Arduino - IR Repeater Tutorial (Part 2)

If you want to see the complete tutorial, please visit IR Repeater Tutorial Part 1 first.

Test out everything on the proton board:
It's always a good practice to test out the wiring before solder components together. 
Connect IR receiver LED to Arduino Pro Mini

Connect IR emitter LED through 100 Ohm resister

The program below was created by Lauszus that I found on Gighub. The original program was written to receive IR code and decode IR then save the IR code in the memory until a button is pressed to emit IR code. To meet my requirement, I made few modifications to make it receive IR, decode IR, and then emit the IR immediately. Here is my code:

[Programming code]

 * IRrecord: record and play back IR signals as a minimal 
 * An IR detector/demodulator must be connected to the input RECV_PIN.
 * An IR LED must be connected to the output PWM pin 3.
 * A button must be connected to the input BUTTON_PIN; this is the
 * send button.
 * A visible LED can be connected to STATUS_PIN to provide status.
 * The logic is:
 * If the button is pressed, send the IR code.
 * If an IR code is received, record it.
 * Version 0.11 September, 2009
 * Copyright 2009 Ken Shirriff
 * http://arcfn.com
 * Version 0.2 October, 2015
 * Modified to remove button function 
 * This module acts a IR Repeater to just 
 * "Read the IR Code " and "Send the IR Code" immediately
 * By En-Lin Chen / Stonez56

#include <IRremote.h>

int RECV_PIN = 2;
int STATUS_PIN = 13;

IRrecv irrecv(RECV_PIN);
IRsend irsend;

decode_results results;

void setup()
  irrecv.enableIRIn(); // Start the receiver

// Storage for the recorded code
int codeType = -1; // The type of code
unsigned long codeValue; // The code value if not raw
unsigned int rawCodes[RAWBUF]; // The durations if raw
int codeLen; // The length of the code
int toggle = 0; // The RC5/6 toggle state

// Stores the code for later playback
// Most of this code is just logging
void storeCode(decode_results *results) {
  codeType = results->decode_type;
  int count = results->rawlen;
  if (codeType == UNKNOWN) {
    Serial.println("Received unknown code, saving as raw");
    codeLen = results->rawlen - 1;
    // To store raw codes:
    // Drop first value (gap)
    // Convert from ticks to microseconds
    // Tweak marks shorter, and spaces longer to cancel out IR receiver distortion
    for (int i = 1; i <= codeLen; i++) {
      if (i % 2) {
        // Mark
        rawCodes[i - 1] = results->rawbuf[i]*USECPERTICK - MARK_EXCESS;
        Serial.print(" m");
      else {
        // Space
        rawCodes[i - 1] = results->rawbuf[i]*USECPERTICK + MARK_EXCESS;
        Serial.print(" s");
      Serial.print(rawCodes[i - 1], DEC);
  else {
    if (codeType == NEC) {
      Serial.print("Received NEC: ");
    else if (codeType == SONY) {
      Serial.print("Received SONY: ");
    else if (codeType == RC5) {
      Serial.print("Received RC5: ");
    else if (codeType == RC6) {
      Serial.print("Received RC6: ");
    else {
      Serial.print("Unexpected codeType ");
      Serial.print(codeType, DEC);
    Serial.println(results->value, HEX);
    codeValue = results->value;
    codeLen = results->bits;

void sendCode(int repeat) {
  if(codeValue == 0xFFFFFFFF) return;  //ignore FFFFFFF IR code
  if (codeType == NEC) {
      irsend.sendNEC(codeValue, codeLen);
      Serial.print("Sent NEC ");
      Serial.println(codeValue, HEX);
  else if (codeType == SONY) {
    irsend.sendSony(codeValue, codeLen);
    Serial.print("Sent Sony ");
    Serial.println(codeValue, HEX);
  else if (codeType == RC5 || codeType == RC6) {
    if (!repeat) {
      // Flip the toggle bit for a new button press
      toggle = 1 - toggle;
    // Put the toggle bit into the code to send
    codeValue = codeValue & ~(1 << (codeLen - 1));
    codeValue = codeValue | (toggle << (codeLen - 1));
    if (codeType == RC5) {
      Serial.print("Sent RC5 ");
      Serial.println(codeValue, HEX);
      irsend.sendRC5(codeValue, codeLen);
    else {
      irsend.sendRC6(codeValue, codeLen);
      Serial.print("Sent RC6 ");
      Serial.println(codeValue, HEX);
  else if (codeType == UNKNOWN /* i.e. raw */) {
    // Assume 38 KHz
    irsend.sendRaw(rawCodes, codeLen, 38);
    Serial.println("Sent raw");

