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.

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.

Remote Control Circutre.pdf
Download

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.