Thinking: How to make Ambilight clone for Raspberry ?

Very long title… but worth reading if you plan to make ambilight clone for your LED TV. After a few days of "hard work" I will try to make complete guide what RGB diodes and software to choose and how to solve all traps while trying to make Ambilight for you LED TV!

Idea

Idea is to add LED RGB strip behind your LED TV that will change colours according to video that your player (Raspberry Pi) is playing. Why? Because you can :) and it is easier for your eyes at night.

Software for Ambilight Arduino Raspberry clone

Raspberry Pi OS

First there is some "fresh" information. XBMC is now called Kodi. Basically it is part of the software responsible for multimedia playing. If you have stand alone PC hardware you can install it additionally to you operating system. But if we are talking about Raspberry Pi, most reasonable is to choose distribution (SD card image) that comes with preinstalled XBMC. Now there are several options:

• Raspbmc available here: http://www.raspbmc.com/index.html In last month it was announced that project is closing down, but it is stable, all plugins work so still it is valid option
• OSMC (Open Source Media Center) is new OS that inherits Raspbmc. It is available here: https://osmc.tv It boots very fast and has fresh look. Alpha version that we tested are not yet stable (that's why they call them alpha) but it looks very promising. Bad news that there is no support for Boblight, and good news that they will support Hyperion. So you can check their progress.
• OpenElec – RECOMMENDED – you can get image for your SD card here: http://openelec.tv/get-openelec It is very stable, supports Boblight and it is possible to add Hyperion too. Only drawback – you can not change root password easily (?!)

Software for LED backlight

Basically we have two major options: Boblight or Hyperion They have slightly different approaches, while Boblight consisting of daemon – server (boblightd) and XBMC boblight plugin as client. Plugin is responsible for all calculations (grabs edge pixels of screen) and serialises all data to boblight daemon that then sends all data to your Arduino "driver". This has big drawback – impact on your CPU and mayor issue – lag, and we want RGB lights running lightning fast!

Boblight XBMC client + Boblightd daemon

Nevertheless Boblight could be viable solution for some systems, and I have found very good guide and info about boblight setup here (Thanks Hans!): http://www.tweaking4all.com/home-theatre/xbmc/xbmc-boblight-openelec-ws2811-ws2812/ Hans also made fantastic utility for making boblight configuration files : http://www.tweaking4all.com/home-theatre/xbmc/boblight-config-maker/ Be sure to check it even if you are going Hyperion way, because his utility can help you calculate initial prefix bytes, but more on that in Arduino section.

Why choose Hyperion?

For start it is newer and more promising. But here are some real advantages:

• It is very fast (almost no delay compared to almost 1sec lag with boblight)
• Priority channels – while you are watching video you can use mobile app to override colors or play effect!
• Did I mention mobile app for iOS ?

Check up-to-date wiki here: https://github.com/tvdzwan/hyperion/wiki

How to install Hyperion?

Login to your SSH on OpenElec (You must enable it first in system settings services. Username "root" password "openelec") and type:

curl -L --output install_hyperion.sh --get https://raw.githubusercontent.com/tvdzwan/hyperion/master/bin/install_hyperion.sh

sh ./install_hyperion.sh

Detailed installation guide available here

Hyperion JSON configuration

You can be guru and write your own config file, or just get and use latest Hyperion JSON configurator utility here or
grab jar

What about LED placement?

Here is sketch of my LED placement. Keep in mind in what direction are you putting LED strip, count number of leds from each side, top, bottom, and gap if you have it.

How to make config file?

Config file for Hyperion is .JSON file. They made a  nice java utility, so use it to generate first config file, upload it to your Raspberry (using SCP) or just copy paste it to shell and than make some fine tuning in shell editor like "nano". Detailed information here   

How to change  Hyperion configuration or troubleshoot?

