Side Projects: "mini" SLG & CGA->VGA converter

[CraftyMech]

In the process of working on my bartop project, I've started on a couple side projects that will go into my build. I figured I would start a separate project thread for these projects, and keep it updated as I make progress.

Project #1 - mini SLG (scanline generator)

The mini SLG is an inexpensive, and compact scanline generator that is compatible with any device that outputs a standard VGA signal @ 640x480 & 1024x768 resolutions.

Compatible devices include:

-- a PC video card
-- a multigame pcb with VGA output, such as a 60-in-1 board.
-- a CGA->VGA converter board, such as the GBS-8200

For best results, the VGA source should be set @ 640x480 resolution.

Below is a photo of the finished product (color choices are black, beige, and shiny metalized plastic), and some example photos of the mini SLG is action.

mini SLG in a black shell


Pac-Man (60-in-1 board) on an LCD @ 640x480


Fatal Fury 2 (Neo Geo MVS board) on a CRT @ 640x480 using a GBS-8200 CGA->VGA converter

[CraftyMech]

Project #2 - CGA->VGA converter

I've been experimenting with the GBS-8200 CGA->VGA upscaler, and have not been that impressed with the standard CGA resolution conversion. So I've started building my own board dedicated to taking low-medium res CGA games to VGA @ 640x480. I'd rather build a board that does that one function really well, then fuss with an import board that has inconsistent quality, but converts a wider range of resolutions.

My upscaler design has three main stages: CGA in (ADC), data buffers, and VGA out (DAC). I've just about got the VGA signal generation worked out, so next step will be to look at building the ADC modules for the CGA in stage.

This project could be quite a journey, I'll post updates as I make progress.

[Yvan256]

Which ICs are used in each project?

[CraftyMech]

The mini SLG is built around a Dual D-Type Flip Flop, which is also used in the SLG-3000, T-SLG and RetroVGA projects. However, those projects use an additional IC, a Quad Tri-State Bus Buffer. I found that the Bus Buffer was not needed with a few changes to the circuit layout. Removing the Buffer IC simplifies the circuit, but sacrifices the ability to change scanline widths as both Flip Flops are already in use.

For the CGA->VGA converter I've been working on the VGA out stage, and right now I'm using an ATMega microcontroller, and coding in assembly for accurate signal timing. For the ADC I'm looking at chips in the 5-8Mhz sampling range, and for the DAC I think I could get away with a R2R ladder).

The schematic has been removed temporarily due to a color balance issue (green tint) with certain PC video cards. Once the solution is worked out, I'll update the schematic.

[Le Chuck]

I don't understand all your fancy talk but if this is a magic dongle to add scan lines without software I want one!

[Yvan256]

The mini SLG is built around a Dual D-Type Flip Flop, which is also used in the SLG-3000, T-SLG and RetroVGA projects. However, those projects use an additional IC, a Quad Tri-State Bus Buffer. I found that the Bus Buffer was not needed with a few changes to the circuit layout. Removing the Buffer IC simplifies the circuit, but sacrifices the ability to change scanline widths as both Flip Flops are already in use.

The schematic is below. Pin 14 (VCC) on the Flip Flop is left floating, and I'll post up a bit more detail about why tomorrow.

So you're telling me you're doing all this with plain old logic ICs? 

For the CGA->VGA converter I've been working on the VGA out stage, and right now I'm using an ATMega microcontroller, and coding in assembly for accurate signal timing. For the ADC I'm looking at chips in the 5-8Mhz sampling range, and for the DAC I think I could get away with a R2R ladder (CGA is only 6bit color if I remember).

That would be funny if it were the ATmega328 because at the moment that little guy is helping me testing stepper motors for my CNC machines. Except I don't use assembly, C is plenty enough for my needs. 

[CraftyMech]

I don't understand all your fancy talk but if this is a magic dongle to add scan lines without software I want one!

It sure is! There have been other projects before mine that have implemented scan lines in hardware (SLG-3000 & T-SLG) and I got my inspiration from those designs. That said, I believe this design is the most compact so far, and the first to be squeezed into a "dongle" size adapter. I wanted to come up with something that was convenient for cramped spaces (like inside my bartop project) and fit into a ready made plastic shell so it wasn't just a circuit board (enclosures can be added to the other projects I mentioned, but that just adds to their bulk).

[Le Chuck]

I don't understand all your fancy talk but if this is a magic dongle to add scan lines without software I want one!

It sure is! There have been other projects before mine that have implemented scan lines in hardware (SLG-3000 & T-SLG) and I got my inspiration from those designs. That said, I believe this design is the most compact so far, and the first to be squeezed into a "dongle" size adapter. I wanted to come up with something that was convenient for cramped spaces (like inside my bartop project) and fit into a ready made plastic shell so it wasn't just a circuit board (enclosures can be added to the other projects I mentioned, but that just adds to their bulk).

Right-o so... how much with shipping to Phenix City AL?  I want to throw this bad boy in my bartop and see how it works.  If you don't want to sell post an instructable.  Oh, and when in vertical mode the scan lines would be horizontal I take it?   

[CraftyMech]

Right-o so... how much with shipping to Phenix City AL?  I want to throw this bad boy in my bartop and see how it works.  If you don't want to sell post an instructable.  Oh, and when in vertical mode the scan lines would be horizontal I take it?

