(Topic ID: 29684)

FS: LED OCD - Eliminate LED flicker/strobe/ghost - Control brightness


By herg

7 years ago



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  • 763 posts
  • 159 Pinsiders participating
  • Latest reply 1 year ago by MustangPaul
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    There are 759 posts in this topic. You are on page 5 of 16.
    #201 6 years ago

    Well shit, if he already has three installed, I'll take a look!

    #202 6 years ago
    Quoted from Mudflaps:

    Well shit, if he already has three installed, I'll take a look!

    I think Tad got the boards since his last pinball party so there is nothing to be embarrassed about. See you there tomorrow night.

    #203 6 years ago

    I am perpetually embarrassed. It's an occupational hazard of being me.

    Hasselhoff-Drunk.jpg

    #204 6 years ago

    Kyle, have you ever been stationed in Germany? I think they are the only people that like Hasselhoff as much as you do.

    #205 6 years ago

    I'm not really sure what you're getting at Stephen. I thought everyone loved David Hasselhoff.

    **Drunk posted pic of David Hasselhoff removed**

    #206 6 years ago

    I am tempted to give that a tilt. LOL

    #207 6 years ago
    Quoted from DCFAN:

    I am tempted to give that a tilt. LOL

    I wish you would have! My great grandmother was full blooded German, so I'm at least 12%, and I feel no particular affinity for Hasselhoff.

    Quoted from Mudflaps:

    Well shit, if he already has three installed, I'll take a look!

    I wasn't sure if you wanted to see the install process or just the results. Also, one cool thing we can do in a WPC is use the passthrough mode to toggle between normal signalling and OCD signalling. Anyway, I'll bring it, and we can decide if it's worth the effort.

    #208 6 years ago

    I can't wait for some more WPC boards to get made. Now that I have a TZ and a STTNG back....yeah.

    #209 6 years ago
    Quoted from herg:

    Also, one cool thing we can do in a WPC is use the passthrough mode to toggle between normal signalling and OCD signalling.

    I remember seeing this mentioned elsewhere. Is this for WPC only? How do you toggle this mode? (I didn't see it documented...) Thanks!

    BTW I'll send you some files later today.

    viperrwk

    #210 6 years ago
    Quoted from Frax:

    I can't wait for some more WPC boards to get made. Now that I have a TZ and a STTNG back....yeah.

    I just got an email from the PCB assemblers saying they are ready to ship to me. I'd estimate that I can start shipping them out by the end of the week.

    Quoted from viperrwk:

    I remember seeing this mentioned elsewhere. Is this for WPC only? How do you toggle this mode? (I didn't see it documented...) Thanks!
    BTW I'll send you some files later today.
    viperrwk

    It's on the WPC and Sys11 ones, but it depends on the firmware on the OCD board. The PC app displays a button if the firmware version is compatible. If you want, I could send you an updated PIC to swap into yours.

    #211 6 years ago
    Quoted from herg:

    If you want, I could send you an updated PIC to swap into yours.

    Awesome! PM sent. Now I don't hate you as much...

    viperrwk

    #212 6 years ago

    Signed up on the preorder page on your site just in case.

    #213 6 years ago
    Quoted from swampfire:

    One enhancement I'd like to see is the ability to quickly toggle between the current settings and a "passthrough mode", which emulates taking the LEDOCD out of the circuit (or better yet, actually takes it out of circuit). It would make it easier to do A/B comparisons.

    +1

    That's really an important feature, IMHO.

    #214 6 years ago
    Quoted from Frax:

    Signed up on the preorder page on your site just in case.

    The WPC boards in progress are plenty to fulfill all preorders and still have some for inventory. Sys11, I may have underestimated, and if all my preorders come through with purchases (unlikely) I will completely sell out before having any for inventory.

    Just a heads-up, I'm almost out of Stern kits.

    Quoted from altan:

    +1
    That's really an important feature, IMHO.

