GreenAntz RGB to component transcoder

[net_terminal_gene]

Posting a review because Andrew (Zebidee) absolutely deserves it.

I picked up a GreenAntz v1.95 to run VGA/RGBHV → Component (YPbPr) for Batocera-CRT-Script into a consumer CRT (Philips 20PT6341/37). The results are exactly what I was hoping for. Excellent color saturation and depth (not washed out like some transcoders), a clean image, and rock-solid sync. Once dialed in, it just works.

I did end up discovering that my first unit was faulty. After a few hours of runtime, the image would start to flicker and eventually become unstable. What really stood out, though, was how Andrew handled it. He was prompt, patient, and genuinely invested in figuring out what was going on. We went through power, sync, and environmental variables together, and he did a great job explaining the possible causes in clear, technical terms without hand-waving.

Once he identified the root cause (a build-related issue on the PCB), he didn’t hesitate. He built and thoroughly tested a replacement unit, ran it for extended periods to confirm stability, and shipped it out. The replacement has now been running 100% stable for me with zero issues.

This kind of transparency, communication, and follow-through is rare, especially with small-run hardware projects. Andrew clearly stands behind his work and cares about the community and the product. I wouldn’t hesitate to recommend GreenAntz to anyone looking for a high-quality VGA to component solution. 

[Zebidee]

Thank you Mikey! So glad the replacement is working out right for you.

Turns out the issue was caused by me not properly cutting a tiny bit of trace beneath the blue sync LED. GreenAntz is in continuous development and the boards I've been using were never designed to have a sync LED, I it is retrofitted into the design. When I get some new boards done the sync LED will be incorporated as a standard feature, no hacking required.

Now that they have the sync LED, I find it invaluable for troubleshooting setups.

OTHER NEWS

The latest design (v1.95) restores the slide switch to select between Csync and Vsync inputs! I had removed the switch for v1.94 as I was happy with GreenAntz "autoswitching" to composite sync when there is no Vsync present, I deemed it unnecessary. Unfortunately CRT_emulator does *NOT* turn off Vsync signal when composite sync is enabled. As noted in my earlier post, this could potentially result in "unrecoverable" situations, requiring rebooting into safe mode and uninstalling drivers.

The restored slide switch forces composite sync mode mode when enabled (it actually disconnects the Vsync input and "blanks" it, pulls it to logic "high").

[newshrimp]

Can't wait to try this out

[Austin_MVP]

Hi! Learning about ways to use Batocera on a CRT has led me to the Discord server/GitHub page and now here.

I have an NTSC Sony Trinitron CRT with component inputs. Hoping to get a Batocera setup running on it in the not so distant future.

[metadatum]

awesome to see hardware for analog signals still being developed and improved today.

[zone72305]

This looks promising. I recently got into the CRT rabbit hole and wanted to connect my PC to the CRT without compromise. Though I'm wondering if my PC can output 240p/480i first. I have a AMD R5 200 series card on it. I'll look into that too.

[Zebidee]

A quick update:

The new GreenAntz (v2.1) will soon be available!

GreenAntz v2.1 is fully SMD (surface mount design), I've done away with the through-hole components where possible. This means is is much smaller than the old GreenAntz, about 60% or the original size, but retains all the same great features:

- accurate composite sync generation and integration into Y signal at appropriate levels
- sync autoswitching (and manual override switch also included)
- precise voltage regulation (avoid "flickery" colours).
- optimised video amplification (more consistent, right levels, fully saturated colour)
- optional low-pass filter (9.5Mhz 6-pole butterworth) available
- optional 5v landing site for innovative project applications (e.g. inside a JAMMA cab, powered by same DC PSU as game board)
- PCB-style offset legs allow screw-in mounting (ideal for arcade cabs)
- Pots to allow precise tweaking of Y, Pb & Pr outputs.




Smaller size less than 60mm wide, and about 75mm long (including jacks).


GreenAntz v2+ also includes a pot for adjusting Pb output, so now you can adjust all three video channels (Y Pb Pr) to suit your own needs and preferences. These pots adjust video OUTPUTs, rather than throttling the RGB video INPUT signals like some transcoders do. This means there is no loss of picture information.

Going to smaller size and SMD components also seems to have provided some other less obvious improvements, including less signal interference and issues like parasitics often associated with through-hole builds. My assessment of this is perhaps less scientific than I'd prefer, except to note that when it works, it usually just looks good and works as it should.

Finally, despite the reduced size and profile of GreenAntz v2+, you can still provide alternate 5v power.


