Hey everyone! We are back with everything that has happened over the last 4-5 weeks. There is a lot to pack in for this update, so sit tight and enjoy. 

Note: Some of the things we mentioned might be a bit technical, you can skip through them or ask questions in comments!

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Primary Hardware

I.MX95 Design at the last lap

In the last update, I had mentioned that we were close to releasing the I.MX95 Mainboard (EVT) for the Comet for manufacturing, but we still haven’t done that yet.

We are at completion but we are blocked because of the following reasons -

1. The production-qualified samples for I.MX95 from NXP will only arrive in the first week of July, due to delay with the fab.
2. There is a supply crunch with the PCB material we wanted to use, after two weeks of struggle, we have finally secured an equivalent material with our existing PCB manufacturer. They are on standby now.
3. During our reviews, we uncovered a challenge with the Suspend and Wake-up workflow. For the I.MX95, the M33 core is the main core, and handles the wakeup for A55 cores, this implied that all our wakeup signals have to route through the M33’s IO domain. This is leading us to re-route quite a bit on the PCB.

We have instead used this time to close every item we can and avoid long revision cycles later. Some of the things we were able to do during this time -

1. We finally got to the bottom of the WiFi issue, more on that below.
2. We tested the new LVDS to DisplayPort (Type-C), we have it working for 1080p60, and are now trying to scale it up to 4k30.
3. There was an issue identified with the internal USB Hub in our previous revision, we have rectified the same.
4. A number of improvements have been made to the overall mechanicals, certification readiness and provisions for LTE antenna.

We are getting ready to release this early next week, giving us enough time to get the PCB ready untill the samples arrive.

We have lift-off on the WiFi Issue ✨

In the last two updates I have mentioned we have had issues with the WiFI throughput. In the last month we identified two issues representing the root cause.

1. We were seeing packets stalling on iperf3 with our test wireless router in a noisy environment. With NXP’s help we identified that some off-the-shelf/commodity routers don’t handle WiFi 6 devices that use BA (Block Ack) burst. You can see the same stalling with other devices.

• When the IEEE Power Savings is ON, the WiFi chip kept going to sleep when downloading from a remote server over the internet due to the packet latency. This significantly affected throughput, with Power Savings OFF, we could easily reach 10-12 MB/s. We are talking to NXP on fixing this in their firmware.

More robust IO Connector

Our first versions used PC+ABS, commonly used in consumer electronics. Early in February, we noticed a weld line in the middle of the connector housing (What are weld lines?). While the parts initially looked fine, repeated attachment and removal cycles eventually caused cracks to develop along this lines.

Since then fixing this has been in our To-Do list. Remember the testing jig we showed last time? Over the last 2-3 months we have run below iterations -

• 1st Iteration: Molding process was tweaked and created an improved PC+ABS version. The results were better, but the weld line just shifted from top to bottom. FAIL
• 2nd & 3rd Iterations: We then explored alternate materials, we tested PA66 and PPS. PA66 showed noticeable flex during testing. PPS, on the other hand, felt exceptionally rigid and robust, giving us the mechanical performance we were looking for but a bad surface finish.

You can see the difference in flex for PC+ABS and PPS.

• 4rd & 5th Iterations: We locked in on PPS, but to solve the surface finish, we developed two additional PPS versions - (i) PPS with improved surface finish, (ii) PPS with UV Coating

The PPS with UV coating looks like a winner, we will know for sure once we test it too 👨‍💻.

More Mechanical Improvements with Revision 8

We are finalizing the 8th revision of the Comet’s mechanicals and primary design. Here are all the improvements we have incorporated

• No Tactile buttons on the edges: We’ve had a bad history with the buttons on the edges, they can break on assembly and disassembly. We are moving all of them to separate flex PCBs to ensure there is no damage to the main PCB.

• More Waterproofing: After the ports got all waterproof (last update), we are now trying to seal things with the buttons to further with the design for better day-to-day use. You can notice the compartment isolation for the buttons.

• Better ergonomics in the grip: The enclosure is much more rounded on the edges now for better grip. This also helps give it a good aesthetic overall and lose some of its brick look.

LTE & Antenna Design - the last straw

We have picked Quectel EM060K-GL as the officially supported modem for the Comet.

Primary features - CAT-6, L1 GNSS enabled and well certified with carriers globally. We are trying to get an eSIM integrated version for the Comet.

The LTE Antenna design is our last milestone before we shift to validation on the core Comet’s assembly. We have had some hurdles lately with an efficient antenna design without risking thermal efficiency and EMI radiation. I concluded lately that the three of them don’t like each other and are working on improving our mechanicals to strike a balance.