    It's a cool feature, but IMO, it's not core functionality. It works in the Williams/DE kits, and I can't add it to the Stern ones due to the hardware design and the way Stern scans the lamp matrix. They scan through the "rows" and have multiple "columns" turned on at once. The LED OCD hardware uses a 74HC238 demultiplexer to drive the 8 "columns" using only 3 outputs from the microcontroller. It's impossible (without a hardware redesign) to have more than 1 "column" active at the same time.

    #215 6 years ago
    Quoted from herg:

    It's a cool feature, but IMO, it's not core functionality.

    Thanks for the details. Just to be clear, I'm not saying it needs to be 100% pass thru. What I'd like to be able to do is a mostly accurate A/B comparison from what the factory state looks like vs. the optimization with the OCD. If you could "emulate" the factory state fairly close, that would be good enough.

    But then allow quick and easy swapping between the factory and original...

    #216 6 years ago
    Quoted from altan:

    Thanks for the details. Just to be clear, I'm not saying it needs to be 100% pass thru. What I'd like to be able to do is a mostly accurate A/B comparison from what the factory state looks like vs. the optimization with the OCD. If you could "emulate" the factory state fairly close, that would be good enough.
    But then allow quick and easy swapping between the factory and original...

    Just focus on an insert that's part of a group, like the bingo awards on Ripley's. Install an incandescent right next to it and set the incandescent insert to instant on/off (no fade time) as a control test. What brightness setting sets the duty cycle of the lamp to 60Hz, replicating the brightness and fade time of a normal matrix output? Ideally if you are wanting to match the brightness and fade time to an incandescent then you want to set the fade time to zero and brightness to whatever setting that would produce a 60/250Hz duty cycle (which should be 24% assuming 100% is the full 250Hz scan rate).

    #217 6 years ago

    I have two 95's on preorder herg . BSD needs one really badly , and bride would benefit from one for sure.

    #218 6 years ago

    Herg,

    any plans to produce this for any of the Pin2k stuff, since (I'm not running nucore)LED's seem to flicker like mad on the mission select inserts on RFM... alongside the menu showing it as all the bulbs having blown...

    Cheers
    Paul

    #219 6 years ago
    Quoted from toibs:

    alongside the menu showing it as all the bulbs having blown...
    Cheers
    Paul

    Even if Harold were to make a Pin2k version (doubtful), the board wouldn't draw enough current for that.

    #220 6 years ago
    Quoted from altan:

    Just to be clear, I'm not saying it needs to be 100% pass thru.

    Understood, but the best I could possibly do is to output at 125 Hz (like Stern) and try to match the duty cycle of the inputs. It would be like a purposefully dumbed down output. In the WPC case I can simply pass the inputs through to the outputs. The WPC was minimal firmware work, whereas the Stern would be a good bit more complex. I'm also not sure that I could fit it in the Stern code space without upgrading to the full version of the compiler. To make this worth the effort, I would be forced to raise the price of the Stern kit, which I avoid like the plague.

    Quoted from Crash:

    What brightness setting sets the duty cycle of the lamp to 60Hz, replicating the brightness and fade time of a normal matrix output?

    There is none. The OCD always outputs at 250 Hz, and it changes the brightness by reducing the amount of time a lamp is on during its 500 ns timeslot. Doing it this way prevents lower brightness values from flickering due to lower refresh rates.

    Quoted from toibs:

    any plans to produce this for any of the Pin2k stuff?

    Not at the moment. I'm not familiar with the Pin2k hardware, so I don't know how much effort would be involved. There's not a very big market, though, so it would have to be easy to be worthwhile.

    Quoted from toibs:

    alongside the menu showing it as all the bulbs having blown...

    Quoted from Crash:

    the board wouldn't draw enough current for that.

    Crash is right. The only way to do anything about this would be to waste power.

    #221 6 years ago

    To sideline the tech nerds from turning this thread into VCR instructions, I saw this board installed on a few games this weekend (Stern and Williams). What a difference! As always, pictures do not do it justice. It looks great and really makes the game pop. I'll be getting a Stern board soon.

