While no doubt this is a lot of work and what I'm about to say is no slam on your effort, but I for one actually prefer the crispness and rapid response over the lazy incandescent bulbs. I'm sure I'm not in the minority on this.
If wpc designers had cheap LEDs and the budget to use them, I believe 100% they would have.
Quoted from castlesteve:While no doubt this is a lot of work and what I'm about to say is no slam on your effort, but I for one actually prefer the crispness and rapid response over the lazy incandescent bulbs. I'm sure I'm not in the minority on this.
If wpc designers had cheap LEDs and the budget to use them, I believe 100% they would have.
The games are programmed for the slower response time. Not like we are talking about seconds here, it is small fractions of seconds. And by the way, the response time can also be set with this board to your personal liking. 
Take a look at WoZ. Keith has chosen to make the inserts have the slower response time on this state of the art machine. Best of both worlds. The bright sharp light of multicolor LEDs and the twinkling of an incandescent! The WoZ inserts look AWESOME and this board basically allows an older machine to look the same. Lyman has done similar on ACDC and he *is* a designer from back in the WPC days...
So you're driving the LEDs at 250Hz, that means they would have to have a response rate of 1/250 of a second, which I'm guessing is too fast to notice any flicker? You would be going from a .016s to a .004s response rate, quite a difference. As for the dimming, I understand that this board intercepts the lamp matrix string and the driver board, eliminating some limitations of the existing hardware. But those appear to be transistors for the rows and columns on your board. How can these vary the voltage going to the LEDs? Are they actually triacs?
Quoted from Crash:that means they would have to have a response rate of 1/250 of a second, which I'm guessing is too fast to notice any flicker?
Yes, the second you install the board and power up, the LED flicker is completely gone! Believe me, I am someone who can really see the flicker and gets a headache from normal LED'ed games. I was amazed. No flicker or ghosting and no headaches. Having the further ability to customize to personal taste is the icing on the cake. Customizing is what LEDs seem to be all about.
Quoted from herg:It has been a while, so here's a quick update:
- I have four of them in my machines, and they're staying there.
- PT has one. He has installed it in his No Fear.
- One is ready to be tested in a System 11 (with interconnect) once the owner of the machine is ready.
- I've nearly completed the board modifications, and I intend to have a bigger batch of PCBs made in October.
- I intend for my TOTAN (including the board) to be available for play at MrWizzo's NoVA pin party this Saturday, Sept 29.
- I've created a website using my mid 90s web skills that mostly just repeats this thread.
- I don't want to do pre-orders, but if you're interested in getting one, contact me through the website or PM. Having an idea of how many to make would be really helpful.
http://herg.homeip.net/ledocd/
Great work Harold. Can't wait to see this thing in person.
This has the potential to be one of the most significant mods we've seen in a long time. It basically eliminates all the main arguments that people have against LEDs.
Quoted from herg:I haven't even looked at Capcom, so I don't know the difficulty level. It's certainly a good way down the road.
Capcoms are basically the same as the Sega Whitestar and Stern matrixes only 8x8 instead of 8x10
22N10L mosfets for the rows and VN02 relays for the columns, but it's a pair of 8x8 matrixes so you would need two of these boards to work in a Capcom
Quoted from Crash:How can these vary the voltage going to the LEDs? Are they actually triacs?
They don't vary the voltage. The duty cycle is varied by turning off each of the row transistors at the appropriate time during the column active time. Think PWM, only more complicated.
Quoted from kbliznick:Capcoms are basically the same as the Sega Whitestar and Stern matrixes only 8x8 instead of 8x10
22N10L mosfets for the rows and VN02 relays for the columns, but it's a pair of 8x8 matrixes so you would need two of these boards to work in a Capcom
Thanks for the info. I'm concentrating on getting WPC finished before moving onto other machines, though. Well, WPC and older Williams since those should just be different cables with no board changes necessary.
Quoted from Crash:How can these vary the voltage going to the LEDs? Are they actually triacs?
I would imagine he is using PWM to control the dimming. With a refresh rate of 250hz you can "flash" the led so fast you don't notice it but the overall effect is dimming. Now at some point the LED will be so dim that you might see some flicker due to the PWM being so short.
PWM is Pulse Width Modulation. at 250 HZ the led has 250 opportunists to either be on or off. so at full brightness the the led will be on all 250 pulses. at 50% it will be on for half and off for half, flashing at 250 times per second. but this is so fast that due to POV (persistence of vision) you see a dimmer LED and not one flashing at 250hz. At 25% brightness the LED is on 1 in every 4 pulses.