void loop() {

  if (irrecv.decode(&results)) {
    /* Receive IR code */
    digitalWrite(STATUS_PIN, HIGH);
    irrecv.resume(); // resume receiver
    digitalWrite(STATUS_PIN, LOW);
    /* Send IR code */
    digitalWrite(STATUS_PIN, HIGH);
    digitalWrite(STATUS_PIN, LOW);
    delay(50); // Wait a bit between retransmissions
    irrecv.enableIRIn(); // Re-start the receiver

After programming code is copied into Arduino IDE, upload it to your Arduino Pro Mini.

Power it up and then use any remote control to point to IR receiver and observe the Arduino IDE Serial output screen.  Turn on Serial Monitor: Arduino -> Tools->Serial Monitor

Here shows you the IR command received through the serial port monitor.

Received NFC: FFA252D (Remote type is NEC, and the code is 0xFFA25D)
Sent NEC: FFA25D

After fully tested, it's time to solder everything together.
First, solder IR emitter LED to the extended long wires. Although not showing at the photo below, an 100 Omh resistor is needed on the data pin 2.

I soldered the IR receiver LED on small proton board to allow me to fix it into the IR BOX easier. 
To provide constant power, I decided to use a smart phone power adaptor through a USB connector.

There are 4 tiny wires in the USB cable and you only need black and red wire to supply power to Arduino Pro Mini.  Red connects to VCC and Black connects to Ground.

I've chosen to use a name card case as the enclosure. I drilled a tiny hole in the front of the name card case (see below), to expose IR receiver LED towards the edge.

Too often, accidentally pulling the wires will break the soldering part, so I tight a knot on the extended long wires to secure wires in place. 

Now, every parts are soldered together as you see below.

Emitter board and Arduino Pro Mini placement is looked like this below.

Then, I glue the entire board with a glue gun to secure PCBs inside the name card box.

Plug the USB adaptor to power it up. Great! It's working.

Below is how this project looked like. As you can see, the extended wires are almost five to seven meters long.

Follow IR Repeater Setup Illustration in Tutorial Part 1 
  1. Place IR BOX next to your TV and plug the USB adapter
  2. Pull the IR emitter with the wire through the wall into the living room
  3. Make sure the IR emitter is aiming towards the IR receiver on the Set Top Box
  4. I glue the IR emitter LED next to my couch and it working fine
  5. Done

After the setup, I've been use this IR repeater for 2~3 weeks and it's working perfectly without any issue. If you would like to make your own, you can follow this tutorial!

See the video below, if you haven't!




把所有電子零件都焊起來之前,我們最好利用洞洞板來測試一下,可以正常運作後才做焊接。請參考上圖,先用跳線把紅外線接收LED連線到  Arduino Pro Mini。

連接100歐姆電阻到紅外線發射 LED 正極

簡單的連線後,大致就完成了。接下來把下面的程式碼上傳到 Arduino 。


上方的程式碼的原作者是 Lauszus  (Github) ,此程式原本是要接受到紅外線解碼後,儲存在記憶體中,在使用者按下一個按鈕後才由紅外線發射 LED 發射出訊號。
為了符合這個 IR BOX 的需求,我做了一些修改,讓它收到後直接發射出紅外線編碼。
接上 5V 電源,利用 MOD 的搖控器對準 IR 接收LED。你可以在 Arduino IDE 的 Serial Monitor 上觀查 IR BOX 接收與傳出 IR Code 的資料。
打開 Serial Monitor 的方式: Arduino -> Tools->Serial Monitor 參考下圖:

Received NFC: FFA252D (Remote type is NEC, and the code is 0xFFA25D)
(IR 接收解碼為:FFA252D 搖控器類型 NEC)
(IR 發射碼)Sent NEC: FFA25D

先把 IR 發射 LED 焊到加長的電線上,別忘了在 LED 資料前焊上一個 100 歐姆的電阻(我底下的照片沒有這個電阻)。這個 IR 發射 LED 和兩條 7.5 公尺的電線就是要穿過牆放到到客廳裡。

我把 IR 接收 LED 焊在一塊洞洞板上,這樣可以讓 IR LED 固定的更好。
這個模組需要一個 5V 的電源長期供電才能運作,所以我找來一個手機的 5V 充電器來供電。