If setup is not working, first check if the hyperion is running by typing:

ps -a | grep hyper

It it shows process and it is stalled you can kill it and stat Hyperion again with:

killall hyperiond /storage/hyperion/bin/hyperiond.sh /storage/.config/hyperion.config.json </dev/null >/dev/null 2>&1 &

If you want to see and debug hyperion messages run it instead with (omiting suffix of previous command):

/storage/hyperion/bin/hyperiond.sh /storage/.config/hyperion.config.json

There is an easy way to test it using one of shell commands below (for solid colour or Rainbow effect):

/storage/hyperion/bin/hyperion-remote.sh --priority 50 --color red --duration 5000 

/storage/hyperion/bin/hyperion-remote.sh --effect "Rainbow swirl fast" --duration 3000

If it still does not work you can always edit configuration, adjust it,

nano /storage/.config/hyperion.config.json

Remember that hyperion must reload configuration so kill hyperion and start it again as explained above

Hardware for "RGB delight"

What RGB diodes to choose?

There are many options for RGB LED strip. Idea is to have controlable one – to be more specific RGB diodes that you can individually control. So be careful while you are ordering your 5m pack. What model should you choose? I was thinking about WS2801, WS 2811, WS2812, WS2812b. Keeping it short, you should go for WS2812b IP65.

Why choose WS2812b with IP65 and 3M stick tape, 60 leds/m?

Advantages:

• They use just 3 wires! +5v, GND and DATA line.
• WS2812 have chip integrated in 5050 RGB diode!
• WS2812b have reverse voltage protection (it is easy to mix two wires and kill LED strip if you do not have b version)
• IP65 gives you silicone over diodes, I like that more than IP67 (plastic tube). It is good that your LED strip is protected from dust etc.
• 3M stick tape helps you to stick the diodes direct to TV (if you are less brave and would like to make frame, check some websites)
• they come in 3 variants 30LED, 60LED or 144LED / m. I think that 60LED/m provide optimal brightness.

WS2812 main drawbacks:

• Hard to controll It can not (or can but it is not easy to do) be controlled directly from Raspberry Pi2! You must use Arduino. Why? Because it needs 800kHz signal and your Raspberry Pi is not running realtime OS, so any interrupt will brake the timing and cause problems and unreliable behaviour
• Expensive You can expect price per m about $12. (March 2015.) If you find lower price, double check that they are really 60 LED / m. That LED type is 5050, and that they have 3M stick tape and silicone water protection (IP65)
  Update April 2017.: Price is now better for WS2812b, you should be able to find 5m 60LEDs/m IP65 for $30 + shipping. (Stanislav, thanx for tip on price change)
• They need lots of power at 5V DC supply on packaging bag they are stated at 90W. But for 5 meters 10A 5V will be enough. I have measured 3A to 5A while all 5m were on. If you have shorter length maybe 5A supply will be enough. Max power calculation is 5m x 60 LED = 300 LED. each LED is 3 separate colors (Red Green Blue = RGB) so 3x 20mA. Total 300x60mA=18A current. Voltage 5V (beware not to use 12V!!) Giving total power 18A * 5V = 90W ! Have in mind that equivalent of regular bulb wuould be multiplied by e.g. 7, so max brightness would give you 90W * 7 = 630W (advice: do not stare directly at your LEDs!)

Hardware for player

Simple: Choose Raspberry Pi 2!

There are many options available now. If you have Raspberry Pi 1 you should probably think about new Raspberry Pi 2 because it have more memory and as they say it have 6 times faster CPU! You can consider any other PC capable or running XBMC (now called Kodi). I have tested Bannana Pi, and Banana Pi Pro, but they have problems with software support for embedded hardware video acceleration. So with those models you can expect problems while playing (software decoding) full HD video material.

What Arduino to choose for Ambilight (Adalight)?

Simple: Whatever you have, or order cheap Arduino Nano!

Beware! There are some project that suggest direct connection of Raspberry Pi to Arduino via serial pin (RX TX) or SPI. Some arduinos are working with 5V logic level and Raspberry is using 3.3V and you will probably require TTL logic level shifters.

Connection type between Raspbery Pi and Arduino: USB!

