GreenAntz RGB to component transcoder

[Zebidee]

Very nice work! 

Thanks Emphatic!

Many people ask "Can I use GreenAntz to turn a component TV into a monitor for an arcade cabinet?"

The answer is YES and I'll give a brief overview.

Firstly, you'll need some 500R (500 ohm) potentiometers in series on the RGB inputs to GreenAntz. This is to bring the higher voltage arcade RGB signals down to typical SDTV levels ~0.7vpp. I chose cermet multiturn pots for this as they are much better quality and easier to adjust than the standard cheap carbon film trimpots, which are very fiddly and break easily.

You can then run the RGBS+Ground signals through the pots and into the GreenAntz using a VGA (male) header with screw terminals. You won't need any resistors or pots on the sync signal when using the VGA version of GreenAntz.

You can do similar thing with the SCART version of GreenAntz, but you will need to put a resistor (~500 to 1000 ohms) on the sync input.

   


Secondly, depending on your GreenAntz power supply, you may see significant interference as the ground loop is shared with the JAMMA. Better power supplies minimise this issue, but the simplest solution is to take the 5v directly from the DC PSU instead! You can do this with a simple cable made from 2 wires with female spade crimps on the PSU end, and tinned wire at the GreenAntz end. Alternatively, you could use fork/U connectors instead of female crimps or a 4-pin molex header if using an ATX type power supply.

Pop a standard 5.08mm pitch 2-post screw terminal onto the GreenAntz (using the pads/holes that are already on the PCB), or even solder directly to the PCB. Make sure to mark the ground terminal with a permanent marker so you don't get the wires mixed up (I marked the terminal after taking the photos below, but you can see it marked in the middle pic above).


   


Finally, most arcade PCBs output composite sync, so you will need to enable composite sync input on the GreenAntz. In current versions you just flick a switch. However if you have a very early build of GreenAntz that doesn't support composite sync directly already, please refer to the FAQ above for info on how to make it work. You can also contact me directly and I'll help you.

If you have a SCART GreenAntz unit it supports composite sync already automatically (except you will need to add a resistor to sync input as noted above).

Here are a few gratuitous screenshots to keep you happy. for more information and screenshots check out my post on making the supergun with GreenAntz to test PCBs. Please contact me directly if you want to get a GreenAntz unit.

[bobbyb13]

A-ha!

Brilliant.

I remember you saying this was possible but I have been too busy to have time to try it.

Maybe soon I hope?

[marcelinho1979]

Great converter!  I need one! 

[pixelss]

finally found a solution to my upcoming cabinet that i will like to use my CRT tv with my desktop.

[mamenewb100]

Cool to see such creativy. Doing things others haven't.

[bobbyb13]

Great converter!  I need one! 

Yes, and yes.

I have 5 and they just work.
Great support from that Zebidee guy too, if you need it.

Find yourself a component input tv and make your mame life grand.
Don't worry that it is coming from a far away land.
It will get to you (even if it goes through New Jersey on it's way to Hawai'i...?!)
 

[Zebidee]

Great converter!  I need one! 

Yes, and yes.

I have 5 and they just work.
Great support from that Zebidee guy too, if you need it.

Find yourself a component input tv and make your mame life grand.
Don't worry that it is coming from a far away land.
It will get to you (even if it goes through New Jersey on it's way to Hawai'i...?!)
 

Thanks Bobby!

I don't think the parcels really go to NJ. Bangkok port area has various "free trade zones" where foreign companies can operate with tax concessions and other investment incentives. Part of it involves being able to declare their warehouse as domestic soil, to a limited extent (not like an embassy, but for tax/duties/payroll etc.). Thus why the tracking may show a parcel going to NJ, even if it never physically goes there (or does it!!!!     I'm just playing with your brain now).

[fsmith2003]

I must have one of these!  How do I get my hands on one?  I cant seen to send PM's on here yet I suppose because I am new to the forum.

[Zebidee]

I must have one of these!  How do I get my hands on one?  I cant seen to send PM's on here yet I suppose because I am new to the forum.

Hi fsmith2003 and welcome to BYOAC! The forum lets you send PMs after you have posted, so you should be good to go now.

[retrometro]

How much is this thing?  I can’t follow this thread

Special price for you Pbj (and other members), only US$45 + courier shipping ($15 to USA via USPS). Price for strictly limited time, basically until I can be bothered listing some on our favourite online marketplaces.

Hi, I just came across this thread and I love that there's another alternative to Retrotink's overpriced RGB2COMP.

Do you have a site to order and what kind of changes have their been since this mid 2021 post?

[Zebidee]

Just PM me to order. Prices still same as above.

It is still basically the same as you can see in the latest pictures above. I've been tinkering with a SMD/boxed version, but it will be a while.