This is the location for the primary antenna, we are working on reducing the metal surrounding it.

Once we get the antenna design completed, we can list it out on the hub and let everyone know the bands we support, what performance to expect and which regions we will be certified for so that you can make an informed decision.

Extensions

Keyboard: Moving to ZMK for Firmware

We are moving from QMK to ZMK for our keyboard firmware. Primary reasons for our transition is that ZMK is built on Zephyr, and there are a lot more MCUs that support Zephyr than ChibiOS (QMK uses). ZMK is heavily being developed and, while it may not yet offer every feature that QMK supports today, we believe it has reached a level of maturity that makes it a viable choice for the vast majority of users.

This gives us greater confidence in long term hardware support, who knows maybe we'll even have a wireless keyboard extension someday?😬

Keyboard: Let's bring-in the Pointing Stick

Up till now, we had a trackpad on the Comet’s Keyboard extension. While a touchpad works great on a laptop, the available space on our extensions is much smaller - especially vertically. During testing, we found that moving the cursor across the entire display often required multiple swipes, which can quickly become frustrating in regular use.

That's when we started looking at an alternative approach: the Pointing Stick, similar to those found on ThinkPads and some Dell laptops. Unlike a touchpad, a Pointing Stick works by sensing pressure rather than movement.

We built an experimental prototype using four miniature strain gauges arranged around a central stick, the results were promising and we got hooked in.

When studying off-the-shelf solutions available in the market we realized that by designing a PCB with printed thick-film resistor PCB is all that it takes. We are sending them for manufacturing!

Gamepad: Extension goes Pro

This one I am particularly proud of, the Gamepad finally got a lot more love. Especially now that I.MX95 has a much better GPU for handheld gaming.

Analog Stick: One of the most requested features has been a dedicated analog joystick, and we're excited to share that it's now part of the design with a slightly bigger extension to have better spacing for the buttons. We have just ordered some Hall and TMR samples.

Shoulder Buttons: But that's not all. We've also added shoulder buttons, making the Gamepad Extension much more capable for modern gaming and giving it a more console-like feel.

Pointing Stick: And if you've been looking closely at the latest renders, you may have spotted another surprise at the bottom: a Pointing Stick. We ideally would have loved a second analog joystick but there is not enough space (especially because of the pogo pins on the back).

Originally, that lower position was originally planned for a small trackpad to help with camera control in 3D games. With the trackpad, we would have the same issue as the keyboard, so why not re-use the pointing stick here. We will optimize the nub shape and sensitivity differently for the gamepad.

Type-C Support: We've now added a USB Type-C port to the Gamepad Extension.

This unlocks several exciting possibilities. You can now comfortably game from a distance while Comet is docked on a stand or connected to a monitor or TV, making couch gaming much more practical. It also opens the door for multiplayer gaming, where multiple Gamepad Extensions can be connected without being physically attached to the device.

Even better, the Gamepad Extension can now be used with other compatible devices as well, effectively turning it into a compact standalone controller that fits right in your pocket.

We also 3D printed multiple layout and ergonomic prototypes throughout the process. Being able to physically hold and test different button layouts gave us valuable feedback that simply isn't possible to get from CAD models alone.

Gamepad: Re-engineered buttons

Over the last few months, we completely reworked the internal button structure of the Gamepad Extension. This included changes to the silicone membrane, button geometry, and the enclosure features that support and guide the buttons during operation.

While working on this we realized how much the silicone membrane’s dimensional stability and hardness matters. Even small changes in shore hardness makes a noticeable difference in how a button responds.

To find the sweet spot, we manufactured silicone membranes with multiple shore hardness values and tested each one extensively. Some felt too soft, some too stiff, and some simply didn't provide the feedback we were looking for. It took several rounds of testing before we found a combination that felt right.

Here is video showing how the new buttons compare to a Switch’s Joycon -

Software

Mainline Linux tested on I.MX95 EVK

We mentioned in the previous updates that we are moving towards mainline Linux and U-Boot (bootloader) for our officially supported images. While we were able to get everything working for I.MX8M Plus, we were waiting for the Comet’s I.MX95 boards to arrive to get started on mainline support. Because of the delay, we instead started getting everything to work on the FRDM-IMX95 EVKs.

Here is the status of everything working on mainline with I.MX95. The Linux contributors and maintainers are the real heroes 🦸‍♂️🦸‍♀️ without capes.