The scanlines would actually be vertical for a monitor in the vertical position (they are horizontal for a monitor in the normal upright position). What kind of monitor do you have in your bartop? I've got a deal for you, I only have two monitors to test on so I could use a couple beta testers. I have not put in an order yet to fabricate the pcbs (more like postage stamps as small as they are), but I can whip up another prototype (like the one pictured) and send it to you to try out. If you like how it works then hold onto it and we can just consider it a barter in exchange for your feedback. The difference between the prototype and the finished board is just that I hand wire my prototypes versus having the traces on the underside (the lines you see on the bottom of circuit boards). The performance is exactly the same, it just takes longer to do by hand so I would have boards fabricated before I started actually selling these. PM your address if that sounds cool and I'll get one built and shipped out to you. PS - What kind of hardware are you running in your bartop? 60-in-1 type board, dedicated game board, or PC hardware?

[Nephasth]

If you need another beta tester, I'm down. Plenty of different types of monitors I can test on. Have a 60-in-1, PC setups, and original arcade pcbs I can run through my CGA converter.

[CraftyMech]

So you're telling me you're doing all this with plain old logic ICs? 

That would be funny if it were the ATmega328 because at the moment that little guy is helping me testing stepper motors for my CNC machines. Except I don't use assembly, C is plenty enough for my needs. 

Actually I am using an ATMega328 @ 20mhz for my cga->vga converter! The ATmega line of chips are really nice, inexpensive and easy to use. There is a lot of "arduino" stuff out there, but those are just dev boards and some extra code libraries built around the ATmega series of chips. So there are a lot of ATmega projects out there that you can find source code for, and help you figure out how to make things work for your own projects. Funny you mention stepper motors, I've written drivers in C for unipolar stepper motors for the ATmega, and been meaning to get around to working out how to use PWM to implement micro stepping on a stepper motor for a 3d printer project I've been tinkering with.

Yep, just a basic digital logic IC. The HSync signal pulses at the start of every horizontal line on the screen, and when that happens the Flip Flop toggles between "0" and "1" (or vice versa). When the output is "0", the RGB signal is rerouted (connected to ground) and the result is a scanline on the screen. The fun thing about circuits like this one is that back in the late 70s/early 80s arcade boards were stuffed with logic gate ICs (hence the giant Centipede board) and all that arcade magic happened the "hard way" by today's standards. Today, you have a square surface mount IC that implements thousands of logic gates (FPGA), and they are programmed in a hardware description language, instead of designing a circuit that integrates all the input/outputs of the various chips.

[CraftyMech]

If you need another beta tester, I'm down. Plenty of different types of monitors I can test on. Have a 60-in-1, PC setups, and original arcade pcbs I can run through my CGA converter.

Awesome Nephasth, PM your address to me and I'll get a prototype built and shipped out to you.

I think 2 beta testers will work for now. I should have a good idea by Monday when I will be able to start selling the finished product (probably late December).

[emphatic]

Very excited to hear about your CGA->VGA gizmo. And thoroughly impressed.

[opt2not]

  Aye, same here...will be eagerly following this thread for sure.

[DaOld Man]

Impressive!!

[emphatic]

  Aye, same here...will be eagerly following this thread for sure.

Hey, who're you're callin' stupid?   

[CraftyMech]

Thanks guys, I'll be sure to post updates as I make progress. My motivation for starting the project was the lack of options for arcade cga -> vga conversion. The GBS-8200 works ok, but I believe the board is doing full frame conversion in order to handle the various output resolutions, and that is where the visual artifacts are coming from. My plan is to do a line buffered conversion, which buffers the CGA signal two lines at a time, and upscales the data for 640x480 VGA output, resulting in a cleaner conversion with less artifacts.

I've been building the two prototypes of the mini-SLG scanline generator this weekend, looking  forward to getting some feedback from my beta testers on different setups.

[emphatic]

My plan is to do a line buffered conversion, which buffers the CGA signal two lines at a time, and upscales the data for 640x480 VGA output, resulting in a cleaner conversion with less artifacts.

The trade-off is increased lag though, right?

[CraftyMech]

The problem that has to be solved with CGA->VGA conversion is that the VGA signal is at least twice as fast as its CGA input (31k vs. 15k). So some sort of signal buffering has to take place, either two vertical lines at a time, or worst case two full frames at a time (480x2 lines).

So the lag calculations for best & worst cases would be:

Given 2 buffered lines of CGA signal, the signal lag would be at least 60 microseconds (30 microseconds per line @ 15k).

For 2 buffered frames of CGA signal, multiply 30x480x2= ~28 milliseconds.

28 milliseconds isn't terrible for full frame, but even with a CRT that amount of lag might cause problems for precise patterns in a game like Pacman. Throw a LCD into the mix and the lag starts getting a little ugly though.

UPDATE: I poked around the GBS board, and sure enough I found a 8MB SDRAM (S6432AFTA-6B-E) chip with burst read/write. With that size of video memory, I'm feeling confident now that the GBS uses some flavor of full frame conversion, and therefor a display lag of between 14-28 milliseconds for CGA->VGA.

[CraftyMech]

The new prototype version of the mini-SLG is a tight fit! A printed board will definitely free up some space as all the hookup wire will be replaced with traces on the board underside.