The RGB2COMP only has SCART input. This is great for consoles, but if you want to use it with a PC you still have to manage combining H+V sync and buy/hack a VGA-SCART cable together.

With GreenAntz there are both VGA (PC/Pi/PCB etc.) and SCART (console) input versions. VGA version "rolls its own" clean composite sync from your raw PC sync input, then slips it into the Y signal for your TV. This means to connect GreenAntz VGA to a PC, you just need a standard VGA male-male, which are cheap and available everywhere.

GreenAntz is also great for arcade cabs as the PCB legs make it easy to screw into place.

[Kairamiel]

This unit is exactly what i have been searching for! I'm not sure why it's so difficult to find without going through multiple adapters and cables...  I guess those of us who are interested in reaching this far back in technology must not be many. I will send you a PM to purchase if it's still available. Thanks for making this!

[slowready]

Thanks Zebidee, will be PMing you to order 

[Monkeyvoodoo]

Well, I go away for a few years and everything changes. Sending you a PM now Zeb.

[Jamingman]

Wow! I’ll need to snag a few of these.

[apoketo]

Definitely need to upgrade from pal s-video to one of these, but will a boxed version be coming any time soon?

[Zebidee]

Eventually I'd like to make a box, but not a priority. Will make another small batch soon though.

[Zebidee]

GreenAntz v1.9 is out!


I've recently made multiple significant improvements to the GreenAntz design, including:

1) boosted signal levels and greater accuracy
2) crispier, "faster" (transition/skew rates), sharper image
3) brighter, clearer and more consistent colours (more apparent in games with large areas of a single colour)
4) reverse-polarity protection for external power connection
5) cleaner design





GreenAntz is up to version 1.9 now, and will likely my last revision, at least for this retro-styled through-hole design. I think I've squeezed the last drops of good stuff out with this.

The latest v1.9 PCBs (black) have only just arrived, so haven't been able to assemble any yet.

However, I've already built a "limited edition" batch of the GreenAntz v1.9 design onto these racecar-red v1.8 PCBs. They look hot, if a little Christmassy, and red must be faster right? There are minor "cosmetic" differences. Two (unused) holes are somehow misaligned by a fraction of a millimeter. Some components are different to PCB markings. Otherwise exactly the same as v1.9.

The newer GreenAntz v1.9 PCBs are plain black. So order now if you want red.




These are all VGA units but a SCART version is also available.


In other news:


To go with the improved picture output, I've added (re-instated) a switch to optionally activate a sixth-order "Butterworth" 9.5Mhz low-pass filter built into the main amplifier IC. This tidies/smooths the signal and passes SDTV very nicely, but you may lose a whiff of sharpness and comes with an ~800 nanoseconds delay (<1 microsecond, barely noticeable even to most people who worry a lot about latency). Choose your own adventure. If you want to see what 800ns delay looks like on a video signal, switch this off/on and see the picture shift right by up to 1-2mm (depends on screen size).

Contact me if you want to order. For people who have expressed interest recently, i will try to follow-up. I miss you for some reason, please contact me directly anyway.

Will post some more stuff soon about improvements, picture quality and comparisons.

[bobbyb13]

Well now!

Hadn't thought that the version I had could be improved upon really.

Cool to see that you're still at it with this project Andrew.

[Zebidee]

Hadn't thought that the version I had could be improved upon really.

Hmm, how about I send you a free one to compare, discuss, review?

If they are red, surely they go faster... 

[buttersoft]

Gee, if i wasn't broke right now...

I always like to see the updates to this one, your original effort was a great transcoder to begin with, and the extra functionalities to sync have been things i've always wanted in other devices. Another nice job!

[bobbyb13]

An outstanding excuse to build another machine!

Hadn't thought that the version I had could be improved upon really.

Hmm, how about I send you a free one to compare, discuss, review?

If they are red, surely they go faster... 

[Ond]

Cool, put me down for one of the new improved GreenAntz.

[Zebidee]

I've been packing up parcels and sending them to the couriers last few days.

Apologies

For people who ordered the black GreenAntz v1.9 a while ago, I apologise for delays getting them out to you. They are on their way now. There are a few good reasons why I had to delay.

Progress

Firstly, I found that my USB oscilloscope (Owon) had been giving me some wonky readings because it was underpowered. New laptop I was using didn't give it enough juice. I rectified that with a powered USB hub, but it meant I had to re-do measurements and calibrations, especially the video signal output levels.

While I was there I re-visited the colour signal voltage references and also tweaked the regulated voltage up slightly to make a better match. This required some more research, thinking, probing, tinkering and testing. Things made more sense now that the scope had proper power.

Once everything was worked out and bedded down, I needed to update the GreenAntz units I'd already built, and test/calibrate them all again, often going back and repeating earlier steps until I was satisfied.

Further Improvements

Video output is even better again now, especially in terms of colour saturation (brighter, deeper, more accurate and consistent).