There are some projects suggesting that if Raspberry sends signal via RX TX pins they will be safe for Arduino but you should not risk if the Arduino sketch opens pin for output and gives 5V to 3.3V compliant Raspberry GPIO. The safe way is to connect them with USB cable (micro for Arduino Leonardo, mini for Arduino Nano or stanrad USB for Arduino Mega)

How to setup connection ?

When you connect Arduino Nano to Raspberry it will be detected as /dev/ttyUSB0. If you use Arduino Mega it will be /dev/ttyACM0. How to check that? Just login via SSH to your Raspberry and type: ls -al /dev/tty* which will give you something like:

crw--w----    1 root     tty         4,   8 Jan  1  1970 /dev/tty8 crw--w----    1 root     tty         4,   9 Jan  1  1970 /dev/tty9 crw-rw----    1 root     dialout   204,  64 Jan  1  1970 /dev/ttyAMA0 crw-rw----    1 root     dialout   188,   0 Mar 28 18:52 /dev/ttyUSB0 

you will see ttyUSB0 or ttyACM0 and then you will know what to enter in config files. If your USB serial is missing you can re-plug Arduino. You can always check with command: dmesg which will give you result like:

[   70.912700] usb 1-1.3: new full-speed USB device number 9 using dwc_otg [   71.032687] usb 1-1.3: New USB device found, idVendor=0403, idProduct=6001 [   71.032724] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [   71.032741] usb 1-1.3: Product: FT232R USB UART [   71.032756] usb 1-1.3: Manufacturer: FTDI [   71.032771] usb 1-1.3: SerialNumber: AH01KPB9 [   71.072351] usbcore: registered new interface driver usbserial [   71.072562] usbcore: registered new interface driver usbserial_generic [   71.072696] usbserial: USB Serial support registered for generic [   71.092861] usbcore: registered new interface driver ftdi_sio [   71.092992] usbserial: USB Serial support registered for FTDI USB Serial Device [   71.093405] ftdi_sio 1-1.3:1.0: FTDI USB Serial Device converter detected [   71.093584] usb 1-1.3: Detected FT232RL [   71.094575] usb 1-1.3: FTDI USB Serial Device converter now attached to ttyUSB0

What about Raspberry Pi Arduino USB serial port speed? Use 500.000 !

You must set the same speed in Hyperion (Boblight) configuration and in your Arduino Adalight sketch! Usually standard speed are multiply of 9600 like 115200, 230400, 460800 but it will generate problems for your Raspberry/Arduino! In our tests 115200 work ok, but it could probably be slow (just multiply necessary bandwidth e.g. 300 LEDs, each 3 colors, 1 byte per color,  30 fps … So you will probably need higher speeds. But you boblightd or hyperion will loose connections. Faster Arduinos will work better (eg. Mega can work at 230400, Arduino Due even better), but after lots of hours lost it looks like 500000 is best option. Why? Because it is multiply of CPU frequency and there are no lost clocks.

What about Arduino sketch?

Thanks to Hans Luijten here is the script that I have slightly modified here. Idea is to use Arduino to simulate "Adalight" device. Relevant part:

#include "Adafruit_NeoPixel.h" // DEFINITIONS #define STARTCOLOR 0x333333  // LED colors at start #define BLACK      0x000000  // LED color BLACK #define DATAPIN    5        // Datapin choose what you want or that is available #define LEDCOUNT   181       // Number of LEDs used for boblight 178 B1 E4, 180 B3E6, 181 B4E1 (iz boblight conf -1 tj 180), 182 B5E0 #define SHOWDELAY  200       // Delay in micro seconds before showing default 200 #define BAUDRATE   500000// Serial port speed, 460800 does not work – tested with Arduino Mega, Nano, Leonardo but 500000 is working with Nano #define BRIGHTNESS 70        // Max. brightness in % const char prefix[] = {0x41, 0x64, 0x61, 0x00, 0xB4, 0xE1};  // Start prefix ADA char buffer[sizeof(prefix)]; // Temp buffer for receiving prefix data

These last two lines are usually deal braker if you are not carefull. If you look at Hyperion code for device type "Adalight" :

_ledBuffer[3] = ((ledValues.size() – 1) >> 8) & 0xFF; // LED count high byte _ledBuffer[4] = (ledValues.size() – 1) & 0xFF;        // LED count low byte _ledBuffer[5] = _ledBuffer[3] ^ _ledBuffer[4] ^ 0x55; // Checksum

You will see that it reads configuration file and that last two values (0xB4, 0xE1) are required for my number of LEDS (first 0 last 180, totall 181 LEDs)

 

How to connect WS2812b to your Arduino?

