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[SOLVED] 38Khz transsmitter circuit need help here

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how to generate 38 khz frequency

Any wedside can recommend? which is safe to be use...for project purpose!
 

38khz signal

Most electronic products already have IR remote control so not many people make a circuit.
Try looking in Google for a modern circuit that works well.
 

ir 38khz led peak current

Anyone knows how to modulate 38KHz Infra Red transmitter using Microchip PIC12f609 or 16f883 ?
thanks for help
 

38khz 555 schematic

guesslsc85 said:
Anyone knows how to modulate 38KHz Infra Red transmitter using Microchip PIC12f609 or 16f883 ?
thanks for help
Click to expand...
If your mcu has pwm function,you can use it. set the pwm frequency at 38khz and a proper duty is ok.For example 1/3.Then you can drive the IR led with a larger current than the spec and get more transient power radation. With the 2 port and(&)function,one port is your baseband low speed data(lower than 1-2kbps),the other is the PWM signal.Then the output can be used to drive the IR led.If you want to get longer distance,maybe a transistor buffer and high sensitive receiver module are needed.
 

38khz trasmitter

Could you help to show some codes in HiTech lite C language on how to generate 38KHz pulses using PIC16F883 chip or its family.

Thanks for helping.
 

generate 38khz ir

Ah blast HiTech C for pete's sake. Use something better like CCS.

HiTech is only for people how could have coded in ASM right off their fingers but their clients want the code in C.

CCS is for hobbyists. Like you and me.

You will get READY TO GO code for what you want on CCS forum.
 

555 38 khz

i found a IR circuit in this link
https://electroschematics.com/782/infrared-light-barrier/

it seems to be fine, because the IR LED can be transmmit in higher current support by the Transistor.
i hope so!

The receiver module is using TSOP1836 if i change it to TSOP1838 can it work?
and i need opinion in this design TQ
 

remote control 38 khz

only a little difference in carrier frequency.you can adjust the 555 oscillating frequency.
 

38 khz remote control circuit

Finally a designer has read the IR-receiver datasheet and understood, that the 38 kHz signal must be send in bursts or "chopped" to achieve high sensitivity. Unbelievable!

Follow this circuit, place your original design into the trashcan.
 

schematic tsop1838

FvM said:
Finally a designer has read the IR-receiver datasheet and understood, that the 38 kHz signal must be send in bursts or "chopped" to achieve high sensitivity. Unbelievable!
Click to expand...
But the bursts are at a frequency that is too high for the TSOP1838. The OFF time must be 15ms or more. Each TSOP needs a different burst frequency.
 

    E

    ericyeoh

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tsop1838 schematic

well the original 38khz circuit is done and test the distance can only acheive to 60cm. the receiver i using TSOP4138 and the IR emitter LED i just simply buy 2mm size.

The current through the LED is 65mA, wonder why the voltage through the LED only 0.7V.

The output of the 555 is rather low 2.1V only so the voltage across the 22ohm resistor is measure ~1.4V

But i replace another type of IR emitter, the distance can receive is defferent. But also cannot radiate more than 60cm
 

38 khz ccsc code software

I think the clue here is that you measure 0.7V across the LED.
How are you measuring it? You need an oscilloscope to truly measure it, if you use a normal voltmeter, it will only see approximately the average voltage and current. It wont take into account that it isn't constant and probably half the time is in an off state.

Brian.
 

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    ericyeoh

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infrared barrier circuit project

We should not rely on the result of DMM.Because DMM's bandwidth is only hundreds of Hz.You can see the waveform on the oscilloscope.
you distance is so short.there is no 2mm IR diode,maybe you refer to the 3mm diameter? 65mA peak current is big enough.
 

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    ericyeoh

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how to generate 38 khz signal

I see two points:
- Without an oscilloscope, you also won't be able to verify the correct carrier frequency of 38 kHz. By using a variable resistor, you can adjust the carrier frequency for maximum operation distance instead.

- As mentioned by Audioguru and others, remote control receivers are designed to suppress unmodulated 38 kHz IR carrier signals. Unfortunately, I don't know what's the sensitivity advantage with a chopped carrier. But you should give it a try.
 

    E

    ericyeoh

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pic micochip ccs irda 38khz

By using the oscilloscrope to measure the output of the 555 , the carrier frequency is ~~35khz
 

+555 +38khz

reduce the resistor between pin 7 and 6 a little until you get the transmiting carrier frequency 38k.
 

    E

    ericyeoh

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;ve try to reflected the infrared signal by using a mirror to the TSOP receiver, by it failed..
Guys..Any opinion on how can i reflect the signal and the Receiver still can get the signal?
 

How did you manage not to reflect near IR? Any metallic mirror does.
 

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