Best way to test this is to load up Time Pilot (or similar) and leave it on, let it go through the attract-mode screens (blue-green, green and magenta). Magenta (jets) is the best, as it pushes the video channels the hardest overall (if added together). The background colour should be deep, solid and consistent. No shadows or dark patches. The moving clouds should be bright and prominent, outstanding, not grey and not leaving "shadows". You can test blue by starting a game (the first stage background is a deep blue).

Classic-era games with large areas of solid colour are good for this testing this, such as Wonder Boy and Alex Kidd. You may have another favourite.

Sync Autoswitching - GreenAntz is a bit smarter now - smart enough to not need a switch to select between separate H + V sync VS composite sync input. After letting various ideas roll around in my head for a few days, I had a flash of inspiration    It now auto-detects when there is no vertical sync, and quietly slips into composite sync mode. The coolest part of this upgrade is that it is straightforward, doesn't need any more or new logic gate ICs or PCB changes, uses a single ubiquitous cheap part, and can be implemented on the existing PCBs - even older GreenAntz units.

If you have an older GreenAntz, an urge to solder, and want to upgrade to sync autoswitching yourself, contact me for simple instructions.

Because the GreenAntz v1.9 units I just shipped already have a sync switch (next to VGA jack), I decided to leave it on rather than make a mess removing it. They have been upgraded - just leave it in the "V SYNC" position. Future builds won't have a sync switch.

Thank you all for your patience, it will be rewarded   




Pics! Back in black, sleek, sexy and always in fashion. There will be a few resistors, maybe a cap, soldered on underneath. These reflect the improvements discussed and they are quite solid, safe and secure, especially once the legs are installed.

[bobbyb13]

Fun to watch this evolve in real time!
Looking forward to swapping this latest version into something and getting some pictures/video to look for differences.

[buttersoft]

Nice! looking better than ever!

Sorry to miss the post due to issues i mentioned

[Ond]

I have my new one now. About all I've done is unwrap it and inspect the board close up. I don't know how it performs yet (that's coming) but the PCB work is very clean and pro. I don't even know what those pots do  .  I think it's kind of cool to have access to something very niche like this.  I certainly don't sell anything in the shop like it, just rubbishy vga to composite stuff. I'm not so much a purist as a perfectionist. If I go down the rabbit hole of design getting something to satisfy me goes on and on and Ond.  Good work work Zeb.

[Zebidee]

Nice! looking better than ever!

Sorry to miss the post due to issues i mentioned

I should give a special mention of your composite sync filtering dongle - used it often when doing testing of the composite sync autoswitching. Much more convenient than regenerating and reinstalling video modes via CRT_emudriver.

I have my new one now. About all I've done is unwrap it and inspect the board close up. I don't know how it performs yet (that's coming) but the PCB work is very clean and pro. I don't even know what those pots do  .  I think it's kind of cool to have access to something very niche like this.  I certainly don't sell anything in the shop like it, just rubbishy vga to composite stuff. I'm not so much a purist as a perfectionist. If I go down the rabbit hole of design getting something to satisfy me goes on and on and Ond.  Good work work Zeb.

Fun to watch this evolve in real time!
Looking forward to swapping this latest version into something and getting some pictures/video to look for differences.

Thanks Ond & Bobby, I am really looking forward to seeing your comparisons.

I may be caught in a design rabbit-hole myself - cannot ignore potential improvements. But there is light at the end of this tunnel. Am currently putting together a full-SMD design that, once I am satisfied, can be assembled more easily, or in a factory even. That might be something Ond could sell from his shop! This would be a good point to move on from, then perhaps even make the through-hole designs public.

To me, the main benefit of all this is what I learn and the cool people I get to engage with along the way.

Ond, might be best to leave the pots (luma and Pr) alone if you don't understand them - they are preset/calibrated with an oscilloscope anyway before leaving my lab. If in doubt, the sweet-spot is generally at around 40-45% of total range.

I am sorry to have not responded for a few days. I seriously hurt myself, fell asleep in my chair while pondering the sync, and fell off, bruised my ribs badly (because I landed on an upright scotch bottle which jabbed me hard between the ribs). Movement has been difficult and painful. Feeling a bit better today so braved the keyboard.

GOOD NEWS

The good news is that I'd completed most of that sync work already, and had half-completed a bunch of boards already.

Latest GreenAntz v1.94 includes a little more bling, an LED to indicate that a sync signal is present. It has three states - on means there is proper sync present, off means no sync, faintly lit means only improper sync is present (for example, horizontal but no vertical, or inverted sync). I also tidied-up the sync autoswitching a bit.

Unfortunately there is still no 15khz filtering of the sync signal. To implement this I'd need another logic gate, and can't really implement that with the current PCB.

