Recalbox RGB Dual

Story

Bring your CRT screens and TV sets back to life and play all your childhood games with RECALBOX RGB Dual!

We are Recalbox, a free solution that turns your Raspberry Pi nano computer into a retrogaming console supporting over 120 consoles and computosaurs (a.k.a old computers), and thousands of arcade games. As retrogamers, you know how transcendent it is to feel the nostalgia that takes hold of us when we replay all the games that rocked our childhood.

Playing with a PS4 or 8Bitdo controller on the living room OLED TV already allows us to rediscover and share the pleasure of retro gaming, but some of us have an insatiable thirst that compels us to go further and further in search of the closest possible experience to the original.

In this endless search, the display of the game is probably the most important point.

And what could be closer to the original experience than playing on your old CRT TVs (you know, with the SCART socket)?

1 - The purpose

The Recalbox RGB Dual project aims to allow everyone to play their favourite games on CRT TVs... WITHOUT ANY CONFIGURATION!

Many of you still have a CRT TV in the attic, and if you don't, CRTs can be found very easily, at a very affordable price, or even for free (by rummaging through your relatives' garages...)

Our goal is to get as close as possible to the original image and game experience on your consoles and arcade games. Let's keep it short and simple, the result exceeds all our expectations...

2 - Recalbox RGB Dual, what is it?

Recalbox RGB Dual is a small card (called H.A.T.) that clips onto your Raspberry Pi 4, 400, 3 or Zero2 to add a Scart output and a VGA output. If you already have an enclosure, we offer optional extensions that allow you to use Recalbox RGB Dual without clipping it onto the Raspberry Pi.

These two new Scart and VGA outputs allow you to connect your Raspberry Pi to any CRT TV or screen. From this SCART and VGA socket comes an RGB signal, considered the cleanest analog signal, compatible with all scart and VGA** CRT screens.

Pixel perfect is now within reach... Having the necessary hardware to play on a CRT is crucial, but at Recalbox the most important value is simplicity. That's why Recalbox version 8.0 has been 100% optimised to support the Recalbox RGB Dual natively, without any configuration required! It's very simple: just clip the Recalbox RGB Dual on your Raspberry PI, connect your scart plug, and let's play!

Recalbox RGB Dual prototype footage

Features

- Configuration chip

The configuration chip (eeprom) allows your Recalbox to detect if a Recalbox RGB Dual is connected and to automatically configure the system. This is 100% Plug and Play.

- The Pixel Factory

We have used the most efficient video signal processing technique to produce a razor-sharp image that is compatible with all television sets.

- The Boom Box

Both audio channels are filtered to smooth the sound signal, and ensure the best possible sound quality. Connoisseurs will recognise the filters of a class D amp.

- Power up

The 12V signal produced by the “Power up” automatically selects the correct channel on the TV when you switch on Recalbox.

- Automatic selection of the original display mode

The database embedded in Recalbox 8.0 contains all the information so that for each game launched, you can automatically enjoy its original display mode. For each console and each game:

• Resolution is 100% identical to the original resolution.
• Image refresh rate is 100% identical to the original refresh rate.

- Configuration screen

We have added a configuration menu that allows you to choose options such as the menu display mode, or to adjust the geometry of your screen.

- 50Hz Mode

For some CRTs that are not NTSC compatible (60Hz), it is possible to force PAL mode (50Hz) for all games.

- 240p Theme

The Recalbox theme has been optimised for CRT displays (240p and 480i). It optimises the space and allows for a more pleasant reading of the texts, even in such small resolutions.

- Overriding for power users

Recalbox RGB Dual is fully Plug and Play, but experts may fully override the display modes for every single game or console.

- 240p Test Suite

And if you're the picky type... We have integrated the 240P TEST SUITE system into Recalbox 8.0. This allows you to calibrate your screen to the nearest pixel for each console!

Another example?