 
Screw terminals (5.08mm spacing) drop right in!


The images shown in this post are all of GreenAntz v2.0, a version only used for prototyping (green PCB). I am not intending to sell any of those. These prototypes have all been hand soldered and I can attest that soldering SMD boards takes about the same time as the old through-hole boards, best part of a day. Most of that is in the setup (solder paste and placing parts), the actual soldering (mostly with hot air) doesn't take that long. Would have saved a lot of time if I'd remembered to order a stencil (for applying the solder paste).

Anyway, within a week or so, I expect to have the new GreenAntz v2.1 boards in hand.  These ones I will be selling. The v2.1 boards will come partly assembled (~80%) by pick-n-place machines at the factory. This means I can turn them around quickly and into your hands faster.

If you want to get in early to order your GreenAntz v2.1 then please send me a PM! Don't forget that you must make at least one post before sending PMs.

PS - I am also currently investigating development of some kind-of enclosure or box. Follow this thread for developments!

[buttersoft]

Sweet, dude. Time to design a 3-d printed case, eh

[Zebidee]

Ond did a design a while back, and you can download the files from this thread. They could be adapted for the new slimline GreenAntz.

The only real difference is the new v2 models are not as wide.

In any case (no pun intended), I'm currently in discussions with potential suppliers.

I kinda like anodized aluminium, or plastic/polymer, but it may come down to price.

Next big question will be: what colour?

 

Sweet, dude. Time to design a 3-d printed case, eh

[Ond]

I'm on board with this -again-  . Great product, better than what else is out there imo. Anodized yellow cases please!

[Ond]

New GreenAntz 2.2 case design for Zebidee to mull over  Well it is green!

[Zebidee]

Wow, it looks very nice indeed Ond. Love your work, thank you so much!

Oh, I'm definitely mulling! Mull mull mull mull... "The Mouli Mullamatic, it work liiiiiiiiike magic", old advertising jingle some mates came up with for a music school assignment, they'd sing it a capella all the time, ear worm still stuck in my head after 25+ years....

I think it needs "GreenAntz" text there - if stylised is too hard, then simple text would do.

I've been juggling ideas to extend the LEDs to those holes. In theory the legs could extend from the PCB, so that the LEDs actually reach those holes themselves.

Alternatively, some 3mm fibre optic. Glue one end into the hole (carefully, so it lies flat) using either clear epoxy or even just superglue (gotta be careful with that stuff). A little pre-shrunk heat-shrink tubing, slightly recessed, could help it sit properly and increase surface area for glue to hold. The other end can be have more heat shrink tubing, longer, that also extends over the head of the LED, pre-shrunk to fit. Slip it on and screw the shell halves together. Maybe another big blob of glue or silicon inside the shell to hold it there.

Feels a bit fussy and fragile though, at least where it would be glued to the shell. Obviously I will have to experiment.

If we do fibre-optic tubing then maybe the LEDs can be the GreenAntz' eyes? That would be pretty wild.

Oh, and shell colour doesn't have to be green despite the name lol.

I'm already getting some prototype shells printed, basic version of this design (no logo, wings, LED holes). Will share some pics here in a few days.

[Ond]

You're welcome  Note, the case has been designed from scratch although I did use your supplied model as a reference.

More pics including added text.  You can see how the moldings work including the tubes to LEDs.

...and in my preferred color

I don't recommend any tubing/optical fiber etc.  The LEDS will be plainly visible when viewed from above which means less work for you. In testing I've found that white optic tubing does not work very well anyway.  I'd keep the text under the logo plain. Stylized font will look too much IMO.

[buttersoft]

nice case design, Ond!

Zeb, i like to use round perspex rod for light pipes on my designs. Hole tolerances on the print can sometimes be tricky, but once you dial it in you just cut a short length of rod, file it flat on the top end, and press-fit into the hole.

[PL1]

Looks great, Ond. 

Instead of the current straight-sided LED cylinders, you may want to consider using tapered cylinders.

One way is to slightly increase the outside hole diameter so there is a (5-15 degree?) larger viewing angle -- no light pipes needed.

Otherwise, you can add a thin, 6-8 mm tall vertical slit across the bottom of the LED cylinder walls (red lines) and use a very slight taper on the bottom 1/4 or so of the cylinder.
- The slit will allow the bottom of the cylinder walls to flex a bit for better friction while making the tolerances less critical.
- This makes it easier to insert the light pipe into the top then press it down for a flush friction fit.
- For more flexibility, you could add a second slit so the bottom is divided in quarters instead of halves.


