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transmit and receive IR

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gunnerunbeaten

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i have to do a project, transmit and receive IR , don't use MCU + IR IC. only use IC to do it ? i don't understand principles to transmit and receive ?? please help me , what IC i can use ???:cry:
 

do you want to send and receive IR as sensor..... or want to use as data transmitter like remote control

for senor i think the best one to be used is the IR of laser mouse in it you have two IR transmitter and two for receive ...but it is small range

for data (poor knowledge)

talking about remote control every button ha certain frequency adjusted pressing say '1' then frequency is send and it is received at the receiver and frequency determined (you must make sure about this knowledge)
 
MahmoudHassan said:
do you want to send and receive IR as sensor..... or want to use as data transmitter like remote control

for senor i think the best one to be used is the IR of laser mouse in it you have two IR transmitter and two for receive ...but it is small range

for data (poor knowledge)
talking about remote control every button ha certain frequency adjusted pressing say '1' then frequency is send and it is received at the receiver and frequency determined (you must make sure about this knowledge)
Click to expand...
it's remote 8 channel... i think i use 8 switch + mux 74153 + NE 555 for transmit module, is it ok ??? how do you think?
 

An 'ls123 from memory is a timer, some infra red recivers are monolithic, they have amplifier and tone detector circuitry built in, so they can be connected directly to a logic device like the '123.
Might be worth looking in a scrap telly or video, the ir receiver is usually behind the display panel, a auick search on google will get a datasheet for it.
 
you can use TSOP1738 IR receiver module for receiving 38Khz modulated IR signal...
For that purpose, you need to make an astable multivibrator in transmitter section. Then use amplitude shift keying .I mean just switch the 38khz astable multivibrator according to your binary data. Then that data will be send to the TSOP and receive it at tsop output. It is an active low device. I mean WHILE 38khz blinking ir signal is falling on it then its output pin will be LOW. Otherwise it will be HIGH.
 
Last edited:
do you have circuit that connected shift keying to astable multivibrator???
 

friend just design an astable multivibrator using 555 ic. Its frequency should be 38khz. For that you can use variable resistor according to your design. Then connect an IR led at output of 555(connect 47ohm resistor in series) . Better use a 5 v regulated power supply to 555 so that the output frequency will be maintained constant . Pin number 4 is the reset pin of 555 which is usually connected to positive which will enable the output of 555 . So in your case WHILE you give +ve 5 volt to that pin then 38khz modulated IR Signal will be generated at the IR led. While that reset pin is given 0 volt then no IR signal is generated...So now you understood how to send your data '0' and '1' given in reset pin (4) of 555 ic.
Now you want to receive it in TSOP1738 module.
I will give you a circuit diagram for this soon. Now i cant because i am replying through my mobile . When i use my PC then i will design and draw a circuit for this purpose.
 
And also, remember for better working ,the message signal(given at reset pin of 555) frequency should be less than 2Khz with almost 50percent dutycycle.
This is because a considerable amount of 38khz cycles (a burst) is needed for successive detection of that 38khz in the receiver module.(tsop).
It is about 10cycles (ie a burst equals to a minimum of 26x10uS duration ie a logic high at reset pin should be maintained atleast 260uS)
Similarly if a logic 0 is to be send then hold the 0 at reset pin for atleast 260uS. (this is the minimum time and you could select maximum time according to your need)
 

FROM THE 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.

Some examples for suitable data format are:
NEC Code, Toshiba Micom Format, Sharp Code, RC5
Code, RC6 Code, R–2000 Code, Sony Format
(SIRCS).
When a disturbance signal is applied to the TSOP17..
it can still receive the data signal. However the
sensitivity is reduced to that level that no unexpected
pulses will occure.
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
http://www.datasheetcatalog.org/datasheets/208/301092_DS.pdf
 
Last edited:

So for a 38khz fO, a burst length should be at least 263uS and a gap time of 368uS?

or...263uS HIGH, 368uS LOW then cycle....

Here is my setup..

97d83e0028e27d66305731ac425b799f0bb3792f3db67cf61bb7605c6d4f99226g.jpg



BR
 

First 555(message)
Frequency: 1.815 KHz Cycle Time: 550.935 μs
Duty Cycle: 50.94 %
Time High: 280.665 μs Time Low: 270.270 μs
(so adjust little bit to satisfy the minimum requirement)
second 555:(carrier)
Time High: 831.600 ns Time Low: 12474 ns
frequency = 76Khz
So it will not work.


so better u do one thing:
1>Remove that diode .
2>use R1=4.7K
3>use R2=16.637K (not possible, so use 10k fixed resistor + 10k variavle resistor and adjust it to get required value)
4>use c2 & c4 as .01uF instead of .1uf.

Want instant calculation of frequency, dutycycle, Time high, Time low ,Timeperiod in a web page? :?:
An interesting java script 555 astable calculator:(must visit)
:arrow:555 Astable Circuit Calculator
 
Last edited:

vinodstanur said:
...
second 555:(carrier)
Time High: 831.600 ns Time Low: 12474 ns
frequency = 76Khz
So it will not work.
Click to expand...


I wonder how you came up with 76Khz?

R3= 1.2K
R4 = 18K
C3 = 0.001uF


Based on the calculator you've posted:

Frequency = 38.790 KHz
Duty Cycle = 51.61 %
Time High = 13.306 μs
Time Low = 12.474 μs
Cycle Time = 25.780 μs
 

U are using a diode D3 in parallel withR4.
So while charging capacitor, R4 is short circuited (ideally) by diode.
So R3 and C2 decides charging time.
T charging=.693 x R3xC3 = .693*1200*.000000001 = 831.6ns

Now While discharging, PIN 7 of 555 is grounded by an internal transistor.
So pin7 voltage is ZERO.
Now diode is reverse biased.(charged cap voltage at cathode and groung at anode)
So it act as open circuit.
So discharging is done through R4 .
ie
T discharging =0.693 x R3xC3 = .693*18000*.000000001 = 12474ns

so ADD both and find T total.
f=1/T total = 76Khz


In ur circuit u can just remove that Diode to make it 38Khz.

---------- Post added at 08:55 ---------- Previous post was at 08:36 ----------

Circuit Simulator Applet

---------- Post added at 08:57 ---------- Previous post was at 08:55 ----------

click above link for online circuit simulation of ur circuit and note the frequency.
 

so weird!

I removed the diode and my IR receiver will only detect a maximum of 6" and take note..it is NOT continues anymore...the LED connected at the output will only blink for a while then no more..i have to remove my hand again and wave...:(

But with diode installed it can detect up to 1.5 ft and as long that my hand is in front the LED will continue to light....
 

Had u connected a decoupling capacitor near TSOP 5v supply pins? A 100E resistor in series with TSOP 5v SUPPLY?

---------- Post added at 09:56 ---------- Previous post was at 09:48 ----------

AND are u sure that ur TSOP is 38kHz ? All TSOPs are not 38kHz ....
 

Here is the schematic of my IR receiver:


attachment.php



Here is the datasheet of my IR module:

sm3386.pdf
 

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Last edited:

MahmoudHassan said:
do you want to send and receive IR as sensor..... or want to use as data transmitter like remote control

for senor i think the best one to be used is the IR of laser mouse in it you have two IR transmitter and two for receive ...but it is small range

for data (poor knowledge)

talking about remote control every button ha certain frequency adjusted pressing say '1' then frequency is send and it is received at the receiver and frequency determined (you must make sure about this knowledge)
Click to expand...

what you have explained is of vital importance and useful ...i can make use of it into my cargps
 

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