先把 USB 電源線剪一小段並剝去外面包覆的絕緣層。裡面有四條電線,我們只需要把紅色的焊接到 Arduino 正極(VCC),黑色的焊接到 Arduino 負極(GND),再把 USB 插到手機充電插頭即可以供電。

手上臨時找到了一個名片盒,就拿它來當做 IR BOX 的外殻吧!(好...我承認它不太美觀 ...Orz..)先在名片盒的側面鑽個小孔,只要讓 IR 接收 LED 可以外露出來,接受紅外訊號即可;如下圖:


再接著,把電源焊到Arduino Pro Mini,並把線路依圖示都焊上。

再把焊有紅外接收 LED 的洞洞皮放到名片盒裡試試看那個位置合適。

確定 IR LED 有露出到剛剛鑽孔的位置,再把Arduino Pro Mini 位置確定後,用很多的膠固定電路板的位置;如下:

接上 USB 電源後紅色 LED 亮起,表示 IR BOX 已正常的運作了,太好了!

我做的 IR BOX(紅外線轉發器)整個看起來就像下面一樣。IR BOX 連著長長的電線(7.5公尺),電線的尾端則是 IR 發射LED 。

依照教學的 Part 1 紅外線轉發器安裝方法圖示:
  1. 把 IR BOX 放在房間適當位置固定並插入電源
  2. 把長長的電源線和 IR 發射LED 穿過牆壁,
  3. 確認IR 發射LED 拉到能正對著機上盒的紅外接收位置 (Set Top Box)
  4. 我用膠槍把 IR LED 固定在沙發旁邊。
  5. 完成

安裝好後,我已經用了兩三個星期了,而且整個 IR 轉發器運作都很順利。
如果你也想要自己 DIY 一個話,可以自己開始動手了!!




Arduino - IR Repeater Tutorial (Part 1)

To share a Set Top Box in living room with Bedroom TV using the same Remote Control.

Recently, I subscribed a VOD (Video On Demand) service that came with a Set Top Box in the living room. However, I would like to occasionally watch VOD in the bedroom, but the Set Top Box is in the living room. As you know, there is no way to control the Set Top Box in the living room from the bedroom.  Yeah, an IR repeater is all I need. There are commercial products available in the market already, but I quickly thought about the Control celling light with a TV remote Arduino project I have done before might be an replacement for the IR repeater I need. After all, this is why I learn Arduino - May my life easier!!

Drawbacks of this project:
Either one VOD TV program can be watched from living or bedroom at a time, since the Set Top Box is shared. 

Arduino Programming Logic:
The programming logic to repeat the IR signal is quite simple
  • Receive remote control signal from IR receiver
  • Decode the IR code
  • Send the decoded IR code from the IR emitter

IR Repeater Setup Illustration:
The illustration below shows you how the whole IR Repeater is setup in my apartment to share Set Top Box in two rooms.
  1. Living Room TV
  2. Bedroom TV
  3. Set Top Box (HDMI out connect to a HDMI switch, yes you need this!)
  4. HDMI cable from Set Top Box to bedroom TV
  5. Arduino IR Box 
  6. IR Emitter
  7. A hole on the wall
* The IR remotes shown below are actually the same remote

Working IR Repeater Prototype Video:
See the working prototype in the video below. As you can see, even through the IR repeater, the Set Top Box response time is fairly quick!

Material Needed:
  1. Arduino Mini Pro
  2. IR Emitter 940nm * 1 
  3. IR Receiver LED, Aixin AX-1838HS 38KHz * 1 (Other brand 38KHz should work)
  4. ProtoBoard * 1
  5. 100 ohm resistor * 1
  6. Short Jump wires * 10 
  7. 5 meter long single wires * 2 

LED Lineup:
Starts from the left: IR LED receiver, IR LED emitter, green LED, and red LED.
In the end, I didn't use red and green and LED, but relied on the Arduino built-in red LED on pin 13 and Serial port green LED in this project.

IR Repeater Wiring:
Wiring up is quite easy as you can see below. (I forgot to draw the 100 Ohm resistor in the illustration below, but you need it.)
  1. IR Emitter GND to GND
  2. IR Emitter Data to 100 Ohm resistor to Arduino pin 3
  3. IR Receiver Data to Arduino pin 2
  4. IR Receiver GND to Arduino GND
  5. IR Receiver VCC to Arduino VCC
  6. Proton board GND to power source GND
  7. Proton board VCC to power source VCC (USB power adapter)

In part 2, I will show you how I made the IR Repeater box, schematic, and Arduino code I modified from github by Lauszus. If you are interested, you may take a look at the code first.