Second photo is a 256 color palette test from the VGA out side of my CGA->VGA converter project. I went with the standard VGA RRRGGGBB convention, which gives 8x8x6 for 256 colors. The DAC turned out to be really simple, with 8 resistors. Right now I'm using 5% resistors, but I'll change that out for 1% in the near future for better accuracy.

I realized when working on DAC, that I don't need an 8-bit ADC per channel. I only need two 3-bit ADCs for Red,Green and a 2-bit ADC for blue. So with that in mind I'm going to see if I can't use a R2R ladder & a couple transistors to build the ADC module, instead of specialized IC chips. If I can get that to work well with good results, then I'll be able to cut a good chunk out of the parts budget.

[Unstupid]

If you can make these work as good as the SLG3000 then I'd buy some from you... I hate sending my $ to germany!  Plus shipping takes forever!

[CraftyMech]

If you can make these work as good as the SLG3000 then I'd buy some from you... I hate sending my $ to germany!  Plus shipping takes forever!

Exactly why I decided to build my own, I didn't want to deal with international shipping!

The SLG-3000 has more features, but I think the mini-SLG works great for standard/medium resolutions in a compact package. I have a couple prototype units that I mailed to two of our fellow forum members, and I'm looking forward to the feedback. The next step would be to get pcbs made, and I would be ready to offer up units for sale. With Christmas rapidly approaching, it is looking early January when the mini-SLG would be available.

What kind of setups would you be looking to use the mini-SLG in?

[Unstupid]

If you can make these work as good as the SLG3000 then I'd buy some from you... I hate sending my $ to germany!  Plus shipping takes forever!

What kind of setups would you be looking to use the mini-SLG in?

Looking to build a whole bunch of these, in different configurations...  10" screens that run at 640x480.  Want to make a whole arcade of little machines running classic games:

[yotsuya]

I'd be in for a couple, depending on price. At least one for sure.

[Unstupid]

If funding is an issue maybe throw it up on kickstarter 

[Jumpman64]

I'd be in for one or two as well.

[Fudoh]

CraftyMech,

that's fantastic news about your CGA to VGA converter project ! In all honesty - a community based 15 to 31khz converter board is what I've been waiting for since ages. I'm running http://retrogaming.hazard-city.de/ which you might know and I've been through all the available converter solutions.

I'd very much like to offer you any assistance I can, any promotion and a full featured preview or review on my page. If you need any input, also please don't hesitate to ask !

I can't see any way to contact you other than here, but feel free to drop me an email or contact me otherwise! Would be great to get in touch with you !

Tobias / Fudoh

[johnm]

Did you just join from shmups forum?

[Fudoh]

I sure did, yes!

[johnm]

Glad my link helped you

There's a monitor/tv section here i'm sure you'll love.

[bootsector]

I'm really liking of what I see here! Looking forward on news about VGA signal converting! 

[CraftyMech]

Thanks everyone for the interest in the mini-SLG and CGA->VGA converter! I'll be finalizing the mini-SLG design by early next week, and will order the printed circuit boards. Based on the interest level I'm seeing in this thread, I'm shooting for an initial run of around 20-30 units. Once I know the parts cost I'll post the price, I'm shooting for around $15.

that's fantastic news about your CGA to VGA converter project ! In all honesty - a community based 15 to 31khz converter board is what I've been waiting for since ages. I'm running http://retrogaming.hazard-city.de/ which you might know and I've been through all the available converter solutions.

Hey Tobias, I took a look at your website and you really have a lot of great information there on a ton of converter products. I'm going to have to set aside an hour just to read through the reviews. I'm sure I'll have some questions that I can pick your brain about, I'll send you a PM with my email address.

[sharpfork]

$15 would be a nice price point.
I have one of bootsector's SLGs (which I really like) so I'm not currently in the market for one.  I always like to know what options are out there for future builds so I'll keep an eye on this thread.

SIII + Cyanogen + Tapatalk 2

[yotsuya]

At a price point of $15, I'd be in for three. Thanks for doing this.

[Yvan256]

Looking to build a whole bunch of these, in different configurations...  10" screens that run at 640x480.  Want to make a whole arcade of little machines running classic games:

You have a source for 640x480, 10" screens? Where? How many left? Which input(s) do they have? How much are they?

[Unstupid]

You have a source for 640x480, 10" screens? Where? How many left? Which input(s) do they have? How much are they?

Don't want to derail this thread so I replied on my thread over here: http://forum.arcadecontrols.com/index.php/topic,128428.0.html

BTW if you make the slg available for $15 I'm in for at least 10.

[Nephasth]

The mini-SLG is a pretty neat little device. Haven't messed with it a whole lot yet, but so far I like it. Here's MAME on a 19" HP LCD at 1024x768...

                                                            BEFORE


                                                             AFTER


I'd say this is a definite must have for any cab with an LCD (60-in-1s 'n such).

I fiddled with the pot, but didn't notice any difference. However, the mini-SLG was on the back of my computer under my desk. I'll have to dig out another VGA cable so I can adjust the pot while watching the monitor.

Great work CraftyMech!


EDIT: Pics fixed. After seeing this difference, I need to make a dedicated vertical cab...

Here's what scan lines look like the wrong way vs. the right way...

[RRR]

That's awesome, and great price too.

