adding the PCB layout for those who don't want use wires.

Last project in which this remote

Hope you like it.

Note : Output frequency of above circuit is about 35.2KHz. As per our experiment TSOP1738 is detecting it but you will get more range if you use exact 38KHz. You may also use 18K resistor instead of 20K which will produce 39KHz. Better you can try a preset for accurate 38KHz.

## Step 4: Some Calculation

Since we are using this circuit in Astable mode and we need 38 khz then we have to use R1=1.025k , R2=18.47k and c1= 1nf or we can say 0.001uF. Since we can't get 18.47 k and 1.025 k resistor then we used here is 20k and 1 k resistor after using these resistor we get 35.188 khz. If we will use exact 18 K and 1 k resistors in the circuit it will give 38.992 khz. Since 5th pin is the Control Voltage pin which is not used in this application, hence it is grounded via a capacitor to avoid high frequency noises through that pin. C3=0.01uF will not going to effect on the calculation part. so you can remove it. It totally depends on you.

## Step 5: What Next

Participated in the
Digital Life 101 Challenge

Participated in the
Full Spectrum Laser Contest 2016

Participated in the

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## 30 Discussions

Hello, i am asking question not related to this project but question is regarding ir receiver circuit, which i have made using ic hcf1407, which control electrical appliances but the relay in it us automatically switching on and off how to correct it

Hey, Can I change the sending values of this circuit. And I want to add more buttons.

yes you can change the sending values and also add more buttons but for this you have to use a programmable chip like arduino

hi

i will make it today ... but what will be this range

can u reply me url of ir reciever

For receiving I used TSOP 1738 IR receiver which has around 10mtr. Range.

http://www.micropik.com/PDF/tsop17xx.pdf

You've made some cool projects! Keep it up!

I'm not sure if I under stand this or not but with this would I b about to make a dimmer or even a switch if I get a receiver and enter the right code? BTW I'm a rookie at a lot of this

6 replies

sandy 65 i did all the things tight so why not my circuit is working

Can you do one on a dimmer that shows a digital speed selection number for 110v ac motor

Do one what? 8-/

And 1 More thing why don't you just check my another project on 555 timer IC. I think you will understand the difference of this circuit and that circuit.

Ya, But I can make a dimmer circuit for DC motor of voltage 0-12V. But I will let you know that you can make it for 110V AC motor. First I have to study about the dimmer.

But you can switch ON/OFF your FAN with it

Did you really did that.. but nice joke bro.. After all photo editing I think you learnt something from my project.

Did you really did that

Did you really ask that? ;)

After all photo editing I think you learnt something from my project.

Don't worry, it was just a few minutes, but yes, I learned that obsessive placement of a clothes patch is really distracting and doesn't help at all.

Then I actually looked at your schematic... And learned that it's possible to make an error for every 2 components used.

The 100μF capacitor (C1) is used to reduce ripples in the power supply.

Why do you wanna do that and how did you select that value?

5th pin is the Control Voltage pin which is not used in this
application, hence it is grounded via a capacitor to avoid high
frequency noises through that pin.

Why do you wanna do that?

How did you select the value of R3 (and why not put it in the parts list)?

Do you honestly believe that the poor 555 will put out 250..300mA @9V?

You didn't mention using high power IR-LED(s) (guess you meant 1 to 2 IR-LEDs, rather than half a LED as you wrote), how much current do you think an average IR-LED can handle?

Given the frequency of a 555 is (ln(2) x (R1+2 x R2) x C)^-1, your 38kHz is actually 35.2kHz, which means that the range is roughly halved - What changes will it take to get the frequency right?

If you go read the datasheet of the 555 and that of the IR-LED you used and then try to answer the questions I put forward, there's a good chance that you might learn a thing or two!

Oh, BTW. the TSOP1738 that you want to use at the receiving end is not made for CW

Quoting from the datasheet:

Some examples for such disturbance signals which
are suppressed
by the TSOP17.. are:
• DC light (e.g. from tungsten bulb or sunlight)
Continuous signal at 38kHz or at any other
frequency
• Signals from fluorescent lamps with electronic
ballast (an example of the signal modulation is in the
figure below).

Special IR receivers exists for CW (like e.g. TSSP4038).

To use TSOP17nn, the signal should be modulated like this:

Again from datasheet

The data signal should fullfill the following condition:
• Carrier frequency should be close to center
frequency of the bandpass (e.g. 38kHz).
• Burst length should be 10 cycles/burst or longer.
• After each burst which is between 10 cycles and 70
cycles a gap time of at least 14 cycles is neccessary.
• For each burst which is longer than 1.8ms a
corresponding gap time is necessary at some time in
the data stream. This gap time should have at least
same length as the burst.

• Up to 1400 short bursts per second can be received
continuously.

The effect of this is, that a continuous signal lasting more than 1.84ms is considered noise, and makes the receiver turn its sensitivity more and more down, until it sees a break and that means a serious loss of range (which is up to 35m when used correctly). Add to that, the wrong frequency that steals around half the signal in the first place and I begin to wonder if that's the reason that you torture both the LED and the 555?!