To be continued. 


不用另外租用一個額外的 MOD 機上盒,只要使用同一個搖控器,該你在臥室裡也可以觀看客廳所訂閱的中華電信 MOD! 

最近,我訂閱了中華電信MOD系統,我把機上盒放在客廳裡。但是,我偶爾想在臥室裡收看MOD。可是機上盒在客廳裡,要怎麼辦呢?大家都知道,我不可能從臥室裡控制位於客廳的MOD。是的,我只需要一個紅外線(轉發器, 這個名詞正確嗎?)。市面上的相關產品有一大堆,但是我很快的想起我以前做的 以電視遙控器控臥室天花板電燈開關。這就是為什麼我要學Arduino - 讓我生活的更方便!


Arduino 程式邏輯:

  • 用紅外線接收器接收遙控器的信號
  • 將紅外線信號解碼
  • 從紅外線發射器傳送出解過碼的IR信號

  1. 客廳電視
  2. 臥室電視
  3. 機上盒
  4. HDMI延長線要從臥室電視連到機上盒
  5. Arduino紅外線轉發器
  6. 紅外線發射器
  7. 牆上的鑽孔

請看以下的原型運作影片  可以看到即使經過轉接器 機上盒的反應仍舊相當迅速

  1. Arduino Mini Pro * 1
  2. 紅外線發射 LED 940nm * 1
  3. 紅外線接收 LED Aixin AX-1838HS 38KHz * 1 (只要是 38KHz 應該就能用)
  4. 麵包板 * 1
  5. 100歐姆電阻 * 1
  6. 短跳線*10
  7. 7.5 米長電線

各式 LED:
由左算起,IR 接收 LED, IR 發射 LED, 綠色 LED, 紅色 LED
這個專案裡,我最後沒有用到綠色 LED, 紅色 LED,我用的 Arduino 內建在13腳的紅色 LED, 和 Serial port 訊號的 LED.

接線很簡單,請參考下圖:(我忘了畫 100 Ohm 電阻,不過我們需要這個電阻)
  1. IR Emitter GND to GND
  2. IR Emitter Data to 100 Ohm resistor to Arduino pin 3
  3. IR Receiver Data to Arduino pin 2
  4. IR Receiver GND to Arduino GND
  5. IR Receiver VCC to Arduino VCC
  6. Proton board GND to power source GND
  7. Proton board VCC to power source VCC (USB power adapter)

在第二段教學裡,我會把我如何用手邊棄不用的東西來製作紅外線轉發器的外盒(不是很好看,但墈用),及分享我用的程式碼。如果你等不及,那你可以參考 Github by Lauszus. 我就是用這位前輩的程式碼來修改完成這個作品的。



Android control RGB LED using HC-05 Bluetooth module with Arduino (Part III) - Make A Night Lamp

It's been a while since I wrote the RGB LED tutorial on my blog. Not sure if you have done yours.

If you would like to learn the whole project from the scratch, please visit these two tutorial first.
- Tutorial 1
- Tutorial 2

Recently, I have found a night lamp laying around and we were not used it anymore. I thought, umm.. it might be a good idea to DIY RGB LED into this lamp. Let's get started!

This is what the lamp looks like below. It's powered up by a 9V/300mAh adapter. Since Arduino Mini Pro only take 5V or 3.3V, I had to replace a 5V/500mAh adapter from older 2G phones to use with this night lamp.
After I opened the light lamp, there was tiny PCB, few wires, and a very small lightbulb under the transparent cover. I removed most of stuff inside to make room for my Arduino board.

Since this is a night lamp, there is no need to let this lamp too bright. I decided to use 6 RGB LED to be the light source.  Please refer to my RGB LED tutorial 1 to see the how to wire up.
After soldered the LEDs, resistors, and wires, I cut down extra LED legs to ensure they could fit into the lamp.

There were only few things to solder on Arduino Mini Pro pins with RGB LED and signal wires.

HC-05 Bluetooth Module wiring as follow:

  • TX connect to Arduino Pin 11(RX)
  • RX connect to Arduino Pin 12(TX)
  • Remember to connect TX on the HC-05 to RX on the Arduino and RX on the HC-05 to TX on the Arduino, so Arduino can receive data correctly.
  • VCC connect to 5V power
  • GND connect to Ground
All parts were soldered together; including Arduino, wires, RGB LED.