PWM is all around us. Its how digital attempts to appear analog to us humans.
I could be wrong about how this board is doing it but if it was using PWM that this explanation should be right.
Op beat me to it.
Quoted from Pugsley:I could be wrong about how this board is doing it but if it was using PWM that this explanation should be right.
Close, but it's not limited to on/off during a column active time. At 250 Hz, with 8 columns, that is 500 usec per column strobe. To light an LED at 50% brightness, it turns off the row transistor after 250 usec. For 25%, after 125 usec, etc. That way, the LED continues to be pulsed every 4 msec, and there is no weird cadence created by trying to light the LED... say 3/10 times to get 30%.
Quoted from castlesteve:I'm sure I'm not in the minority on this.
I'm sure you ARE in the minority. So there.
I think I read somewhere about eliminating GI strobing but can't remember, can someone post a link? If there's no solution to GI flicker one could just install a capacitor in parallel with the main branch and that will smooth out the irregular rectified wave to make this:
Look like this:
Unless using a a capacitor would be impractical, but it should work with the low power draw of the LEDs right? Only the playfield LEDs would really need it, so maybe buffering just the 2 playfield strings. Jump to 2:50 in this video where he adds capacitance to the circuit:
Okay, so with my basic electronics knowledge...
Capacitors will not rectify a waveform in the way you're talking about. What you're showing in your first picture is a half-rectified alternating current waveform that's gone through one or two diodes (can't remember). To fully rectify the waveform to straight DC like your second picture, you need four diodes. Two of them rectify half of the waveform, the other two get the other sweep. If you're only rectifying half, you get power spikes and drops, just like with normal A/C, just at half the severity and no polarity shifting. It's all + or - voltage.
The capacitor can help in the half-rectification scenario because half the time the lamp is effectively not getting power. The capacitor should assist with smoothing out those transitions, but will not be a fully straight DC output.
Believe the "premium" LEDs are using capacitors in order to prevent ghosting. When there's not enough current to actually supply the capacitor from the bleed voltage present on the shared line, then no partial lighting of the lamp occurs.
Someone slap me down if I'm wrong. I'm still learning and I don't mind if this is incorrect.
*edit* Okay, apparently I have *no clue* what I'm talking about. i can't listen to the audio on that vid right now but I see what you're talking about. I have no idea why just adding the capacitor would change the waveform like that. Hrm. 
Actually a half rectified wave only has a 50% duty cycle and only needs a single diode. A full rectified wave, like what I have shown, requires a bridge rectifier (hint hint Jason) to fully convert the sine wave into a pulsing wave with only positive voltage at double the initial frequency. The frequency is doubled with a rectifier because a single cycle of AC is a peak followed by a trough. Peaks and troughs are the same thing after rectification.
What the capacitor would do is buffer the brief dropoff time between cycles, eliminating flicker. It charges up during the peaks and discharges during the troughs, effectively taking up the slack when the voltage is not at peak voltage. It has nothing to do with ghosting, which does not happen in the GI circuit. Speaking of ghosting, this board should eliminate this too right? No false triggers due to ghosting?
GI is not rectified, it's just straight AC. The smoothing technique Crash mentions is common to use on rectified AC to smooth it into DC, and there's two big caps on the WPC power driver that does this for the lamp matrix.
Crash's top pic is full-wave rectified, but that's not what the GI power looks like. You could build a board with bridges and capacitors to get smooth DC for GI, but LED OCD does not attack this issue. It does not touch GI at all.
The premium LEDs have small scale versions of the full-wave rectifier/capacitor circuit, and are actually a good solution to GI flicker due to AC. GI flicker due to attempted dimming by the power driver is another issue altogether. I haven't looked into it, but I think you'd need bigger caps than would fit in a bulb.
I think the best solution to the GI problem (that would still work with an original power driver) would be an all hardware solution with rectifiers, smoothing caps, and an adjustable switching regulator. You'd end up with a lot of hardware, though.
Again, this is slightly off-topic since LED OCD does NOT address GI.
Quoted from Crash:Speaking of ghosting, this board should eliminate this too right? No false triggers due to ghosting?
There's a section on the usage page of the website that goes into detail on this, but in short, certain combinations of bulb types and settings can still result in ghosting, but you can work around it with corrected settings. There are no false triggers.
Not quite that simple. While using a mix of incandescent and LEDs, setting the incandescents to 85% has eliminated all ghosting during my testing.
I can't say for sure without doing a specific test, but I have not noticed any issues with setting LEDs to 100%.
Edit: One issue with setting the LEDs to 100% is that I can't see to play the game due to the intense brightness.