    #222 6 years ago
    Quoted from Mudflaps:

    To sideline the tech nerds from turning this thread into VCR instructions, I saw this board installed on a few games this weekend (Stern and Williams). What a difference! As always, pictures do not do it justice. It looks great and really makes the game pop. I'll be getting a Stern board soon.

    I think this board would finally get me to switch my Spiderman to LED. Awesome product.

    #223 6 years ago
    Quoted from herg:

    There is none. The OCD always outputs at 250 Hz, and it changes the brightness by reducing the amount of time a lamp is on during its 500 ns timeslot. Doing it this way prevents lower brightness values from flickering due to lower refresh rates.

    So you're saying the LEDs still scan at 250Hz but the actual on time of each cycle is lowered? What an awesome solution!

    #224 6 years ago

    Apologies if I missed this, but this is just the playfield inserts right? I know it doesn't do the GI, but I presume that it also doesn't do the backbox lights, on say a System 11 machine?

    #225 6 years ago

    He said he was looking at GI but that was most likely not going to work out because of the amount of current involved, even with LEDs. At most you would have 18 lamps per string (4.5A) and with LEDs it would be around 0.75A just for a single string. Still, I would love to see this done simply for the sake of Data East/Sega games that like to flash the GI a lot and WPC games that use fading effects. Both are quite disorienting with the instant on/off effects of straight LEDs, especially in a darker room.

    #226 6 years ago
    Quoted from Crash:

    Still, I would love to see this done simply for the sake of Data East/Sega games that like to flash the GI a lot and WPC games that use fading effects. Both are quite disorienting with the instant on/off effects of straight LEDs, especially in a darker room.

    YES please. LAH has had me in fits - I've put incandescent back in the box, but the GI is still killing me and I'd rather buy a board to control them than pull them all back out. I really prefer the LEDs....

    #227 6 years ago
    Quoted from Mudflaps:

    To sideline the tech nerds from turning this thread into VCR instructions

    Dude, not only am I going to set the clock, I'm about to set up a scheduled recording.

    Quoted from Crash:

    So you're saying the LEDs still scan at 250Hz but the actual on time of each cycle is lowered? What an awesome solution!

    It would be so much easier to describe this using a whiteboard, but it sounds like you have the idea. As an example, imagine three lamps in the same column; L1 that is being driven at 100%, L2 at 20%, and L3 is off.

    At 250 Hz, each column is active for 500 ns. When the time comes for that column to be active, the power is turned on by the column transistor and the L1 and L2 row transistors are turned on completing the circuits for those two. The L3 is not turned on at all. After 100 ns, the L2 row transistor is turned off, but the L1 row transistor and the column transistor stay on. After 400 ns more (500 total), the L1 row transistor is turned off and the column transistor is turned off.

    Quoted from Aurich:

    Apologies if I missed this, but this is just the playfield inserts right? I know it doesn't do the GI, but I presume that it also doesn't do the backbox lights, on say a System 11 machine?

    It is only the lamp matrix, so in general, it is just the playfield inserts. There are exceptions. STTNG shield inserts are GI, so they're not controlled. The Spider Wheel items in the backbox of Scared Stiff are controlled by the lamp matrix, so they are controllable using OCD.

    #228 6 years ago

    I can't friggin wait to get these into TZ and STTNG!

    #229 6 years ago

    I'm glad to see that people are recognizing just how awesome these little boards are.

    One WPC95 incoming. Woo woo!

    -Cyan

    #230 6 years ago

    In case you haven't guessed, the new kits are starting to ship to guys who pre-ordered.

    I plan to give those guys another couple of days to complete their orders, then open it up to everyone else Wednesday. In the meantime, I'm still building cables.

    Here's a picture of some of the new boards in the process of final assembly just before testing.

    IMG_7520.JPG

    #232 6 years ago

    Tech question for Herg (and others who might have a thought about this):

    Given the frequency you're driving the lamp matrix, would it be better to have LEDs with longer (recombination) lifetimes to minimize strobing effects? I'm assuming given typical rise/fall times and a high input step current that this would be the determining factor to the LED's response from the board's input.

