# how! a infrared 'transmitter'



## sourav (Sep 22, 2007)

*how! to make a infrared 'transmitter'*

i want to use a remote controller of a device from another room which is far away.

is their anyway?  please sugget.

i think we can take a infrared receptor & infrared bulb. I know infrared receptors are available at stores. We have to make make a circuit through which we can utilise this to control other devices.

e.g-:> I mean I have tatasky located in one bedroom with the tv. it is connected to computer through rf(cable line) and to the tv with audio video channel available. I want to control the tatasky while watching it on tatasky.

I hope u understand my question

pls help


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## iMav (Sep 22, 2007)

setup a mirror arrangement to relay the infra red .... but i doubt the possibility to achieve somehting like this ...


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## abinesh (Sep 22, 2007)

bro... i dont think you can use IR for transmission from aroom to another. its usually point to point communicator and from room to room ... no way !! yea... may be mirror arrangement might work ( im not sure ) . 

but you could use a bluetooth transmitter ... the ics are available ... but this project migt turn out costly !!


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## sourav (Sep 22, 2007)

think i press a switch on the remote of tatasky while sitting near the computer. By having a receptor in that room, connected to a a circuit which boosts the signal and sends that signal (through wires)  to the room where it is located. And keeping a infrared bulb infront of the the tatasky, so that when i press the key to change the channel, it transmits the data to that bulb located infront of the tatasky can change the channel by transmitting the same signal.

What do u think ???

oye help karo


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## indian_samosa (Sep 22, 2007)

I actually wanted to setup something similar.I have DishTV in the drawing room and have the audio and video cables from the Settop box to the tv tuner in the bedroom.I think the following might work ....

You can get a infrared transmitter the same as the one in your remote and place it directly infront of the Settop box's infrared receiver.Now connect the wires from the transmitter to the infrared tarnsmitter on ur remote.I am talking about a parallel connection.It should work I suppose and will not need any extra boosting.What basically u r doing is extending the remote transmitter to beyond its original length.

Now I havent tried it ..... But wish to in the future.

I ll try it on monday .....lets see


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## iMav (Sep 22, 2007)

^^ better than that .... remove the ir transmittter frm the remote ... connect to a wire and place it in front of ur set top box ....


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## sourav (Sep 22, 2007)

now think again,

it will need electricity to provide reception of remote signal and transmit it to the bulb.

so, their is a need of circuit system. i want to know on how to make that circuit.


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## iMav (Sep 22, 2007)

it will work on the power by the remote only ....


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## sourav (Sep 22, 2007)

i don't want to open the remote and place.



> think i press a switch on the remote of tatasky while sitting near the computer. By having a receptor in that room, connected to a a circuit which boosts the signal and sends that signal (through wires) to the room where it is located



i want remote and the receptor should not be connected by wires


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## indian_samosa (Sep 22, 2007)

iMav said:
			
		

> ^^ better than that .... remove the ir transmittter frm the remote ... connect to a wire and place it in front of ur set top box ....



yup that also will do .... But Khali-pili why to remove the nice transmitter on the remote !!


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## sourav (Sep 22, 2007)

^^ i agreehow can u remove it from it! (don't ans this question)

we need a ciruit

help me plz


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## iMav (Sep 22, 2007)

circuit for what dude  making a power ckt for a ir tx wont help at all

u need to relay the signal coming from the remote


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## infra_red_dude (Sep 22, 2007)

first of all you can just take a transmitter and connect it to the receiver by a simple wire. you require a modulating circuit to convert the IR signal to electrical signals and then back to IR signals. this aint an easy job man! i don't think working that much wud be viable. IR needs line of sight. a major drawback. this is the reason why IR is not popular (yeah mebbe even me!!  )


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## sourav (Sep 22, 2007)

i mean that only

i want to relay signal but i don't want to open the remote make relay connection. So, their is a need of a circuit which accepta the signal and send to the bulb for this it also need electricity

so whatever u can call it but i can't open my remote as it will make the remote look bad and it will not be allowed by my family and this will also hamper warranty

@infra
but i have to use this all remote suport IR only


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## iMav (Sep 22, 2007)

nahi chalega bhai ... ir relay cant be done at home ....


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## sourav (Sep 22, 2007)

plz help


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## Pathik (Sep 22, 2007)

the best option wd be to use an array of mirrors.. Position them such that the signal get reflected directly onto the receiver.


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## Pathik (Sep 22, 2007)

the best option wd be to use an array of mirrors.. Position them such that the signal get reflected directly onto the receiver.


