Retro Lite CM4: Raspberry Pi CM4 in a Switch Lite

[StonedEdge]

Hi guys,

Perhaps a few of you have seen this floating around the web, but I'm currently working on a cool retro gaming console project dubbed "The Retro Lite CM4" which is essentially a CM4 inside of a switch lite shell that is custom machined - I thought some people may like to see it if they haven't already. It'll have a bunch of cool features, including proper USB-C PD charging, internal USB hub, HDMI out and other cool features that I'll post below. It's still a work in progress and currently we only plan on making 2 of them, but that may change if we get the design to a point that it could be produced on a larger scale to sell to the public, although we don't really have any plans for that at the moment.

Both of us aren't engineers or don't do this full time, we are just passionate gamers who enjoy electronics/CAD/PCB design.

Retro Lite CM4 Specs
5 - 5.5" LCD IPS screen (parallel interface)
Dual Switch Joysticks
Stereo speakers
Resin Cast buttons and dpad
Anodized aluminum housing
Custom Copper Heatsink and fan
Raspberry Pi CM4
AIO PCB including arduino (for control input), battery management, Back light boost converter and audio amplifier
USB C Charging and data transfer
External HDMI output
4000mah battery

Here's a couple of pictures of it in its current state. If you've got any questions, feel free to let me know and I'd be happy to answer!

[Spyder]

Man that is so sweet. It looks gorgeous
Are you adding a safe shutdown? Any plans to release files for people to build their own?

[StonedEdge]

Man that is so sweet. It looks gorgeous
Are you adding a safe shutdown? Any plans to release files for people to build their own?

Hi - thanks, glad you like it!

Yes, there will be a safe shut down. It's pretty easy to do on the Pi. At first we we're going to drive a GPIO high but realized that the CM4 can only handle 3.3v +0.5 on it's GPIO, so we will most likely just use an internal pull-up and drive it low with our microcontroller to initiate safe shutdown. The portable will be turned on by holding a button for 1.5 seconds and safe shutdown will initiate on holding the button for longer than 3.5 seconds when the system is powered on. It will then take around 15 seconds to shutdown (i.e cutting power from the boost regulator).

There is no current plans to release CAD files or models as the case really doesn't work for 3D printing - the tolerances required for the triggers are very unforgiving and the case is designed in Solidworks with machining in mind, so I think a lot of hobbyists will be limited even if we released files. That being said, we are considering "kickstartering" the project to raise funds for a proper injection mold if things work out and we get enough interest, so it may be sold as a kit in the next few months.

[Sushi]

Did you machine it yourself? It looks immaculate.

[StonedEdge]

Did you machine it yourself? It looks immaculate.

It's been a joint effort between myself and another friend of mine who owns a 3-axis CNC machine. I've been working on the PCB designs and he has done the case, so I didn't machine anything or do any anodizing. All the credit goes to him for the case work!

[Max3D]

This is amazing, did you source the AIO PCB or is it custom?

[StonedEdge]

This is amazing, did you source the AIO PCB or is it custom?

It's all custom designed in EAGLE.

[StonedEdge]

Has this project been completed? I'm looking forward to the actual results.

Not yet. I'll be sure to post the final results when it's done! I made a few mistakes with the PCB that need to be revised. That and the fact that CM4s are not readily available due to the silicon shortage has extended the project.

[StonedEdge]

Figured I would update this thread as we now have some progress made. CM4 boots well and video is working perfectly.

A couple more things to do but I would say we are close to completing our first prototype towards end of August.

[StonedEdge]

Hi all. It's been a while since I posted about this project here (I have been regularly posting on the sudomod discord about it), but the project is very much near its completion. My project partner and I have made a tonne of progress and I'm excited to share where we've gotten to.

I'll post a few pictures below for those who want to see the final product. We're working on putting together the resources to sell some kits, but the CM4 is in short supply, which makes it difficult to make any real progress. I don't want to make any promises right now on anything as nothing has been confirmed, but we're trying our best to source parts from several suppliers at the moment, put together a website, make it as affordable as possible as well as getting samples made. I think it's important we mention that all trademarks from Nintendo will be removed on the final kit version too, as beef with Nintendo is not something that seems all that fun to go through. I'd like to thank Helder for assisting in getting the custom batteries made, kiteretro for general advice and more people I'm probably forgetting.

Current features of the handheld now include:

- Raspberry Pi 4 SoC: Broadcom BCM2711 quad-core Cortex-A72 @ 1.5GHz (overclockable to 2.1GHz)
- 2GB of LPDDR4-3200 SDRAM
- 5.0GHz IEEE 802.11b/g/n/ac wireless, Bluetooth 5.0
- 800 x 480 HDMI video output (HDMI0 - internal)
- 1080p 60fps HDMI video output (HDMI1 - external)
- Switched to a tempered glass screen protector instead of painted plastic, now is printed
- Fuel gauge for accurate battery SoC monitoring
- Custom software stack specific to the Retro Lite hardware
- Custom menu activated by pushing select + R3, which allows you to calibrate the sticks, see various things like CPU temp, bring up an on screen keyboard for input, and more
- USB-C PD charging capabilities up to 15v (1C charge rate at 2A)
- Stereo Audio Output
- Headphone Jack
- 4000mAh custom lipo, courtesy of Helder
- Dual shoulder buttons (L, R, LZ, RZ)
- Safe software/hardware shutdown to prevent corruption to the SD card
- USB 2.0 2-port downstream hub

Here's a bunch of photos that I've taken so far. I'll throw them in a spoiler tag so as to not clog up the thread.

SpoilerShow

We're always open to suggestions and improvements, whether that's on the software side or hardware side of things too. Eventually, once the code base is complete, we will be uploading all of our code to GitHub so that others can reference it when building their own designs.

Cheers,
Stoned