@ Nephasth: Could you post a pic of it running at 640X480?

[CraftyMech]

Thanks for posting up the pictures Nephasth! I did not do that much testing at 1024x768, so I'm glad to hear you liked the results with a vertically orientated monitor.

When you get a chance, check out the mini-SLG for your 60-in-1 board. One thing I tried to do with my design was to not use straight black scanlines. I felt that on the low-res games (Pac-man, etc..) the detail suffered and felt even lower res. So I kept the scanlines at around 15% intensity and found that the scanline impression was still quite nice, while not degrading the game resolution. Let me know what you think!

As for the pot adjustment, it controls the intensity of scanlines for the Red channel, versus the Blue channel. The effect will be more pronounced on low-res games, at 640x480. I've actually been thinking about dropping the pot from the design. As you discovered, it is hard to judge unless you are looking right at the monitor, and the effect is more pronounced on low-res games, and not so much at higher resolutions. Plus I do like the idea of the mini-SLG as a true plug-and-play adapter, with no switches or adjustments to worry about. Instead, I would use a fixed resistor to strike a good balance between the R,B signals.
 

[Nephasth]

Looks great with a 60-in-1! It's really hard for me to capture good pics, but it looks much better in person. Not sure exactly what the resolution is that the board puts out, but it's lower than 1024x768. These were on a 15" Samsung.

No mini-SLG:


mini-SLG (this one did a good job of showing th scanlines on the fading power pellet):


Galaga ship - no mini-SLG:


With mini-SLG:


Quick shot of the enemies (the top row showed up best in the pic):


Thoroughly impressed CraftyMech!

Have you tested it with a Gnobes converter yet?

Oh yeah, I was able to adjust the pot while watching the screen with the 60-in-1. I'd say keep the feature. I was able to find a preference with it.

[yotsuya]

Just let me know when you're ready to take my money, CM! 

[CraftyMech]

Thanks Nephasth for posting up pictures of the 60-in-1 + mini-SLG!

The 60-in-1 puts out 640x480, which is perfect for the mini-SLG to work with. I have tested as well with the GBS-8200 CGA->VGA converter and the SLG worked great. I tried it out using a Namco Pacman/Galaga board.

As for the quality of the GBS-8200 itself, well that is another story I'm making progress though on my own CGA->VGA converter, and will be building scanline generation into the board, toggled on/off through an on-screen settings menu.

Just let me know when you're ready to take my money, CM!

Soon! Today I spent some quality time laying out the pcb, and fitting a large batch on a 7"x7" panel (50 units per board). I'll be putting the order through tomorrow, and with luck I'll get the boards back right before Christmas. My component/connector orders are also starting to come in, so I should have everything I need to start building the production units before New Years, and that puts me on track to start selling the first week of January. I'll keep everyone posted with some pics of all the parts piles once they arrive.

[Le Chuck]

I received my unit for testing earlier this week but wasn't able to do any testing until this evening.  This is an impressive little tool.  The integration is pretty much seamless.  My unit was missing the screw posts to secure the adapter to the monitor but being a test unit this isn't an issue.  Bottom line, it works and works well. 

Monitor used for this test: M170EN05 LCD, 17" AUO SXGA Max Resolution 1280x1024
Resolution used in this test:  480x640
MAME was paused for pics, shading on pause is 10%.

 
Galaga left to right (or top to bottom depending on which device you're reading the forums on) we've got no scan gen, scan gen red full up, scan gen middle, scan gen red full down. 


Same deal, no scan, red up, half, red down


I really didn't like the green too much so I turned the red full up and left it, just looked "more right" to my eye but YMMV.  The pot isn't a bad idea and I do notice a huge difference but I think that if you just went with a strong red and ditched the pot I wouldn't mind at all.  Dodonpachi shown without and with.  The scan gen really takes the edge off and gives the bullets a nice warm glow rather than being little pink squares. 

 
I played around with some horizontal games as well.  It does take the edge off and adds a richness to the background.  This is a great project and is heading in the right direction.  Crafty, you've got a real winner here.  I'll get it tried out on some other platforms but for right now I'm just having a blast playing and almost immediately forget it's there until I disconnect it and then I immediately miss it.

One thing that I did notice right away, my MALA skin looks like hot garbage with scan lines.  This is not an issue with the scan gen at all, just a result of designing the art based on how it would look on the stock monitor.  If you have an eye for that kind of thing and are building with one of these in mind you're going to want to design your layouts/skins/whatever to capitalize on the new presentation you'll be getting out of the monitor with this scan gen.  Makes me want build a dedicated vert cab.

[CraftyMech]

Thanks Le Chuck for posting up these photos!

I've been thinking about the trim pot and I agree with you that I think using a fixed resistor to give that setting a balance that is biased to Red would be a good compromise. The part is actually the most expensive component, and it is a bit of a pain to get it to fit in the plastic case and get the case to fit together right.

So although I'm one of those people that loves tinkering with adjustments to get exactly what I want visually, I think that by removing the pot the unit becomes 100% self contained, and truly plug & play, which is also a nice feature. Color balance can always be adjusted using the monitor controls as well.

One trick you can use with Mame skins, or other emulator menus is to run them at 800x600, or 1200x1024. Those are +vsync modes, so the mini SLG will just pass the signal through without adding scanlines.