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## sourav (Sep 22, 2007)

nothing is impossible

just changing of the IR signals are done in tv on anything which uses remote

so, their should be a wayout, i want just a circuit diagram

off topic
are there any electrical engg or students here


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## Kenshin (Sep 22, 2007)

get the ir signals modulate them use a RF transmitter ....receive the RF signals by a receiver demodulate...giveem to the IRLED simple....will work in 200 mtr range.....will cost u 600 bucks tho.Am a electronics engg student...rt now am doin a project on transmiting temperatures from 6 different points thru a microcontrolled RF transmitters to a PC.


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## infra_red_dude (Sep 22, 2007)

you don't need to open up the remote. you need to get a set of IR transmitter and receiver. then you need to wire them up wid 2 circuits. the receiver is connected to the circuit which converts IR signals to electrical pulses. this sits near ur computer. the output of this circuit goes to the input of another circuit which converts electrical signals to IR signals connected to the transmitter which sits in front of the IR receiver on the set top box. yes, the whole circuit will require power, DC power (mebbe an adapter or batteries). 

but believe me, its not easy to build this circuit. jus go out in the market and launch a hunt for those kindsa circuits.


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## Kenshin (Sep 22, 2007)

^^ That will be messy stuff.....its cheap but its no good...i hv worked with IRs and they are no fun to work with....tats why now i hv shifted to RF in all my works...except linefollowers and to control my PC ka apps using tv remote hehe


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## sourav (Sep 22, 2007)

can u plz give a circuit diagram as i unable to make out

how to modulate and demodulate ir signals to rf and vice versa


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## infra_red_dude (Sep 22, 2007)

^^^ you get readymade circuits for that.

@yeah kenshin, i kno that too. am an electrical and electronics engg. plus hey i'm the IR of this forum!!!  who better can know the pains associated wid me!!! haha...


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## sourav (Sep 22, 2007)

@infra
that is what i want

i don't want to make the circuit but just wanted this working

do u know, what are those circuits called

are they available in any electrical stores

can u also give the circuit diagram of connecting the battery, those circuits, transmitter and receiver


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## infra_red_dude (Sep 22, 2007)

well, i can't say where they are available or how easily. you gotta hunt for them or get them made from the electronics hub in ur city.


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## Kenshin (Sep 22, 2007)

Get a TSOP1738....since most IR remotes work at 38KHz...this receiver has 3 pins...one of it is the data...give this data pin to a rf transmitter TX433...

this will transmit the data......recive the data using RX433

this has a data pin...give it to a IR led infront o ur tata sky.......press ur remote see it work ..

the RF modules will cost u bout 500 bucks...


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## infra_red_dude (Sep 22, 2007)

kenshin forgot the IR transmitter on the other end. so add that


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## Kenshin (Sep 22, 2007)

Yeah a transmitter from the data pin...


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## sourav (Sep 22, 2007)

you mean that i will connect receiver's data channel to transmitter's???

if yes, then what are those other 2 point for, where they will be connected and how

then what about connecting the data pin directly to the data pin of transmitter


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## Kenshin (Sep 22, 2007)

Have a look at this 
attachment


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## sourav (Sep 22, 2007)

and where the batteries should be connected


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## infra_red_dude (Sep 22, 2007)

Vcc and GND pins are where the battery will be connected. +ve to Vcc and -ve to GND. that BC547 is the transistor there which works as a switch in CE mode. it activates the IR transmitter only when it gets a signal from the RF receiver, so that false triggering is prevented.

btw, just check what battery rating is to be used from the datasheets kenshin has mentioned. too high a value will make the circuit go straight into the bin!!


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## sourav (Sep 22, 2007)

@kenshin i understoodit but is there a no need of using rf when it is located in thenext room, i would prefer wires as it would be cheap but i want to understand ur idea


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## Kenshin (Sep 22, 2007)

Ok remove the RF modules connect the output of the TSOP thru a wire to the transistor in the other room tat will work...batteries depend on the length of the wire...greater the length more power will be required to drive the line..


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## sourav (Sep 22, 2007)

thankyou kenshin 

that means u agree to my decision, should I use 5v as minimum and maximum for any length of wire

and should i connect both of them to same source of powwer


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## Kenshin (Sep 22, 2007)

yes both of them shud hv same power supply.....so tat makes 3 wires,Vcc,Gnd and data..yeah a 5v supply will do.