In the previous Arduino sketch we have defined pin 5 as Data output pin. Signal should go through 480 Ohm resistor (in next segment there is explanation why the resistor is there) and then to RGB LED strip Data in pin. Remark: It DOES matter what end of led strip you use. There is marked Data IN and Data OUT pin for each led. Also, another recommendation: We have connected Arduino to Raspberry Pi over USB. It provides 5V to power Arduino. We should not connect 5V from LED strip. Idea is to "divide" RGB LED strip power supply from Arduino to avoid power supply problems for Arduino (we do not want to think about purity of 5V on LED strip). Conclusion: only two wires are connecting Arduino and LED strip. GND (ground) and pin 5 over resistor that carries data signal for diodes.

Why use resistor?

According to scheme, data OUT pit should not be connected directly to Arduino. Signal should go through 480 Ohm resistor. If you wonder why we not use some capacitor, remember that signal on data pin is 800kHz, and capacitor in series would block DC signal, and if used in parallel will distort square signals of zeroes and ones. If you put resistor it will attenuate peak levels… but that's not that we want. Purpose of resistor in series is that resistance of LED strip is much higher than Arduino output pin. Idea is to use resistor to balance impedance of both ends because of refracted signal. If you do not have 480Ohm (like me) remember that you can use e.g. two resistors of 1KOhm in parallel that would give you about 500Ohms. Exact value is not mandatory.

Troubleshoot Hyperion

When you plugin Arduino via USB to Raspberry, all LEDs turn on and stay that way. You can see /dev/ttyUSB0 or /dev/ttyACM0 but Hyperion is not working.

You must enter same communication speed and setup device type to "adalight". Also double check that two initial bytes in Arduino sketch are appropriate for number of LEDs in your hyperion config. Refer to Arduino sketch section.

Hyperion is working (command line test plays some effect or colour) but when you play movie LEDs are not resembling edge colours.

Probably Hyperion is not communicating with XBMC (Kodi). You do not need to install any plugin like with boblight but you must enter proper ip and port 9090 in hyperion config. Also Kodi must listen on port 9090. You can check that with: rbp2:

~ # netstat -lnp | grep tcp | grep 9090 tcp        0      0 :::9090                 :::*                    LISTEN      352/kodi.bin

Also doublecheck that System > Settings > Services: UPnP tab : Allow control of Kodi via UPnP Remote control : Allow programs (on this system and on other systems) to enable. Optionally turn off/on this settings and restart if necessary.

USB Serial port is missing when you type ls -al /dev/tty*

Replug Arduino USB cable. Check if Arduino LED is on. Sometimes Raspberry does not detect Arduino after restart. Comment if you have any idea?

Idea for future upgrade

Now everything works nice while you are playing video from your Raspberry Pi. If you play some content from e.g. Apple TV or game on your Sony Play Station then you can either choose some static colour or video effect from Hyperion library. But… there is even better solution for that… get some USB video grabber (composite or HDMI if your budget can support it). Connect it to your multimedia center (Raspberry Pi) and use it to grab signal while playing form external device over HDMI cable to you LED TV. More about that when video grabber arrives…

Gallery for OpenElec Hyperion/Boblight RGB LED project

UPDATE 2019:

Thanks to Raspori, here is the updated script where you do not need to enter a prefix, it will be automatically calculated. The only data that you need to update is your number of LEDs and data pin – that you have chosen. Here is the sketch:

New Hyperion Ambilight Arduino sketch