This project came about due to my folks cable company switching over to all digital. Like most folks they had been replacing their TVs with digital ready LCDs over the years so did not figure this would be a major issue. BUT... the cabled company's digital system will ONLY work with their cable box and they charge a rental fee per month per box with no option to buy your own. Currently my folks have 5 TVs but only ever watches 2 of them at any one time. Instead of renting 5 boxes they wanted to just be able to use just 2 boxes on multiple TVs. The splitting of the output signal is easily accomplished with standard cable TV splinters. But needed a way to control the cable box from the various remote locations.

Since there are tvs in multiple rooms they needed a multiple input and single output IR system. Looking around I found multiple systems that had a single input and multiple outputs for use in cabinets but not much for multiple inputs that was for a reasonable price. In the end I decided to just make my own system. I installed 3 IR-RX driving a IR-TX to one cable box and 2 IR-RX driving a second IR-TX on the second box. Both cable boxes were mounted in the basement near the cable lines and all the IR-RX and IR-TX were wired up with standard 4 conductor phone wire. So far ~6 months in no issues with the system. Folks picked up some cheap universal remotes and programmed to the cable boxes and left them in each room.

The design is as universal as I could make it. There are multiple ways it can be used some examples are:

1.) Single in single out. This is the setup is normally used for taking a signal from outside a cabinet to the inside.

2.) Single in multiple out.

3.) Multiple in single out. I used this setup for my folks.

4.) Multiple in multiple out.

5.) Remote IR receiver for a micro controller.

6.) IR transmitter for a micro controller.

7.) IR trip wire.

Step 1: Bill of Materials

Depending on what your end use is you will need a varying number of IR-TX and IR-RX kits. For the basic use case you will need 1 IR-TX, 1 IR-RX, hookup wire, and a power supply.

For the hook up wire just about any low voltage hookup wire will work. I used 4 conductor telephone wire since it was cheap and easy to obtain at any home improvement store. At a minimum you need 2 wires (ground and signal) between all the IR-TX and IR-RX on the circuit. With only 2 wires each IR-TX and IR-RX will need it's own power supply. 3 conductors or more is the best option as it allows for power to be transmitted along with the signal so only one power supply is needed.

For the power supply a old wall wart from a USB hub was used. Any power supply with a output of 7.5Vdc to 12Vdc at 1A or greater is sufficient to run multiple IR-RX and/or IR-TX. I have personally tested 2 IR-RX and 3 IR-TX on a single 7.5Vdc @ 1A wall wart with no issue.

The bill of material for the IR-TX is:

1x 940nm IR led
1x 8 dip socket
1x 10uF 35V elec capacitor
1x 1uF 50V capacitor
1x 0.1uF 50V capacitor
1x 2N7000 N fet TO-92 package
1x 5mm green led
1x 43 ohm resistor 1/4W
1x 200 ohm resistor 1/4W
1x 1k ohm resistor 1/4W
1x screw terminals 5mm pitch 3 position
1x micro controller PIC12F1572 programmed with IR-TX firmware
1x LM78L05 5V reg TO-92 package
1x PCB

The bill of material for the IR-RX is:

1x 38kHz IR receiver module
1x 10uF 35V elec capacitor
1x 1uF 50V capacitor
2x 2N7000 N fet TO-92 package
1x 5mm green led
1x 200 ohm resistor 1/4W
1x 10k ohm resistor 1/4W
1x screw terminals 5mm pitch 3 position
1x LM78L05 5V reg TO-92 package
1x PCB

IR-TX and IR-RX kits are available here:

IR-TX: https://www.tindie.com/products/tymkrs/ir-transmitter-kit/

IR-RX: https://www.tindie.com/products/tymkrs/ir-receiver-kit/

The PCB gerber data and micro firmware can be found on my website here: http://www.wire2wire.org/IR_repeater/IR_repeater.html

Also needed is a 9V battery and a battery snap or alligator test clips for testing only.

Step 2: IR-RX Circuit Description

The signal starts off coming in U1 as IR. U1 does most of the heavy lifting of the circuit by converting the modulated IR signal to a demodulated TTL active low signal. The decoder included in the kit is for a 38kHz carrier frequency. They are available in multiple frequency options from 30kHz to 56kHz. From my testing around home I have not found any remotes that did not work with the 38kHz module.