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## sourav (Sep 22, 2007)

i mean that both the gnd to gnd to -ve and other two to positive

thankyou for ur help

a lot of thanks


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## indian_samosa (Sep 23, 2007)

Kenshin .... bloody awesome man !! ...


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## Pathik (Sep 23, 2007)

@kenshin is that temp thing ur final year project??
@infra wat did u make in ur final year??


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## infra_red_dude (Sep 23, 2007)

@pathiks

we worked on a high voltage project and used some FEM software for analysis.

@saurav
i'd still suggest you go wid the RF combo rather than a pure wired one. IR has given me huge hassels this way.


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## Kenshin (Sep 23, 2007)

nah its not my final yr project rt now this is timepass project.....previously i made a encoded 8 4 bit data transmission thru RF....so tot of makin temperature as the data and to make it more fun....takin 6 temperatures and modulatin on single freq thru a microcontroller...will be using atmega32 or 16....


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## iMav (Sep 23, 2007)

convert ir to rf and then send but im still not sure whether when volume is increased the volume will increase


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## Kenshin (Sep 23, 2007)

infra_red_dude said:
			
		

> @pathiks
> 
> we worked on a high voltage project and used some FEM software for analysis.
> 
> ...




+1 for tat .....



			
				iMav said:
			
		

> convert ir to rf and then send but im still not sure whether when volume is increased the volume will increase




tats why i told to use a TSOP...it has a inbuilt modulator which modulates the freq so the data is preserved...


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## infra_red_dude (Sep 23, 2007)

^^^ hey i meant infra red combo, not ME!!!   

hehe....


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## Kenshin (Sep 23, 2007)

Rt now i also hv got a problem....the new version of AVRdude doesn't seem to run on vista...runs perfectly fine on Ubuntu and XP....any idea about tat


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## infra_red_dude (Sep 23, 2007)

bro, in this front vista has given me lotsa probs. thats why i shifted back to XP. no point in breaking the head solving these compatibility probs.


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## Kenshin (Sep 23, 2007)

so better off with ubuntu i guess..


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## Pathik (Sep 23, 2007)

hey hows winavr compared to avrdude??


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## sourav (Sep 23, 2007)

ok ther are hassels with IR, OK

wil it give a lot hasssls when i am for only this use

as my motherboard supports for 4 usb in front panel but in front their two are located. and suppport for two are there, there are many point, i found the gnd one, but i am not to which +ve one should i use


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## Kenshin (Sep 23, 2007)

pathiks said:
			
		

> hey hows winavr compared to avrdude??


winavr uses avrdude to dump.........it just provides a gui
I hv started using codevisionAVR...i liked the wizard feature..

and most tools i got for avr were in the ubuntu repositories...just searched for avr in the package manager and got lots of great tools never knew of them...hehe



			
				sourav said:
			
		

> ok ther are hassels with IR, OK
> 
> wil it give a lot hasssls when i am for only this use
> 
> as my motherboard supports for 4 usb in front panel but in front their two are located. and suppport for two are there, there are many point, *i found the gnd one, but i am not to which +ve one should i use*


*pinouts.ws/usb-pinout.html


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## sourav (Sep 23, 2007)

=> i can use usb port for giving power to the device

now revision
i will take a receiver (TSOP1738 ) and put in front of my computer then i will join one of its pin to the +5(vcc) of the usb port and again connect that to the transmitter (BC547). Similarly to the gnd and data.
Are these correct then say ok.

And how do i know which point on that receiver and transmitter is for data transmission, gnd and vcc.


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## Kenshin (Sep 23, 2007)

tsop has 3 pins.....one to vcc of usb,one to gnd of usb.....3rd is Vout it will be connected thru a wire to the base of BC547 ...emitter of BC547 to gnd of usb....check the previous attachment for connections of vcc and gnd of bc547.


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## sourav (Sep 23, 2007)

i mean that to which point should connect which wres.

according to ur attachment

first pin is for vcc, gnd, data

and in transmitter
first is for vcc, data, gnd

is this correct


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## Kenshin (Sep 23, 2007)

see this now


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## sourav (Sep 23, 2007)

read it and reply

do i just need to show this to the electronic store and they can do it

and reply the question in the attachment


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## Kenshin (Sep 23, 2007)

see this


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## sourav (Sep 23, 2007)

atlast i understood but one more question

what is bc547??

and is it available easily, how much will these will cost and waht are the hassesls and will they occur in my use

is that resistor required which is of 4.7 ohm.