Sorry I forgot to include the screw posts! The shells came with a set for each end but because I was plugging and unplugging the adapter so much during my testing I never installed them in the prototypes.

[Eldritch1969]

Hi,
Added a link to your project in the Scanlines Generators topic at Bartopmania.com.

Keep up the good work, CraftyMech

[CraftyMech]

Thanks Eldritch, I'll have to take a look at bartopmainia.com

Today I replaced the trimpot with a fixed resistor chosen to create a nice balance for the intensity of the RGB scanlines. I like how the result looks for the games I've tested. I used a Namco MsPacman/Galaga board, and my 60-in-1. More pictures to follow, but I think I've arrived at the final design! Removing the pot saves me $ and assembly time, and will allow me to sell the mini SLG at $15 like I've mentioned before. I like how the design is now a true plug-and-play adapter, just plug it up between your monitor and video source, and you have scanlines

Ms.Pacman (60-in-1 board) & mini SLG on a LCD (640x480):


Congo Bongo (60-in-1 board) & mini SLG + GBS-8200 CGA->VGA converter on a CRT (640x480):


Fatal Fury 2 (Neo Geo MVS board) & mini SLG + GBS-8200 on an LCD (640x480):


Fatal Fury 2 & mini SLG + GBS-8200 on a CRT (640x480):


1943 Kai (60-in-1 board) +mini SLG on a CRT (640x480):

[Nephasth]

Looks great!

[yotsuya]

Can't wait! Definitely in for three!

[emphatic]

Looks great!

It does indeed!

[CraftyMech]

Today I received an early Christmas present, the PCBs I ordered for mini SLG production!

To keep the per board fabrication cost low, I squeezed 50 copies of the design onto a 7" x 7" panel. I had to buy 4 boards however to qualify for the discount package, so lets just say I won't run out of stock for quite awhile

I scored and separated a row of boards tonight, and built and tested my first production unit. Worked like a charm!

The first picture below is one of the 7x7 panels, and the second picture is of mini SLG #1 in a black case. I will have two colors available for the plastic shell: beige & black. I also have a smaller quantity of the metalized plastic shell on the right.

I'll get a price list for single and multiple discounts posted this weekend, and I'll be ready to start building and shipping out units late next week!

[sharpfork]

If I order one, can we schedule a 1up or 2up delivery?

[CraftyMech]

Sounds like a plan, I have not been to a good arcade in forever. And I will accept payment in the form of beer

[Nephasth]

200 mini-SLGs!

[Eldritch1969]

Could I order two of these, please ?

[RigoHoward]

Today I replaced the trimpot with a fixed resistor chosen to create a nice balance for the intensity of the RGB scanlines.

Just wow! it's impressive!

I really respect your work and i want to thank youre sharing the schematic with all of us

I got one question (trying to do a mini SLG by myself), i can figure out what kind of resistor do you use to balance the intensity scanlines neither betwen wich pins it's placed. Can you give me a hint?

Thank you in advance!

[CraftyMech]

Hey Rigo,

In the schematic, the Red signal line is connected to the 100 ohm R4 resistor, and is connected to pin 5 of the IC. The blue signal line is connected to the 1K ohm R3 resistor, and is connected to pin 6. Both resistors are the common carbon film type, 1/4 watt.

[CraftyMech]

Could I order two of these, please ?

You bet Eldritch! I'm working this afternoon on figuring out the shipping cost to Europe. The mini is very light weight, so the shipping should be quite reasonable. I'll send you a PM once I have the numbers worked out.

[yotsuya]

Yay! 

[CraftyMech]

I started this project because I wanted inexpensive scanlines for my bartop build. Once I realized the design would be simple and very compact, I decided to offer the mini for sale because I believe an SLG is a must for retro gaming on VGA displays. My margin on each unit is low, so I'm not going to get rich selling these. If I can sell enough units to cover my investment in parts & time, plus a little pocket change, I'll be happy

The price list + shipping costs are below, just send me a PM with your order & email address and I will send you a PayPal invoice (for the time being, I will only be accepting PayPal for payment). I will start shipping orders next Friday!

mini SLG - $15 USD + shipping

Shipping: $3 USA, $4 Canada, $9 Europe (other destinations may cost more/less)


Deals For multiple units (US/Canada shipping included,  +$6 Europe):

"Duo" - 2 mini SLGs for $30 (save $3)

"Trio" - 3 mini SLGs for $42 (save $6)

If you are interested in more than 3 units just let me know in a PM and we can work out a deal.

Color choices for the plastic shell are beige & black. I have a limited quantity of shiny metalized plastic shells for $2 extra per unit (see photo a few posts back).

If for any reason you are not satisfied, I'll accept a return if you send a PM within two weeks of delivery (for the entire order, no partial returns). If you pay for return postage, I'll refund your entire purchase price (including original shipping costs) once I receive the unit(s) back.

If you have any questions, just ask. 

Scanlines for everyone!

[RigoHoward]

Hey Rigo,

In the schematic, the Red signal line is connected to the 100 ohm R4 resistor, and is connected to pin 5 of the IC. The blue signal line is connected to the 1K ohm R3 resistor, and is connected to pin 6. Both resistors are the common carbon film type, 1/4 watt.

Wow that was very detailed, many thanks!