R1 is optional in case the IR receiver module chosen has a open collector output. The module included in the kit does not require R1 to be installed.

Q1 and R2 form a inverter to invert the active low output to a active high.

D1 and R3 are the output indicator. With the Q1 inverter the LED is set up to be on when the signal is not present and off when present.

Q2 is set up as another inverter and open collector driver. This results in the final output of the circuit as a open collector active low output.

The remaining parts are a CN1 the output connector and C1, C2, and U2 form the 5V regulator.

Step 3: IR-TX Circuit Description

In the case of the IR-TX circuit the open collector signal comes in the connector CN1 and is pulled up by R1.

U2 is a PIC12F1572 micro controller and needs to be programmed before installing in the circuit. In this case it has a few different functions. The main function of the micro is taking the TTL input and encoding it on the 38kHz carrier wave. It also redrives the input signal out to the status indicator.

P1, P2, and P3 are optional jumpers to set the carrier frequency. As of the writing of this instuctable only the following settings are defined.

P1	P2	P3	Carrier frequency
open	open	open	38kHz
short	open	open	36kHz

D1 and R2 make up the status indicator. The indicator is set up so it is on when there is no input signal and blinks off when there is a signal present.

Q1, D2, and R3 make up the output stage. Q1 acts as a power booster to drive the IR led at 100mA.

U1, C1, C2, and C3 make up the 5V regulator circuit.

Step 4: IR_RX Assembly Start

Pull out the IR-RX PCB as shown above. The upper card in the photo is the top component side of the card. The lower image is the bottom solder side.

Step 5: IR-RX Install the Resistors

First locate R2 a 10k Ohm resistor (color code brown black orange gold).

Fold over one of the leads so the resistor makes a skinny U.
Install the resistor in location R2. Electrical polarity of the resistor does not matter. But, line up the body of the resistor with the pad with the white circle around it for mechanical clearance.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Find R3 a 200 Ohm resistor (color code red black brown gold) and repeat the above operations.

Step 6: IR-RX Install the Connector

Locate the 3 pin terminal strip.

Insert the terminal strip in location CN1 making sure the open end face away from the rest of the components. (See photo above)
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 7: IR-RX Capacitor Install

First locate C1 the 1uF electrolytic capacitor (can shape with radial leads)

First locate the negative side of the capacitor. This is normally marked on the body of the cap as a stripe with "-" signs and / or the shorter of the two pins.
Install the capacitor taking care to line up the negative side of the cap with the round pad with the "-" mark on the silk screen.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Repeat the above process with C2 the 10uF electrolytic capacitor (can shape with radial leads)

Step 8: IR-RX Power Regulator

Note this step and all future steps the components and the assembly are ESD sensitive! Make sure to use safe ESD handling procedures.

There are 2 options for the regulator install. Pick the option below that applies to your use case.

Option 1 = 7.5V to 12V powered. (Most applications using a AC to DC wall wart power supply)

Locate U2 the LM78L05 5V regulator.

Line up the body of the LM78L05 package with the outline on the silkscreen. Make sure the flat side of the package faces the flat side on the silk screen.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Option 2 = 5V powered. (For regulated 5V power supplies only.)

Set aside the LM78L05 regulator as it will not be used. Instead use a small chunk of wire to jumper pin 1 to pin 3 (outer pins) of location U2 on the PCB. This bypasses the regulator and feeds the 5V at the screw terminals directly into the 5V rail on the PCB.

Step 9: IR-RX Fet Installation

Locate Q1 the 2N7000 N-FET.

Line up the body of the 2N7000 package with the outline on the silkscreen.
Make sure the flat side of the package faces the flat side on the silk screen.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Repeat the above steps for Q2 another 2N7000 N-FET.

Step 10: IR-RX LED Installation

Locate the green LED.

Before you install the LED decide if you want to mount it facing strait up or at a right angle to the PCB. If mounting at a right angle make sure to bend the leads over before before installing it. Photo shows the LED built installed at a right angle.

Locate the negative side of the led. It is on the side of the body with the flat and/or the shorter of the two leads.
Install the LED in location D1 make sure to line up the negative side of the led with the flat side of the silkscreen (side closest to U1).
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 11: IR-RX Install the IR Receiver

Locate the IR receiver IC.

First set the sensor down on a flat surface with the dome side up. The dome is the IR sensor lens and must face out towards the IR remote. With the legs towards you pin 1 is on the left and pin 3 is on the right.

