SaturnDave (Sega Saturn, SHIRO!)

GrechTech Retro Rosetta: A Multi-Player BlueRetro Adaptor

GrechTech has recently made available their new RetroRosetta, a modular Bluetooth receiver/controller adaptor designed for retro systems with a focus on robust multi-player support and an aim to avoid e-waste and tackle accessibility issues. The RetroRosetta supports a myriad of different game consoles and is made possible thanks to the amazing BlueRetro project by developer Darthcloud.

The GrechTech RetroRosetta (or GTRR for short) is a universal platform with a simple internal pin header that can be used to connect to almost any console with setups ranging from 1 to 4 cable outputs.

Besides the configurability of it, another motivating factor in the design choice of GTRRs connector was the ability for people to easily and cheaply make their own DIY adaptors for any system at home, with cables salvaged from old broken controllers, extension cords or replacement cables, as the cables require no active circuitry to connect to the GTRR platform. They simply need to be cut and crimped, and they are good to go.

A big reason for GTRRs cabled, multiplayer approach via a standalone box, was that the ESP32s used in all BlueRetro devices can, at times, be somewhat limited as far as antenna power & range goes, especially in particularly large or noisy rooms. GrechTech wanted a device that could stand on flat surfaces, so that people could use long cables, and/or extension cables, to put the base unit somewhere higher up or closer to them, to improve signal performance.

Additionally, many of the consoles that the GTRR supports are quite old, with relatively low limits on their overall system power consumption. Systems with 7805 variants are limited to 1A, while others have strict current limits to the controller ports, not to mention the fact that many of these systems have aging power supplies and capacitors.

The ESP32 used for BlueRetro hardware is relatively power hungry, while average power is fairly low (around 100mA), and the power for the antenna can cause some quite large and sharp spikes in current draw, with peaks close to 500mA (close to what some retro consoles pull entirely). In order to minimize issues in multiplayer scenarios, the GTRR avoids the need for people to connect multiple ESP32’s (basically several standalone dongles) to their old consoles, in favor of a single antenna system maximizing compatibility and minimizing strain on aging power supplies and capacitors, while also having the option sharing power from 2 controller ports to one antenna.

In addition to that, the GTRR can also have a USB cable attached to provide external power, avoiding load on the console power supply entirely!

Another key factor GrechTech had in mind with regard to his design approach was previous experience with some 8BitDo adaptors, where two or more of their Bluetooth dongles being used simultaneously next to each other (as would be the case in multiplayer scenarios) would often result in performance issues (lag, disconnects, etc). This primarily seemed to be caused by a downward spiral from the two antennas competing with each other, raising their antenna power/strength to try to overcome the interference coming from the other dongle, while inadvertently raising the interference transmitted to the other, and vice versa, until a controller would disconnect, and the process would start over.

For these reasons, a single antenna approach seemed to be the most reliable solution, and a commitment to single antenna was made early on in all scenarios for optimal Bluetooth performance. However, as far they are aware, this seems to be way less of an issue with BlueRetro dongles than it was for the 8BitDo ones.

All in all though, the overall feature set of the BlueRetro functionality should be identical between this and most available dongle solutions, as they use the same firmware running on the same key hardware elements. The biggest consideration for consumers will be how the device fits into their overall setups. While standalone Bluetooth dongles may look more aesthetically pleasing, the GTRR remains focused on performance and flexibility, while empowering users to create their own cable adaptors, if desired.

GrechTech Links:

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