Actually the problem was i was looking your old schematic..

I didnt realize that you updated the image

[bootsector]

Great work on making this a very accessible and affordable piece of hardware!

But what I like most is that you kept the open hardware spirit by making available the schematics.

You, Sir, got all my respect!

Cheers,

bootsector

Sent from my Nexus One using Tapatalk 2

[CraftyMech]

Wow that was very detailed, many thanks!

Actually the problem was i was looking your old schematic:

No problem Rigo! Although to avoid confusion, can you remove the old schematic from your post? Thanks!

Great work on making this a very accessible and affordable piece of hardware!

But what I like most is that you kept the open hardware spirit by making available the schematics.

You, Sir, got all my respect!

Thanks Bootsector! The projects that yourself and Toodles developed (RetroVGA & T-SLG respectively) over at the shoryuken.com forum inspired me to design the mini SLG. So you deserve credit for leading the way!

[RigoHoward]

Wow that was very detailed, many thanks!

Actually the problem was i was looking your old schematic:

No problem Rigo! Although to avoid confusion, can you remove the old schematic from your post? Thanks!

Fixed!

Thanks again, sadly i suck with this kinjd of projects , i already do all the wiring use the resistors and doesnt work for me

I check my soldering twice and even measure continuity using a multimeter but not luck yet

edit: i got video signal now after disconnecting HDMI cable (my bad...), but i dont get any scanlines i just have a ghostly image :S



BTW, how much it cost shipping two of your mini SLG to Chile?

[yotsuya]

Payment sent for 3! Thanks again!

[CraftyMech]

edit: i got video signal now after disconnecting HDMI cable (my bad...), but i dont get any scanlines i just have a ghostly image :S

It sounds like the output pins on the 74 IC are being held low. Double check that pins 2 & 6 are tied together, as well as pins 8 & 12. Those connections cause the Flip Flop to toggle with every vertical line. Also double check that vsync is connected to pin 1 & 13, and the HSync line is connected to pin 3. The Flip Flop won't toggle correctly without those connections either.

And shipping to Chile would be $9 USD, so just send me a PM with your email if you decide to order, I will start shipping next Friday

[Yvan256]

Not sure if it has been mentioned or asked, but what about offering your mini-SLG in kit form or even PCB only?

[CraftyMech]

Not sure if it has been mentioned or asked, but what about offering your mini-SLG in kit form or even PCB only?

My margin is low enough that there is not really an incentive for me to sell them as a kit. There are also a number of connections that have to be made between the VGA connectors and the pcb, so I can imagine a lot of troubleshooting on my end helping diagnose mistakes in wiring.

[Almighty]

Hello,

Looks awesome and let me know when they are ready
I really like to try one by myself for my new bartop build soon with a 60-1 pcb board.

Cheers

[CraftyMech]

Hey Almighty,

The mini SLG is ready to ship! A couple posts back is the price list, and also here in the buy/sell/trade forum: http://forum.arcadecontrols.com/index.php/topic,129344.0.html

PS - The mini SLG works great for 60-in-1 boards, I have one myself and used that board as my test system quite a bit while developing the design.

Just send me a PM with your email and order, and I'll send you a PayPal invoice.

[Almighty]

hello CraftyMech,

send you a pm for one mini slg

cheers!

[BadMouth]

I have a few oddball questions. 

Would it be possible to make a simple circuit that could turn the scanlines on and off on the fly (without bypassing the whole thing)?

What happens when it gets a widescreen resolution like 1280x720 passed to it?

[griffindodd]

PM sent, this will be the perfect addition to my little bartop cocktail.

[CraftyMech]

I have a few oddball questions. 

Would it be possible to make a simple circuit that could turn the scanlines on and off on the fly (without bypassing the whole thing)?

What happens when it gets a widescreen resolution like 1280x720 passed to it?

I was originally planning an on/off switch, but decided to not include one so I could keep the parts cost low & shave some time off of assembly. It is also a tight fit for the circuit board inside the shell, and it would be challenging to consistently mount a switch so that the case would snap close correctly.

For resolutions other than 640x480 or 1024x768, if the mini SLG is not compatible (the device requires a -vsync signal to work properly) then the screen will display normally without scanlines.

[ckong]

I got mine today. They are so tiny and sweet 



I suppose that they are meant to come without the screws?

[CraftyMech]

Hey CKong, great that your package arrived! Let me know how they work out for your setups.

The plastic cases I am using did come with screws, but they are tough to work with without a tiny screwdriver (not thumbscrews).  The cases were meant for VGA gender changers, so they were also just two sets of screws, rather then screws for one side, and posts for the other. The final straw was that they screws had to be in place when I snapped the plastic case shut, they have a lip on them that keeps them in place, but also prevents installing them once the case is shut. So I decided it was more trouble then it was worth for myself when building the units, and for the user because they were awkwardly small, and not hand adjustable.

[sharpfork]

I decided it was more trouble then it was worth for myself when building the units, and for the user because they were awkwardly small, and not hand adjustable.

Sounds reasonable.

[PL1]

CraftyMech -- For those that might want to find thumbscrews, what is the manufacturer/part number for the case you used?


Scott

[CraftyMech]

The screw holes are actually not threaded, so to install thumbscrews would require opening the case, and that is very tricky to do without damaging it. I've thought about sourcing a better case down the line if the unit continues to sell.