First decide which way you want the IR receiver to face. If you want it to face out at a right angle to the board install as is. If you want it to face out perpendicular to the board bend the leads at a right angle at the base of the part. Make sure the domed side of the part faces out.

Line up pin 1 with the square pad at location U1.
Install the sensor slightly raised off the PCB.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 12: IR-RX Build Verification

Verify the locations, orientation, and solder joint quality of all the parts. Use the 2 above images as reference.

Step 13: IR-RX Testing

For this step you will need a 9V battery (not included) and either a battery snap or jumper clips (also not included).

Connect the negative side (- or typically the black wire) of the battery to the "GND" screw terminal.

Connect the positive side (+ or typically the red wire) of the battery to the "V+" screw terminal.

If the green LED does not come on or any part of the circuit starts to get hot disconnect the battery immediately!

If the green LED comes on and there is no heat or smoke grab a standard IR remote control (not included) and point it at the IR receiver module (U1) dome side. Press buttons on the remote (exact one unimportant) and watch the green LED. If the LED flickers or blinks when the buttons are pressed the circuit is working properly.

If either of the above checks fail go back and review the solder joints and placement of components. Normally find solder opens/shorts or backwards parts on non functional kits.

Step 14: IR_TX Assembly Start

Pull out the IR-TX raw card as shown above. The upper card in the photo is the top component side of the card. The lower image is the bottom solder side.

Step 15: IR-TX Install the Resistors

Note resistor R1 should be omitted in some special configurations. If using multiple IR-TX modules on the same sensor chain only install R1 on ONE of the modules.

First locate R1 a 1k Ohm resistor (color code brown black red gold).

Fold over one of the leads so the resistor makes a skinny U.
Install the resistor in location R2. Electrical polarity of the resistor does not matter. But, line up the body of the resistor with the pad with the white circle around it for mechanical clearance.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Find R2 a 200 Ohm resistor (color code red black brown gold) and repeat the above operations.

Find R3 a 43 Ohm resistor (color code yellow orange black gold) and repeat the above operations.

Step 16: IR-TX Install the Connector

Locate the 3 pin terminal strip.

Insert the terminal strip in location CN1 making sure the open end face away from the rest of the components. (See photo above)
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 17: IR-TX Capacitor Install

First locate C1 the 1uF electrolytic capacitor (can shape with radial leads)

First locate the negative side of the capacitor. This is normally marked on the body of the cap as a stripe with "-" signs and / or the shorter of the two pins.
Install the capacitor taking care to line up the negative side of the cap with the round pad with the "-" mark on the silk screen.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Repeat the above process with C2 the 10uF electrolytic capacitor (can shape with radial leads)

Next locate C3 the 0.1uF ceramic capacitor (disk shaped with radial leads)

Install the capacitor in the PCB in either orientation as the ceramic capacitor is not polarized.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 18: IR-TX 8 Pin Socket

Find the 8 pin dip socket in the kit.

Note one end of the socket has a small notch in it. Line this notch up with the marking on the silk screen for U2. (it's the end nearest to the edge of the board away from U1.)
Install the socket in the board making sure all the pins stick though.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 19: IR-TX Install Jumpers [OPTIONAL]

If needed install jumpers at locations P1, P2, and P3 as needed to set the output carrier frequency.

See the circuit descriptions for more information. Most applications can use the default value of 38kHz which is no jumpers installed.

Step 20: IR-TX Power Regulator

Note this step and all future steps the components and the assembly are ESD sensitive! Make sure to use safe ESD handling procedures.

There are 2 options for the regulator install. Pick the option below that applies to your use case.

Option 1 = 7.5V to 12V powered. (Most applications using a AC to DC wall wart power supply)

Locate U1 the LM78L05 5V regulator.

Line up the body of the LM78L05 package with the outline on the silkscreen. Make sure the flat side of the package faces the flat side on the silk screen.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Option 2 = 5V powered. (For regulated 5V power supplies only.)

Set aside the LM78L05 regulator as it will not be used.

Instead use a small chunk of wire to jumper pin 1 to pin 3 (outer pins) of location U1 on the PCB. This bypasses the regulator and feeds the 5V at the screw terminals directly into the 5V rail on the PCB.

Step 21: IR-TX Fet Installation

Locate Q1 the 2N7000 N-FET.