@Buttersoft, I think I need to investigate using gambaman's programmed PIC for filtering processing sync. I've had a look through the C coding and it seems fairly straightforward. I'd appreciate any advice you have on where to start, especially regarding what ICs to use and how to program them.

Otherwise, I think I could probably achieve similar results with a quad-logic chip.

Here's a pic of the updated GreenAntz v1.94 with sync LED. I'm currently working on a few to fill orders.

Question: does the yellow sync LED look OK? Or should I go with red? I find the yellow looks too much like green, maybe the red would look better. What do you think?

[apoketo]

After using it for a few weeks now, from DOS (200p60) to Indie (270p58) to Video (576i48), powered 24/7: Nothing much to say. It just works, looks like RGB.

The small cardboard box it was sent in was ideal for repurposing into a makeshift housing after adding cable holes.

Great work!

[Daniel B.]

I've sent a PM and want to get one of these bad boys!

I'm not a new member by any means but you had mentioned to make a post, so this is that. Just in case.

[Zebidee]

After using it for a few weeks now, from DOS (200p60) to Indie (270p58) to Video (576i48), powered 24/7: Nothing much to say. It just works, looks like RGB.

The small cardboard box it was sent in was ideal for repurposing into a makeshift housing after adding cable holes.

Great work!

Thanks Apoketo! You are very innovative, using the box like that. I will be working on a proper box soon.

I've sent a PM and want to get one of these bad boys!

I'm not a new member by any means but you had mentioned to make a post, so this is that. Just in case.

I'm currently assembling some v1.94 units with blue sync indicator LEDs, so I will be sure to add extra one for you. Will respond to you directly.

As reported earlier, I had a nasty accident. I'd summarise it as like being punched in the side of the chest by a god wearing knuckledusters. Not sure which god, but then they sure didn't give an F about me. It still hurts. Has softened me up, slowed me down, just a little. Every day gets a little bit better, bit will probably be a couple more weeks until I'm feeling great.

Anyways, production is now on again (to meet backorders first). I will get them out over the next few days.

Here is a quick pic of the GreenAntz v1.94 with sync LED. Promise to get some better pics out soon.

[Daniel B.]

I've sent a PM and want to get one of these bad boys!

I'm not a new member by any means but you had mentioned to make a post, so this is that. Just in case.

I'm currently assembling some v1.94 units with blue sync indicator LEDs, so I will be sure to add extra one for you. Will respond to you directly.

As reported earlier, I had a nasty accident. I'd summarise it as like being punched in the side of the chest by a god wearing knuckledusters. Not sure which god, but then they sure didn't give an F about me. It still hurts. Has softened me up, slowed me down, just a little. Every day gets a little bit better, bit will probably be a couple more weeks until I'm feeling great.

Anyways, production is now on again (to meet backorders first). I will get them out over the next few days.

Here is a quick pic of the GreenAntz v1.94 with sync LED. Promise to get some better pics out soon.

Was this the bottle you fell on? That would be a terrible, terrible thing to experience. At my old age (39) I think I would need a month or 2 to recover, easily. Keep applying the tiger balm/biofreeze/menthol of your choice and try to stretch it out as much as you can, that is one thing that will help. Cold at night, heat in the morning to get them moving if it's worse after rest or prolonged use.

I will work with you in PM, but please sincerely take care ZBD!

[Zebidee]

Was this the bottle you fell on? That would be a terrible, terrible thing to experience. At my old age (39) I think I would need a month or 2 to recover, easily. Keep applying the tiger balm/biofreeze/menthol of your choice and try to stretch it out as much as you can, that is one thing that will help. Cold at night, heat in the morning to get them moving if it's worse after rest or prolonged use.

Yes, you know the type of injury, and yes mornings are the worst. After a couple of hours it isn't too bad. Then, when I get tired, it gets worse again. In addition to stretching etc., I also swim (very gently) every day and get a therapeutic massage every few days.

The really painful aspect of this kind of injury is the muscles cramping to protect the area.

I did something similar to myself about 20 years ago, when I was a bit younger than you are now. Back then I was a real exerciser, six days a week, and I watched Nicolas Cage's "Con Air" with my (then) wife. There's this scene where he's doing handstand pushups and she asked if I could do them. So of course I learned how to do them (foolish me, apparently Nic Cage was cheating in the movie).

So yeah, a couple weeks later I was traveling for work, was late and in a hotel room, but I still wanted some exercise. So I did some handstand pushups, but I was too tired and my legs came down too far on one side. I corrected myself, but too late, the damage was done. I'd crushed the meat between my ribs and partially dislocated them from my spine. Very painful.

This is the exercise I am talking about. Do not do it. The physio treating me kept telling me how dangerous it is, she worried I'd have an aneurysm or something. Never again.

https://www.bigbendsc.com/blog/at-home-exercise-strict-handstand-push-up



It is a more entertaining story than sleeping and falling onto a bottle.