Scott

[Zebidee]

Looks great Ond! The text font looks good too.

I had noticed a bunch of small things were different, and that is all good. I can see why you rebuilt the model. Thicker, longer inner shell on the top piece is good. Extended to meet the PCB layer. Speaking of...

The PCB layer is 1.6mm thick and must be accommodated. The top level looks right, but the model seems to be assuming zero PCB thickness. Think it just means lowering the screw posts, and corner/edge support bars, on the bottom piece. This issue is more obvious when looking at the USB/VGA ports (circled yellow).

The bulk/box/body part of the RCA ports is right up against the edge of the PCB, making me worry that the thicker inner/lip part of the top piece may bump into it. On my prototype model I sliced about 0.3 mm off the lip there. You made thicker! Anyway, you probably wondered WTF when looking at the model I sent, but that is why. I may have been worrying about nothing, it might all fit together fine anyway because the material is flexible enough etc.

Anyway we'll see when the prototype shells are here, and you'll know more once I send you a v2.2.

Thinking some more, the wings may need to be a little larger, the holes up to 4mm diameter, and moved a little further away from the body. Circled in red below. Checking again, some of my favourite cab screws (and used extensively by LAI), on closer look, actually have 4mm thread and just over 10mm wide heads ("button head needle point", various lengths, bought at Bunnings over a decade ago). Even my 2nd favourite cab screws have like ~8mm wide heads. Pic attached.

I hear your advice concerning LEDs on board too. I will probably experiment with fibre a little anyway, and ordered some 3mm fibre last night before hitting the pillows (or reading your response). So it is coming anyway. I can make the LEDs considerably brighter by just changing the current-limiting resistors.  Currently ( ) their brightness is throttled quite a lot. Designed to be visible but not distracting.

Butters, thanks for the tips about using perspex rods with LEDs, interesting alternative.

Thoughts welcome 

PS - Nice ideas Scott!

I like the idea of closing the hole with a light pipe, to avoid damage from spilled sodas and such. A drawback is that the LEDs would be less visible from the side, such as when installed on the in-side a cab.

It also occurs to me that these contexts are mutually exclusive - you don't really need an enclosure in a cab anyway, and you don't really have side-visibility issues on a coffee table. Even so....

Your side slits idea might further allow a compromise as it would allow the LEDs to be visible from the side (barely), while still mostly protecting from unplanned soda events.

Another thought is that LED visibility would not be an issue if the enclosure was transparent! 

[Ond]

All good. I have in fact allowed for the PCB thickness in the design. There is a gap there. I'll check your other requests soon.

[PL1]

the wings may need to be a little larger, the holes up to 4mm diameter, and moved a little further away from the body.

Agreed.  Better 6mm too much room between the screw hole and the side of the case than 1mm too close.
- Might be good to allow enough room for a socket if anyone wants to use a bolt/hex head fastener.

I like the idea of closing the hole with a light pipe, to avoid damage from spilled sodas and such. A drawback is that the LEDs would be less visible from the side, such as when installed on the in-side a cab.

How deep you install the light pipe might make the LEDs easier to see.

If you press the light pipe in so it is flush with the surface of the case, it will definitely be harder to see at a low angle.

If you start to put in the light pipes then place the case cover face down on a hard flat surface and firmly press down in the center of the ant head logo, that should seat the light pipes so they stand proud the same amount as the ant head logo does, increasing visibility.
- If this is how you want to proceed, consider adding an outline rim on the case the same height as the logo.  That would also make it easier to 3d print face down.

Your side slits idea might further allow a compromise as it would allow the LEDs to be visible from the side (barely), while still mostly protecting from unplanned soda events.

I wasn't suggesting slits in the side of the case, just a 0.5 mm wide by 6-8 mm high slit in each LED cylinder (red lines in this pic) for greater flexibility and friction to hold the light pipe firmly in place without adhesive.




Scott

[Zebidee]

I 100% believe you, but cannot see it in these images. Maybe a different perspective would help.

All good. I have in fact allowed for the PCB thickness in the design. There is a gap there. I'll check your other requests soon.

[Zebidee]

I was thinking along the same lines, about installation depth, and will do some experimentation.

Yeah, I was off on the completely wrong track about the slits. I see what you mean now.

How deep you install the light pipe might make the LEDs easier to see.

If you press the light pipe in so it is flush with the surface of the case, it will definitely be harder to see at a low angle.