On a different subject, work continues on my CGA->VGA conversion board. I've been making good progress and have been able to drive a fairly stable image off a Neo Go MVS board, although more tweaking of the signal timing is needed. Once I have a nice conversion to demonstrate, I'll post up a YouTube video link of the converter in action.

The ADC module is still fairly primitive and just for prototyping, with 2bits per channel (6bit color). That works great for Pacman, but not so much for Neo Geo titles running on 16bit color. So I am experimenting with an 8bit ADC chip that if used one per channel would give a color depth of 24bits. The downside is it is SMD, so prototyping is a pain and requires soldering the chip to a small pcb that has through-hole pins and will plug into a breadboard. That is one bummer about the SMD revolution, a lot highly specalized integrated circuits, like ADC modules, are not available in DIP packages anymore. The ADCs that are available in DIPs tend to be under < 5mhz, which is too slow even for the 6-7 MHz pixel clocks of CGA "standard resolution" hardware.

[Yvan256]

Maybe not a good idea for the final versions, but it could help with prototyping...
https://www.sparkfun.com/search/results?term=soic+dip+adapter&what=products

[Le Chuck]

I'm using wee zip ties through the thumb screw holes to secure to my monitor and cable in the absence of thumb screws.  Seems to be working well but if I need to take it off for any reason I have to use a pair of snips.  Very secure. 

[joeH]

I have a few oddball questions. 

Would it be possible to make a simple circuit that could turn the scanlines on and off on the fly (without bypassing the whole thing)?

What happens when it gets a widescreen resolution like 1280x720 passed to it?

I was originally planning an on/off switch, but decided to not include one so I could keep the parts cost low & shave some time off of assembly. It is also a tight fit for the circuit board inside the shell, and it would be challenging to consistently mount a switch so that the case would snap close correctly.

For resolutions other than 640x480 or 1024x768, if the mini SLG is not compatible (the device requires a -vsync signal to work properly) then the screen will display normally without scanlines.

So, can the unit basically switch on its own depending on what resolution a PC is sending to the monitor? 

I use a 24" LCD to fool around with MAME and other emulators.  However, the same monitor is also used for my home server.  I'm assuming from what you are saying that when the PC sends a native 1920x1200 signal, the SLG won't work.  But if I start up an emulator, say MAME for example, and set the config for MAME to start up a game at 640x480, it will work?  That way the scanlines only appear when emulation is started? 

Or did I read that wrong? 

Also, will the SLG still work with an HDMI to VGA adapter?

[CraftyMech]

Since this is the projects thread, I'll give a bit more detail about why the mini SLG does not work on VGA resolutions greater than 1024x768.

The design of the mini requires a VGA signal with a -vsync. VGA modes have a + or - vertical sync signal depending on the resolution. Generally, all the resolutions above 1024x768 have a +vsync. This works out fine for the mini SLG as scanlines don't tend to look very good at high resolutions due to banding effects caused by upscaling internally by an LCD to bring an input resolution to the native resolution of the monitor (unlike the older CRTs, LCDs have "pixels" of finite size).

So if the mini encounters a +vsync signal, the VGA signal simply passes through the device and the image displays normally on the monitor. A -vsync signal activates the circuitry and scanlines are added to the image.

[secret80sman]

I am worried about the unit damaging the pins on my video card since there are no thumb screws. Would it be better to connect a male/female cable to the computer, the connect the mini SLG and then the monitor to the SLG?

Or do you offer other larger cased options with thumb screws. I would pay more money so that is no prob if available.

[CraftyMech]

I have the screws that came with the case, and I can throw them in the package with the mini SLG on request. They pop into place in the case with a little push. However they are not thumbscrews and will require a small screwdriver (or really tiny fingers) to screw into place. I wouldn't recommend putting another cable in the chain between the computer and monitor, you want to install the unit preferably connected directly to your video card.

[Yvan256]

And now for the one million dollars question: does the miniSLG work with a PSOne LCD display that has been modded for VGA?

[secret80sman]

I have the screws that came with the case, and I can throw them in the package with the mini SLG on request. They pop into place in the case with a little push. However they are not thumbscrews and will require a small screwdriver (or really tiny fingers) to screw into place. I wouldn't recommend putting another cable in the chain between the computer and monitor, you want to install the unit preferably connected directly to your video card.

Ok, sign me up and include the screws please. What is the latest order method?

[chopperthedog]

Ok, sign me up and include the screws please. What is the latest order method?

http://forum.arcadecontrols.com/index.php/topic,129344.0.html


good day.

[Furry131]

congrats on winning the UCA's.         http://forum.arcadecontrols.com/index.php/topic,130500.0/topicseen.html

speach!!!!

[Richie_jones]

Recieved thank you. Very pleased

[CraftyMech]

Great to hear Richie!

Thanks Furry!

Four score and seven years ago...

[Richie_jones]

Cheers I thought you'd sent me 100 given the size of the box!!!!!

[secret80sman]

Thanks Crafty. Got the unit days ago and the scan lines look good without taxing my CPU by running them in software as before. Do I have to get used to the hard to read text now on the list of games in Mameui since the effect is applied to the desktop as well or is there a workaround for that? Bumped font size up a bit and that helped somewhat.