Line up the body of the 2N7000 package with the outline on the silkscreen.Make sure the flat side of the package faces the flat side on the silk screen.
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Step 22: IR-TX LED Installation

Locate the green LED for location D1.

Locate the negative side of the led it is on the side with the flat on the body of the led and/or the shorter lead.
Install the LED in location D1 make sure to line up the negative side of the led with the flat side of the silkscreen (side closest to U1).
Flip the card over and solder the leads to the PCB.
Verify the solder joints are good and there are no shorts between the pads.
Trim the wire leads off flush with the top of the solder fillet and flip the card back over.

Repeat the above steps for the IR led (clear package) for location D2

Step 23: IR-TX Install the Microcontroller

Locate the PIC12F1572 micro controller. If not using a kit make sure to program the micro before use! Unprogrammed chips will not function in this circuit.

First gently bend the legs of the micro controller slightly inwards so they line up properly with the socket. Align the notch on the micro controller with the notch on the dip socket at location U1. Line up all the pins and firmly press the micro into the socket.

Verify all 8 pins went into the socket holes and did not get bent over / under the chip or went outside of the socket body.

Also at this time review all the component placement and solder joints. Fix any miss placed components, cold solder joints, and solder bridges before continuing.

Step 24: IR-TX Testing

For this step you will need a 9V battery (not included) and either a battery snap or jumper clips (also not included).

Connect the negative side (- or typically the black wire) of the battery to the "GND" screw terminal.

Connect the positive side (+ or typically the red wire) of the battery to the "V+" screw terminal.

If the green LED does not come on or any part of the circuit starts to get hot disconnect the battery immediately!

If the green LED comes on and there is no heat or smoke continue to the next step.

If the above checks fail go back and review the solder joints and placement of components. Normally find solder opens/shorts or backwards parts on non functional kits.

Step 25: System Testing

The final test step is to try running a IR-TX from a IR-RX.

First make the following connections:

IR-TX "V+" to IR-RX "V+" to battery "+" (typically the red wire)
IR-TX "SIG" to IR-RX "SIG"
IR-TX "GND" to IR-RX "GND" to battery "-" (typically the black wire)

Next connect the battery and verify both green LEDs turn on. If not disconnect the battery immediately and double check the wiring.

If the LEDs turn on and there is no heat or smoke grab a standard IR remote control (not included) and point it at the IR receiver module (U1) dome side. Press buttons on the remote (exact one unimportant) and watch the green LEDs. If both LEDs flickers or blink in sync when the buttons are pressed the circuit is working properly.

Here is a quick video on how it should be hooked up and what to look for.

If either of the above checks fail go back and review the solder joints and placement of components. Normally find solder opens/shorts or backwards parts on non functional kits.

At this point all parts of the kits has been tested with the exception of the following parts Q1, D2, and R3. If once installed the green leds work as expected but the device your trying to control does not respond check these parts first.

Step 26: Installation Notes

First off verify the output polarity and voltage of the power supply. Make sure it is either between 7.5V and 12V or 5V depending on which power option you chose.

For wire standard 4 wire telephone cable is cheap and suitable. For my folks installation I used red for +7.5V, black for ground, Yellow for signal, and left the green wire unconnected.

See the attached pictured for sample wiring diagrams.

1.) Single in single out. This is the setup is normally used for taking a signal from outside a cabinet to the inside.

2.) Single in multiple out. Make sure to remove R1 from all the IR-TX but one.

3.) Multiple in single out. I used this setup for my folks.

4.) Multiple in multiple out. Make sure to remove R1 from all the IR-TX but one.

5.) Remote IR receiver for a micro controller. This is not all that useful since you can attach the sensor directly to the micro. But would be useful if you want the IR receiver far away from the micro. You need to just add a 1k Ohm pull up to the input signal to the micro.

6.) IR transmitter for a micro controller. This is more useful as you can offload the signal encoding to the IR-TX. Just need to provide the TTL input of the signal you want to encode.

7.) IR trip wire. This one requires some mechanical modifications. You would need to add a IR Opaque tube to both the transmitter and receiver. This is to improve the directionality of the beam. A ball point pen tube works well. After that just wire the input of the IR-TX low to have it send out a constant stream of IR. On the IR-RX side wire up the output to the input of the micro controller with a 1k pull up resistor. When the output is high the beam is broken. When the output is low the IR beam is made.