OK, I did some tests with CT Frosted LEDs set to 100%. The only case I saw ghosting was a 2 bulb situation. 2 LEDs in lamp #35 set to 100% caused ghosting on lamp #45. I decreased lamp #35 to 90%, and the ghosting at #45 was very close to gone. At 86%, it was completely gone. This is likely dependent on the type of LED also.
Would this technically mean the board wouldn't work with premiums? Wouldn't the capacitors ride out the low cycles and eliminate any fading?
Quoted from Crash:Would this technically mean the board wouldn't work with premiums? Wouldn't the capacitors ride out the low cycles and eliminate any fading?
lol, that would be rather unfortunate and ironic in a way..
Nope, CT Premiums work fine. The extra circuitry inside them causes them to not light at all until about 40% duty cycle, but if you set the minimum brightness for them accordingly, they will fade on/off just fine. Since they jump from off to 40%, it's not as smooth as other bulbs, but it's still an improvement over using them without the board.
If you already have a machine full of Premiums, rest assured you won't be forced to choose between not being able to use the board and swapping out the bulbs. If you're buying bulbs to use with the board, however, they would not be my first choice. My personal favorite so far are CT Frosted. They're relatively inexpensive, plenty bright, and work fantastically with the board.
I'm working on it. Production PCBs are on order and should be here in a few weeks. A little time to build some up and test, and I'd estimate a small number will be ready for sale by mid November if all goes well. Once they're ready, I'll be going down the list of people who have PM'd me to offer them for sale.
Quoted from Crash:Is $150 a realistic price point? Seems a little high for just fading LEDs.
It removes flicker, removes ghosting, gives individual control over each LED brightness, and yes, makes the LEDs smoother like a real bulb. People spend a ton of money putting LEDs in pins and this makes them look a lot better. It also lets you buy cheaper LEDs and make them look better than the top of the line no flix/no ghost...
Quoted from herg:I'm working on it. Production PCBs are on order and should be here in a few weeks. A little time to build some up and test, and I'd estimate a small number will be ready for sale by mid November if all goes well. Once they're ready, I'll be going down the list of people who have PM'd me to offer them for sale.
Excellent news! Here's to hoping I'm high enough on the list for its debut! 
Quoted from Crash:Is $150 a realistic price point? Seems a little high for just fading LEDs.
I can't say what it's worth to you. That's for you to decide, though saying it "just fades LEDs" is selling it quite short.
I can say that based on my best estimates, I'm going to have to sell at around that price point to make it worthwhile for me to do. I'm not going to get rich doing it. I hope that I might be able to eventually break even on what I've spent developing it. If not for the love of pinball, this never would have happened.
On a side note, this is now bordering on "Marketplace" discussion. If it needs to be moved, feel free to do so. Can I move a thread I started?
Quoted from herg:I can't say what it's worth to you. That's for you to decide, though saying it "just fades LEDs" is selling it quite short.
I can say that based on my best estimates, I'm going to have to sell at around that price point to make it worthwhile for me to do. I'm not going to get rich doing it. I hope that I might be able to eventually break even on what I've spent developing it. If not for the love of pinball, this never would have happened.
On a side note, this is now bordering on "Marketplace" discussion. If it needs to be moved, feel free to do so. Can I move a thread I started?
It's worth it to me for sure. Hal, I finally read thru the thread. Amazing stuff and pretty groundbreaking. Again, I wish I could understand it fully. I think you have grabbed a tiger by the tail. Have you patented it? Please consider doing so.
Please put me down for one that I would like install in my F-14 when it comes.
Dan
Dan,
Thanks for the encouraging words. I'll put your name on the list, but F-14 is a System 11 game, and I have yet to be able to test with a System 11. Soon, I hope.
add me to the list as well
and +1 on MrWizzo's comment about applying for a patent on this. definately protect your work
Quoted from herg:Dan,
Thanks for the encouraging words. I'll put your name on the list, but F-14 is a System 11 game, and I have yet to be able to test with a System 11. Soon, I hope.
You may use mine when it gets here. Happy to contribute. Please do not let anything out until it is patented. You deserve every benefit of your inginuity like maybe selling the rights to a larger manufacturer for whatever.
Who knew that in addition to Andrea, my discomfort playing your TOTAN because of my vision issues with LEDs would help contribite to the expositon of your EE genius! Cool stuff!
Dan
Quoted from MrWizzo:Please do not let anything out until it is patented.
