In this post we will learn how to increase or extend the range of an ordinary infra red or IR remote control through a 433MHz RF remote control system.
IR Range Extender Concept
The idea of this circuit is to feed the IR data from an IR transmitter into the transmitter input of an RF module through an IR sensor, and transmit the data in air so that the distant RF receiver module is able to receive the data.
After receiving the data the RX would decode it and convert it back to IR based data, which could be used for triggering the relevant IR operated distant device.
Parts You will Need to Build this Circuit
Transmitter Stage
433MHz or 315 MHz RF Encoder Modules, as shown in the following article, and assemble them as show:
How to wire RF Module circuits
All below shown Resistors are 1/4 wat t 5% CFR, unless otherwise specified
1M - 1no, 1 K - 4nos, 100ohms = 2nos,
Transistor BC557 = 1no
Capacitor 10uF/25V = 1no
Receiver Stage
433MHz or 315 MHz RF Decoder Modules, as shown in the above linked article, and to be assembled as show:
1K = 1no, 10K = 1no, 330ohms = 2nos, 33K = 1no
IR photodiode (any type) = 1no
Transistor = BC557
RED LED = 2nos
Capacitor -= 0.01uF
The IR to RF Range Extender Transmitter Circuit
The figure above shows the basic layout for the infrared remote control range extender transmitter circuit, wherein a 433MHz or a 315MHz RF encoder circuit can be seen built around the chips HT12E and TSW434, and we can also see an attached simple IR sensor circuit stage using TSOP730.
The IR sensor can be visualized at the extreme right side of the diagram with pinouts: Vs, Gnd, and O/p. The output pin is connected with the base of an PNP transistor, whose collector is integrated with one of the 4 input pinouts of the RF encoder IC HT12E.
Now, to enable transmitting of the IR data to a distant location to extend its range, the user has to point the IR rays on the sensor from a IR handset and press the relevant button of the IR handset remote.
As soon as the IR rays hit the TSOP sensor, it converts the data into its respective PWM format and feeds the same to the selected input pinouts of the HT12E encoder.
The encoder IC picks up the converter IR signals, encodes the data and forwards it to the adjoining TSW434 transmitter chip for allowing the transmission of the data into the air.
The signals travels through air until it finds the antenna of the corresponding RF decoder module using 433MHz or 315MHz as the operating frequency.
The Range Extender RF Decoder Receiver Circuit
The circuit diagram shown above represents the IR data receiver circuit which receives the transmitted signal from the transmitter end and reverts the signals back to the IR mode for operating the IR device extended at this remote end.
Here the RF decoder module is built using HT12D IC and the receiver using RSW434 chip. The receiver chip picks up the transmitted IR to RF converted data, and sends it to the decoder IC, which completes the process by decoding the RF signals back to IR frequency.
This IR frequency is appropriately fed to an IR photo-diode driver circuit built using a PNP transistor and an IR photo-diode device, as shown at the extreme right side of the circuit.
The decoded RF to IR frequency is oscillated and transmitted by the photo-diode and applied on the device which is to be operated at the remote end.
The device hopefully responds to these RF decoded IR signals and functions as per the expected specification.
This concludes the IR range extender circuit using RF 433MHz modules, if you think I have missed something in the design or in the explanation please feel free to point them out through the comment box below.
Vaisakhan says
Swag,
I made this circuits but have some isdues; the txmr seems working good but the rxvr end led connected on pin10 is on & will off once the txmr switch on & the led connected pin 17 will on. It will blink according to the ir signal receiving in txmr. Also the ir led is not giving any ir out. Your advice will highly appreciate & thanks in advance.
Swag says
Hi Vaisakhan,
If pin#10 is blinking it means the IC is responding to the input signal from the transmitter, in that case pin#10 LED should also blink accordingly? Nevertheless, I’ll try to modify receiver transistor section with another PNP, and then you can test it again, hopefully it should work. I’ll do it soon.
Vaisakhan says
Many thanks..for your regular support
Vaisakhan says
Also..led in pin no 10 goes off & led in pin 17 on & it is blinking as per remote signal receiving in txmr end
Swag says
Something seems to be not right. You can do this, disconnect the emitter of the PNP in the transmitter circuit, and tap the pin#10 line of the Tx IC with the ground line, and check whether this correspondingly flashes the LED at pin#10 of the Rx circuit or not? This will prove whether the Tx and Rx are correctly synced or not
Vaisakhan says
Yes. Disconnected the emitter of pnp and grounded pin #10 & the rxvr end pin #10 led flashing.