3 - The case

We have designed a case that allows you to place your Rasbperry Pi 3 or 4 and the Recalbox RGB Dual. Available in limited quantities, it is available as an option when you purchase a Recalbox RGB Dual in the store.

4 - Development

The first prototype, soldered by hand, allowed us to validate the double Scart + VGA output and the feasibility of the project. It looked like this:

Since then, we've come a long way. 4 prototype models, hundreds of hours of research and development, and here we are: a zero-configuration experience, signals that are as close as possible to the originals, and an image that has NOTHING to envy from the original consoles...

This is the “laboratory" where we check and adjust: frequencies for each console clarity of the signals quality of each prototype

5 - The RGB signal, 240p, 15KHz and all the rest

Recalbox RGB Dual takes its name from the type of signal generated and sent to your TV. This signal is called R.G.B. (for Red Green Blue). At the time, this signal was considered the best analogue signal, and it still is today! Remember, when you bought the Playstation, it came with the yellow, red, white composite coaxial cable. This cable was far from honouring the console's graphics... That's why there were RGB cables (Scart) that were sold at a high price and that you absolutely had to buy in order to enjoy a quality image.

This is the same RGB signal that is generated by Recalbox RGB Dual!

When it comes to CRT displays, two terms often stand out:

• 240p, which means "a display of 240 active lines on the screen in progressive mode". This is the most commonly used display mode. There are dozens of other modes that are compatible with TVs, such as 224p for example. It is often noted with its refresh rate: 240@60p represents the 240p mode at 60 Hz
• The 15Khz, which represents the horizontal refresh rate, corresponds to the number of horizontal lines drawn per second. To calculate this frequency for 240@60p, you just have to multiply the number of lines to be displayed (240 + the lines we don't mention...) by the display frequency (60Hz)
• The 31Khz is twice the 15KHz 😀. The resolution of the games is 640x480 pixels with a progressive display, at 60 frames per second. This mode is only available for some consoles, arcade games and PC.

They like us!

They talk about us!

F.A.Q.

• What do I need to enjoy my Recalbox RGB Dual? A complete Raspberry Pi kit (Rpi4, Rpi3,RPi 400 or RPi Zero 2 with soldered gpio headers) with power supply, SD card and controller, Recalbox installed on the SD card, and a CRT TV 😀
• Can I connect both SCART and VGA outputs at the same time? No, this is not possible, the current limitation does not allow you to send the signal to more than one device. Moreover, the signal generated is only compatible with one or the other screen.
• Is it compatible with all CRT screens? Yes, the Pixel Factory generates a very clean sync signal to ensure compatibility with the maximum number of CRTs.
• My Recalbox is already in a case, what can I do? As an option, you can add a GPIO extension to your order to move the Recalbox RGB Dual outside your case.
• Are all the consoles and computers available on Recalbox compatible? Most are already compatible (all arcade games and over 70 systems), and future updates will add more.
• Is Recalbox RGB Dual compatible with other distributions? We leave it up to other retrogaming distributions to make their systems compatible with Recalbox RGB Dual.
• What about vertical games? Vertical games are supported on your CRT TVs.
• What about vertical displays? Since Recalbox version 9.1, the TATE mode can be activated from the TATE menu, allowing you to tilt your entire display by 90°.
• Which Raspberry Pi's are compatible? The Raspberry Pi 4, Raspberry Pi 3, Raspberry Pi 400 and Raspberry Pi Zero2 are compatible. The Raspberry Pi 400 requires a GPIO extension (available as an option when ordering)
• How big is the Recalbox RGB Dual? 56mmx65mm, it clips perfectly onto your Raspberry Pi
• What cables do I need? A SCART cable which is available as an option when you order. A GPIO extension cable if you already have a box for your Raspberry Pi.
• Is there a power supply to add? No
• Does it stay out in the open like this? If you are a Maker, we distribute free STL files to print your case in 3d on your printer or in a FabLab near you !