See you in 2016! Seriously, people vastly underestimate the time and expense of getting something patented:
http://inventornotes.com/2011/03/04/how-long-does-it-take-to-get-a-patent/
Quoted from Frax:At 150, 1.19 for supers and 1.59 for premiums, .69 for ablaze or frosted, you could save like 30-80 $ on your led kit...I'd say that it balances out for the benefits it gives.
Or 1.55 Euro or whatever they cost for the NoFlix PLUS bulbs.
Even if filing a patent or protecting your IP is cost-prohibitive for you at the moment, there are a lot of things you can do if you believe your idea to be worthy of a patent or protection.
You should immediately draft invention disclosure documentation, and get it notarized with a date on it.
You can also file a provisional patent for $125 because you are a home inventor. This gives you a year to decide if you want to get an actual patent on the device. Like a trial period that allows you to sell it to see if it makes enough money to be worth it, before deciding to plop down the 5 grand on an actual patent.
Hope this helps. Not a lot of people know how easy it is to generate a portfolio of IP, even for a home inventor.
Quoted from jayhawkai:See you in 2016! Seriously, people vastly underestimate the time and expense of getting something patented:
http://inventornotes.com/2011/03/04/how-long-does-it-take-to-get-a-patent/
Maybe so, but expressing concern on behalf of a friend is never overkill.
Quoted from Wolfmarsh:Even if filing a patent or protecting your IP is cost-prohibitive for you at the moment, there are a lot of things you can do if you believe your idea to be worthy of a patent or protection.
You should immediately draft invention disclosure documentation, and get it notarized with a date on it.
You can also file a provisional patent for $125 because you are a home inventor. This gives you a year to decide if you want to get an actual patent on the device. Like a trial period that allows you to sell it to see if it makes enough money to be worth it, before deciding to plop down the 5 grand on an actual patent.
Hope this helps. Not a lot of people know how easy it is to generate a portfolio of IP, even for a home inventor.
Hey, Jayhawk! What Wolf said! 
Dan
Frax said:
At 150, 1.19 for supers and 1.59 for premiums, .69 for ablaze or frosted, you could save like 30-80 $ on your led kit...I'd say that it balances out for the benefits it gives.
Herg said:
Or 1.55 Euro or whatever they cost for the NoFlix PLUS bulbs.
HERG for president. Write him in pinside!!!
Dan
Quoted from MrWizzo:It's worth it to me for sure. Hal, I finally read thru the thread. Amazing stuff and pretty groundbreaking. Again, I wish I could understand it fully. I think you have grabbed a tiger by the tail. Have you patented it? Please consider doing so.
Please put me down for one that I would like install in my F-14 when it comes.
Dan
Who is this Hal you speak of?
Quoted from jayhawkai:See you in 2016! Seriously, people vastly underestimate the time and expense of getting something patented:
http://inventornotes.com/2011/03/04/how-long-does-it-take-to-get-a-patent/
It is getting faster these days. About 2 years or less if the inventor is aggressive with discussing the application with the patent examiner and amending the claims to be fairly narrow. Believe me, I know
Quoted from DCFAN:It is getting faster these days. About 2 years or less if the inventor is aggressive with discussing the application with the patent examiner and amending the claims to be fairly narrow. Believe me, I know
Well that's good news. Are you patenting green LED cat eyes?
Quoted from Wolfmarsh:Even if filing a patent or protecting your IP is cost-prohibitive for you at the moment, there are a lot of things you can do if you believe your idea to be worthy of a patent or protection.
Thanks for the info. I'll look into it. Though the general idea has been discussed quite a bit since LEDs started being used in pins, this particular implementation is different than I have seen discussed elsewhere.
The software on the microcontroller is what I believe is truly unique, and that is both copy protected and copyrighted. It sucks that in a closed community like pinball that I even have to worry about it, but I guess that's life. We've seen it happen before.
I also have a design notebook and configuration management tool to track all software and hardware changes.
Quoted from jayhawkai:Well that's good news. Are you patenting green LED cat eyes?
I am not allowed to get a patent 
You rock herg 
We are all looking forward to your truly innovative product! LEDs with all the benfits of incandescent...AWESOME!!!
The naysayyers...well they can suck it! 
A patent for such a niche market....realistically not really practical.... if you want to do something like that look more along the lines of what Wolfmarsh was talking about....but as you mentioned your software is at least protected so you would probably be fine with just that....but I am no lawyer!
Anyway, can't wait for this led solution to be installed in any of my led machines!
Quoted from DCFAN:jayhawkai said:
Well that's good news. Are you patenting green LED cat eyes?I am not allowed to get a patent
DCFAN is reluctant to discuss this in public, but he is an animal lover and participated in the "Pets from Chernobyl to the US" adoption program.
Dan
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