Swag says
Vaisakhan, If manual pulsing is operating the pin#10 LED then the same should happen from the pulses generated by the TSOP? I’ll do one thing I’ll add one more transistor and LED to the Tx sensor stage, that will make things absolutely clear, I’ll update it soon.
Swag says
I have modified the Tx diagram by adding an extra BC547 and an LED, please upgrade your circuit with these mods and check the response
Vaisakhan says
Added BC547& led in txmr. This LED flashing as per ir signal from remote. Still at rxvr end led in pin#10 goes off when txmr switch on.
Swag says
that is very strange, if the red LED of the Tx is flashing then the pin#10 should also switch at the same rate. Just disconnect the BC557 base from the TSOP and check what happens, it is actually a just a matter of seconds to rectify the issue but since I am not able to see the set up practically therefore it is taking so much time.
Vaisakhan says
Base of 557 disconnected from tsop base & it is not receiving ir signal from remote. Instead of pin #10 can I use any pin # 11 ,12 or 13 in txmr & rxvr respectively?
Swag says
OK that means the transistor stage is not faulty and is not causing any leakages.
Yes definitely you can try other output also, but make sure to change the Tx inputs also accordingly to match the corresponding Rx output.
Alternatively since you are seeing D5 at pin#17 of Rx vibrating in accordance with the input remote frequency, in that case you can also try replacing D5 with an IR LED and check the response.
Vaisakhan says
Tried other pins but no success. D5 replaced with IR led & it is flashing as per remote signal but not switching on any remote controlled devices.
Just a humble query. Is it possible to replace transistor section by any ICs like CD4093?
Thanks a lot for your patience & valuable time.
Swag says
Transistor stage will be required in the TX section, you can include 4093 gates in between the collector of BC547 and pin#10 of Tx IC
Short all the input pins of the 4093 gates, then join all the 4 gates in series, meaning join output of one gate with the shorted input of the next gate.
In this way finally you will have one input and one output from the 4 series gates, connect the input with the collector of BC547, and the output with pin#10
Swag says
for the Rx you can do the same, and here you can remove the transistors, and use only IC 4093 gates
Swag says
I have updated the modified diagram, please do it as indicated in the diagram and let me know….
Vaisakhan says
Added the diodes & transistor but still no IR out from Rxvr end. Led in pin 17 still blinking as per IR signal receiving in txmr but the led in pin no 10 goes off when txmr switch on. Awaiting for your reply.
Aristarcus says
Dear sir, my best respects to you. I want to know how range of this transmitter. Thanks.
Aristarcus.
Swag says
Aristarcus, the range will depend on how far the IR wave is able to travel and reach the receiver sensor…and these two Tx and Rx will need to be exactly in line for the system to work…
Norman says
Hi Swagatam,
Can IR be used outdoors. I have tried and the sun makes the receiver think it is receiving the IR signal. I tried putting the receiving photo diode in a black tube but the sunlight penetrates and causes false signals. Maybe I should be using TSOP 1738. I just tried a regular photo diode and also a photo transistor. I was trying to place the receiver in my postal box so when the door was opened, the sunlight would trigger and I would send a signal to a receiver inside my house by way of RF TX/RX. The postal box is metal. Would this prevent the TX from being able to send the signal out? If so, maybe I should house my TX outside of the postal box which would make using an external antenna a better option. Also, what is the best antenna for 433mhz TX/RX? I have tried several without very good results. In a separate post I have requested your help. Thanks, and I hope this will make interesting reading for your Blog.
Swag says
Hi Norman, sunlight may be including many complex IR frequencies, so even a TSOP1738 could get rattled on some occasions, best option is to use an RF 433MHz based system for the operations. Yes whether RF or IR, a metal box will prevent the signals from radiating correctly. However if you hang the antenna of the RF Tx module out of the metal box, that may do the trick, just make sure the metal box body is not grounded.
A flexible wire around 2 meter long works best as an antenna for these RF modules, as per my experience.
Norman says
Thanks! I really appreciate your quick response.
Swag says
you are welcome!
N.Kesav says
Hai sir,,,,,
If it possible to send audio signal in RF…
Swag says
yes it may be possible by first converting the audio into pwm through a class D amplifier, and then receiving the output again through a class D amplifier
N.Kesav says
Sir pls give me the circuit
N.Kesav says
How to convert the signal sir…
The o/p of audio need to connect in data pin transmitter module..
And receiver module data out to input amplifier…
Sir if u have circuit pls provide me sir
Swag says
Hi Kesav, I’ll present the design soon, as soon as I get time…
Vaisakhan says
Thanks for publishing much awaited circuit. Please confirm whether can use TSOP 1738 in IR sensor
Swag says
Glad you liked it, yes the sensor is a TSOP as required by you…..