Then, I attached HC-05 Bluetooh module on the the Arduino Mini Pro. 

** Remember to test it the whole thing to make sure it's working before you continue.**
I also cut the porto board in half to save more space below.

Look at the picture where I circled, I needed to keep the original connector to connect to Arduino Mini Pro, so the power plug can be inserted correctly into the lamp plug.

Here is the original PCB module come with the lamp. I just removed the connector with a plier instead of desoldering it.  Believe me, I did try to desolder the connector from the PCB and it was really difficult for me, even with a tiny tool that sucked the soldering away from PCB.

There is a battery compartment under this night lamp. So I decided to put HC-05 Bluetooth module into this compartment to save space.  By doing this, I had to insert 4 wires to go through the tiny hole in the center that was originally holding the light bulb. Since the thickness of the compartment door is quite thin, I could see the HC-05 Bluetooth LED indicator to see if it's connected or not! :)
** Fast flash: Not connected.
** Flash twice per 2 seconds: Connected.

After removed the light bulb, I was trying to find the perfect spot to place PCB and Arduino Mini Pro.  By the way...I almost forgot to solder the connector back to the power wires.

Now, it's time to put all components inside the lamp. I decided to use hot glue to place the PCB with RGB LED on the center and inserted Arduino Mini Pro next to the screw column.
Secure the connector with the original screws and a lot glue to keep them in place using a hot glue gun.
More hot glue to ensure the PCB and connector to fix and secure.

Power it up! Cool, it's working now! I modified Arduino programming a little bit to set my PCB to light up with Blue color as soon as it powered up.

Finally, I placed the cover back and tighten two screws and it's done!  This is my 2nd projects that really worked!

Now, I set next beside my children's bed to let him enjoy this magic night lamp and he loved it! :)

See the working video below:


Part III - Android HC-05 藍芽連線控制彩色 RGB LED: DIY 以手機控製夜燈

自從我把製作手機用藍芽搖控 RGB LED 彩色貼到部落格上,也有一段時間了。不知道你是否也依著步驟,DIY了你自己的呢?

- Arduino + BT + RGB LED 教學 1
- Arduino + BT + RGB LED 教學 2


我手上小夜燈看來如下圖,它是以一個 9V/300mA 變壓器來供電。不過Arduino Mini Pro 只能用 3.3V or 5V, 所以我找了一個早期2G手機用不到的5V/500mA 變壓器才取代。
打開小夜燈的上蓋,裡面的空間還算多,只有一片小小PCB, 幾條線和一個小燈泡。

反正是個小夜燈,用不著太亮,所以我只用了6個RGB LED並聯在一起。
連接方法請參考 RGB LED 教學 1
把 LED, 電阻, 電線焊好後,再把過長的 LED 腳剪斷就行了。

為了方便參考, 這裡是連接的方法,唯一不同的是把 6 個 RGB LED 並聯就行了。

HC-05 Bluetooth Module wiring as follow:

  • TX connect to Arduino Pin 11(RX)
  • RX connect to Arduino Pin 12(TX)
  • Remember to connect TX on the HC-05 to RX on the Arduino and RX on the HC-05 to TX on the Arduino, so Arduino can receive data correctly.
  • VCC connect to 5V power
  • GND connect to Ground
接著把線路和 Arduino Mini Pro 焊上。

接下來,把 HC-05 籃芽模組也一起焊上。

** 別忘了先試試整個電路板都運作正常 **

底下圈起來的是原先小夜燈用的連結座,我要把這個連結座拆下來,這樣搭配 5V/500mA的變壓器使用剛剛好。


小夜燈底下有個裝電池的空間(如下圖)。我把藍芽模組 HC-05 經由裝燈泡的洞穿過去,這樣可以節省一些空間。電池座的塑膠門剛好又非常的薄,所以可以這裡看到 HC-05 藍芽連接的燈號。
** 快速閃爍: Not connected.
** 每兩秒閃二之: Connected.

PCB, Arduino 放置的方式如下圖,PCB放在中間,而 Arduino Mini Pro 放在螺絲座的旁邊。

用更多的熱熔膠把 PCB+LED 固定在夜燈正中間。

插上電源試試! 把前面的教學程式稍作修改,該每次接上電源後,讓它點亮藍色的。

最後,把外蓋蓋回去,鎖上螺絲就完成了!這是我做 Arduino 以來的第二個作品可以用在生活中!