More demos on I.MX95 EVK

Now that we have operational I.MX95 EVKs with Mainline Linux and Mesa, I was very curious to see how the Mali G310 performs. The Mali G310 is a v10 Valhall GPU with well-supported Vulkan and OpenGL in Mesa.

Here is a demo of Minecraft Classic running on Chromium at 1440x900 resolution.

This is SuperTuxKart (natively ARM) running on 1920x1080

I am going to run a lot more demos in coming week, will keep sharing them on Discord / Matrix.

OpenGL ES 3.0 for Etnaviv (I.MX8M Plus) is now underway

We have partnered with Igalia to further improve the GPU driver (Etnaviv) for the I.MX8M Plus in getting it compliant with OpenGL ES 3.0 specification. The development work got started in mid May and Christian Gmeiner as been actively pushing features for GLES 3.0 support for the I.MX8M Plus GPU.

He has recently raised a merge request for 128bit format emulation that has helped close to 436 deqp tests to pass (see below)

More progress on the Launcher

Remember our on-going crusade to hand-craft the Launcher? We have made strides of progress with it, and we now have a working engine and API that we have started using to build Launcher interfaces.

Here is a quick demo of the Work-In-Progress Lockscreen built using the new framework. This performance without even having damage tracking.

New Optimisations that we have made:

• Cached lay-outing using taffy. The tree is built at compile time using the type system rather than at runtime with the option of making certain elements dynamic.
• The UI is absolutely reactive, nothing will happen unless something has changed.
• The change propagation also can be optimised by the developer instead of automatically being detected. For example if we want to change something 100 times a frame, the developer has the option to not change the layout 100 times and do it manually by opting out.
• Visual changes and Layout Changes are handled separately.
• Damage Tracking is implemented.

You can follow the development here: https://github.com/mecha-org/mecha-wayland

Native Apps development underway

We have been building multiple apps for the Mechanix OS, since last month we have been testing them on device and pushing the integration further. These apps are based in Flutter, and we are using Flutter-Rust-Bridge every time we need to access system internals. Some key updates -

Browser: We have integrated Chromium Embedded Framework (CEF) within Flutter to build a the default browser app for Mechanix OS. CEF gives us a solid web rendering and javascript interop and flutter lets us customize the shell.

Terminal: Similar to browser we have integrated Alacritty for the terminal emulator, giving us a full OpenGL rendered terminal within Flutter. We can use Flutter for multi-tab support and input system optimized for the Comet.

We are not very focused on UI design but rather functionality and integration. You can check the demos available here and you can find the code in the pre-release branch of all mechanix repositories on our github.

Supply Chain and delivery

How delayed are we?

I am sure most of you would have figured it by now, we are delayed in our planned delivery timeline. We had originally planned for validation to close in June, and pre-compliance by early July. All the factors contributing to the delay have been mentioned above, we are trying to work around it as best as we can to deliver a product that outperforms your expectations.

Validation & pre-compliance is critical for us before we sign-off any tooling because tooling is permanent.

As of right now we see a 4 weeks delay, from our original timeline. This is assuming that the next steps for pre-compliance and validation goes well and we don’t hit any roadblocks further.

What’s upcoming?

We are still sticking to our hardware design freeze by end of this month (June). During the next 2 weeks we want to close on as many items we can and freeze the designs for the Comet and its extensions. Some of the key items planned in June and July are -

June

1. Release the I.MX95 EVT design by early next week for PCB Fabrication.
2. Start the I.MX8M Plus PVT design matching the Comet’s Revision 8 design.
3. Finalize the Keyboard Extension - layout, buttons
4. Complete the LTE antenna design and make the LTE addon available.
5. Start the manufacturing of close-to-production housing parts for Revision 8 validation.
6. Align the certification partner for pre-compliance and compliance testing.
7. Prepare the Gamepad and Keyboard DVT prototype PCBs matching new design.

July

1. Align the manufacturing partner for production tooling.
2. Run the PCB Assembly for I.MX95 EVT once the boards and the processor samples arrive.
3. Perform hardware validation on a fast-track basis
4. Validate the mechanical design
5. Start pre-compliance verification for critical testing requirements
6. Start production tooling for all plastic, metal and silicone parts
7. Manufacture the I.MX8M Plus PVT

A lot of our delivery timeline will depend on successful pre-compliance, because the actual compliance takes another 8 weeks at minimum, but we can get started with tooling in parallel.

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We are done with last month’s update! See you with the next one. I am hoping to do a video presentation 🎥 for next month with the Comet’s revision 8.

It is not all work at Mecha, here are glimpses of our team playing it out on the field!

See you in the next one!

Yours truly,
Shoaib & the entire Mecha team