I suppose using a graphical from end would eliminate that issue too. Great little unit.

[Richie_jones]

Thanks Crafty. Got the unit days ago and the scan lines look good without taxing my CPU by running them in software as before. Do I have to get used to the hard to read text now on the list of games in Mameui since the effect is applied to the desktop as well or is there a workaround for that? Bumped font size up a bit and that helped somewhat.

I suppose using a graphical from end would eliminate that issue too. Great little unit.

I'm sure crafty will chime in, but if you have your front end at a different resolution other than the one the slg uses then you won't get scan lines, my hyperspin is 1280x1024....
Not tried mine yet but I think this is the way around it...

[CraftyMech]

Cheers I thought you'd sent me 100 given the size of the box!!!!!

Yep! For overseas shipments I like a box with extra room for whatever punishment the postman inflicts on it

Thanks Crafty. Got the unit days ago and the scan lines look good without taxing my CPU by running them in software as before. Do I have to get used to the hard to read text now on the list of games in Mameui since the effect is applied to the desktop as well or is there a workaround for that? Bumped font size up a bit and that helped somewhat.

I suppose using a graphical from end would eliminate that issue too. Great little unit.

Richie had the right idea, running your front end at 1280x1024 will give you a normal display, and then run your games at one of the supported resolutions (640x480 or 1024x768) for scanlines. Let me know how that works out for you!

[secret80sman]

Thanks Crafty. Got the unit days ago and the scan lines look good without taxing my CPU by running them in software as before. Do I have to get used to the hard to read text now on the list of games in Mameui since the effect is applied to the desktop as well or is there a workaround for that? Bumped font size up a bit and that helped somewhat.

I suppose using a graphical from end would eliminate that issue too. Great little unit.

Richie had the right idea, running your front end at 1280x1024 will give you a normal display, and then run your games at one of the supported resolutions (640x480 or 1024x768) for scanlines. Let me know how that works out for you!
[/quote]

Will do guys, thanks. I forgot to mention that my monitor is mounter vertically since its a vertical cab (Ms. PAC Man style). Let me know if I need to do anything different. I thought I was running the desktop at 1024x768 already but will check it out.

[sharpfork]

Scanlines on a vertical, Tate monitor run vertically so you don't have to change a thing.

SIII + Cyanogen + Tapatalk 2

[Richie_jones]

Crafty I'm using the dvi signal on my cab, can I use a dvi to VGA adapter then your slg then another VGA to dvi converter to get me back to the dvi socket...

[CraftyMech]

From a technical standpoint, that should work Richie. Practically though, it depends on how well the DVI<>VGA adapters & the mini SLG get along. As long as all three adapters are chained together, interference should be minimal. However the only true test would be to try it out, if you happen to have those adapters handy or can borrow them.

If you are able to get VGA out of your video card directly, that would be preferred with the VGA->DVI adapter as the last piece of the chain. However, I'm guessing from your question that your video card might be dvi out only?

[Richie_jones]

Ok thanks crafty. 

I use my Bartop to play modern games also, so didn't want to loose my dvi connection.  As I'm unable to switch between VGA and dvi from within windows on the fly I would need to use the VGA connection all the time hence loosing the dvi quality.  I'll try it and report back here...

[Alcc]

Hey CraftyMech,
Does this converter work for a 19" LCD Monitor? If so, how can I order at least one to try it?

Thanks!

[Nephasth]

Hey CraftyMech,
Does this converter work for a 19" LCD Monitor? If so, how can I order at least one to try it?

Thanks!

Yup. Click the link in his signature.

[koolmoecraig]

Just learning about this now.  Really awesome work.

[Helder]

I know this is an old topic but whatever became of the CGA to VGA board that was being worked on? I would love to have the schematic so I can implement it into some projects for the retro consoles.

[CraftyMech]

I'm still working on the CGA2VGA board, trying to finish up a few lingering issues.

[Helder]

Are you still going the transistor/caps/resistor route or are you going to use a specific IC? I have a good schematic to take RGB and spit out component but I really would like to have it upscaled to work on modern TV's with out issue, but it seems that to properly upscale you will need ram/memory to buffer the image. Does your current design get around this ?

[CraftyMech]

The design uses several specialized chips, and a number of TTL logic chips. I'm planning on replacing the TTL chips with a CPLD to save on space and cost.

[Helder]

How far along are you in the project?

[jayfrost]

Craft. I would like to order one but cannot message u.  Please contact me if possible.

Jay frost

[CraftyMech]

Hi Jay, just send me an email at orders@craftymech.com

The forums here require a couple posts before you can send PMs.

[CraftyMech]

How far along are you in the project?

Sorry Helder, missed your earlier post. I don't have a release date yet, but the project is still alive and kicking. I wish I had more info I could share, but everything has taken longer than expected and I don't want to set any expectations for a release yet. The converter works great for some sources, not so much for others, so compatibility issues are what I am focused on fixing.

[Helder]

It's been a few months and wondering the status of the project.

[CraftyMech]

It's been a few months and wondering the status of the project.

So am I

Another side project exploded a few months at into a much larger endeavor: http://forums.arcade-museum.com/showthread.php?t=297247&page=65

I'm finally getting caught up on my pre-orders for that project, so can return my focus to the CGA->VGA board.