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## Kenshin (Sep 23, 2007)

BC547 -Transistor -  4Rs
IRLED                 -  5Rs
TSOP1738           - 15Rs
Resistor              - 1Rs


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## sourav (Sep 23, 2007)

other questions answer

did u mean 4.7k ohn or 4,7 ohm, as in the figure it looks 4.7 k ohm

help plz


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## Kenshin (Sep 23, 2007)

4.7 KiloOhms


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## sourav (Sep 24, 2007)

oye diagram is fully correct

i wanted to say that on the real resistor. how do i know which point is waht.

does the electrician would be knowing.

on more WHAT IS BC547?
is it used for converting digital signal to ir signals.


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## infra_red_dude (Sep 25, 2007)

a resistor doesn't haf any polarity. it doesn't matter to which end you connect. BC547 is a transistor. its used as a switch to activate the transmitter only when a button is pressed on the remote.


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## sashijoseph (Sep 27, 2007)

Well sorry for the bad news but the circuit would never work....
1)The IR LED is reverse biased.....swap the anode and cathode.

2)The 4.7k resistor wouldn't allow any(useful) current through the LED.
   Considering a working voltage of 1.5v for the LED and say 0.5v across BC547's CE,we have 5-(1.5+0.5)=3v across the resistor which would  provide for 3/4.7 = 0.64ma......a more usable resistor would be 56 or 68       ohms which would provide ~40-50ma.

3)There's no base resistor for the BC547 and the output pin of the TSOP is  internally pulled up so 5v would be applied to the base.So add a 4.7k resistor to limit the base current and potential transistor damage.

4)Where's the carrier?TheTSOP includes a demodulator so what you have   at it's output pin is the data *minus* the 38 khz carrier. Simply sending this data through the IR LED won't work because the Tatasky unit needs a 
  38Khz modulated signal from it's remote.So you'll have to modulate the data with a 38khz carrier.
  On second thoughts,the carrier filtered out by the TSOP should still be present albeit at a very low level.The BC547 would amplify this along with the data and hence it may work. You need to test though.

5)The transistor employed would invert the signal hence we need an  inverter before it so that the final output remains unaltered.You may use one part of a CD4049 hex inverter- buffer.

Whew that's about it.Look at the attachment for a modified ckt.Actually two....one using cd4049 inverter,the other using a transistor inverter.


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## Zeeshan Quireshi (Sep 27, 2007)

well u can get IR transmitter and Reciever Circuits *pre made* from electronic schops , so you'll just have to connect the output of IR reciever to input of ir transmitter n that should suffice u .

u'll get these curcuits at ur general electronic shop or else buy _electronics for you_ and order the Do It Yourself kits from the dealers listed there .


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## praka123 (Sep 28, 2007)

btw resistors are all quarter watt(.25?)?just want to quote the resistor color code mnemonic 
B.B. ROY of Great Britain had a Very Good Wife, Good Son

*en.wikipedia.org/wiki/Electronic_color_code


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## infra_red_dude (Sep 28, 2007)

yeah, for this circuit quarter watt resistors are sufficient.


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## Kenshin (Sep 28, 2007)

bout the modulator...i think it shud work...but IRs are unpredictable  
so a modulator with a 555 (astable at 38K)...output of which ANDed(7408 ) with the output of tsop..will do



			
				sashijoseph said:
			
		

> 3)There's no base resistor for the BC547 and the output pin of the TSOP is  internally pulled up so 5v would be applied to the base.So add a 4.7k resistor to limit the base current and potential transistor damage.



    Once i had a prob with tat 4.7K resistor....ckt din work only...later on removed it and voila....dunnu how...theoretically it shud be there....but practially it din worked for me..hehe...from then on i never use tat resistor...heck i dun use IRs also


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## infra_red_dude (Sep 29, 2007)

ppl.... why don't you use RF??? IR is too problematic, as said before!!


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## sourav (Sep 29, 2007)

cheap did u forgot that

rf costs 600 rs where this would cost less than 50 rs


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## Zeeshan Quireshi (Sep 29, 2007)

nah , it will cost atleast 100 bucks , considering hw much time and frustrated you're gonna be while soldering circuits or when something doesn't work(which is the case 99% of the time in electronics) .


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## Kenshin (Sep 29, 2007)

^^ +1


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## jj_alukkas (Sep 30, 2007)

Easy way... get an IR extender... 
If u hv experience in electronics, google for its circuit... I hv come across a lot of them...


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