    OTOH, shorter lifetimes would mean better responsiveness to the board's inputs (?)

    Of course, getting this info from the vendors is another question entirely...

    viperrwk

    #233 6 years ago

    viperrwk,

    I haven't really given this any thought. Unless you're designing bulbs from scratch, you're going to be stuck with the LEDs that are available, and my recommendation would be to just buy a few and try them. I think you've just "out-nerded" me.

    #234 6 years ago
    Quoted from viperrwk:

    Tech question for Herg (and others who might have a thought about this):
    Given the frequency you're driving the lamp matrix, would it be better to have LEDs with longer (recombination) lifetimes to minimize strobing effects? I'm assuming given typical rise/fall times and a high input step current that this would be the determining factor to the LED's response from the board's input.
    OTOH, shorter lifetimes would mean better responsiveness to the board's inputs (?)
    Of course, getting this info from the vendors is another question entirely...
    viperrwk

    LEDs that exhibit light persistence? Where did you hear about these? Also the bias current should be fairly low or ghosting wouldn't be a problem.

    #235 6 years ago

    If you can see strobing at anything north of 120hz on the playfield, you need to go apply to be a fighter pilot, because the vast majority of the population can't. Personally, I can tell a noticeable difference in say PC game FRAMERATE up to 120hz or so, but actual flicker on the playfield or a monitor? If it's 75+hz it doesn't bother me at all.

    #236 6 years ago

    You don't have to see the flicker (as referred to by the IEEE) to be affected by it. Many studies and references have made mention of the idea that the human brain can detect flicker to 200Hz:

    http://www.cdiweb.com/datasheets/iwatt/WhitePaperHealthConcerns_Feb_2012.pdf
    http://www.xinelam.com/pdf/LED-Lighting-Flicker-and-Potential-Health-Concerns.pdf

    But my question isn't really about the health concerns directly (hell there are many more things out there that are bad for us than LED lighting in a pinball machine.) By driving the LED at a much higher frequency, we're likely to see differences in LED lamps that wouldn't be apparent at the lower frequency your typical lamp matrix runs at. Given this, I'm wondering what type of LED would be best as you may not be able to *see* why one LED is better than another but you may *perceive* that one is better than another. And I imagine at these frequencies contributing factors would be a LED's rise/fall times, recombination lifetime, capacitance, latency of phosphors, contrast between the highest and lowest emission levels and more.

    And I'm not saying that the LED OCD controller is bad here. Far from it. It is pushing the technology in a direction that has the potential to make the lighting and effects even better than it could ever possibly be with incandescent lighting because you have such fine grain control over what's going on.

    viperrwk

    #237 6 years ago

    If somebody has commented on this already I appologize, but can somebody chime in on the difference between using this board with standard LEDs and using premium non-ghosting LEDs without the board? In other words, if I already have a bunch of non-ghosting LEDs in my inserts, would I see any difference if I installed this and went back to standard LEDs. I know that LED OCD allows much more precise control of lights, but I'm more referring to the fading effects.

    #238 6 years ago
    Quoted from Jam_Burglar:

    If somebody has commented on this already I appologize, but can somebody chime in on the difference between using this board with standard LEDs and using premium non-ghosting LEDs without the board? In other words, if I already have a bunch of non-ghosting LEDs in my inserts, would I see any difference if I installed this and went back to standard LEDs. I know that LED OCD allows much more precise control of lights, but I'm more referring to the fading effects.

    Non ghosting LEDs have no fading effects, no brightness control, and they still strobe. Spend your money on the OCD board with Pinball Life's $0.39 Ablaze LEDs.

    #239 6 years ago

    I like the pinballlife 4 led super f'n bright.. dim as necessary.

    #240 6 years ago

    I haven't installed my OCD board in my Tron yet and before ordering some LEDs I had a question. I have tried LEDs once before in my CV and the strobing made it unplayable so I went back to incandescent. I have an ACDC Premium and enjoy the LED lighting (no strobing)so I figured my Tron Pro would probably look nice with LEDs. My question is in regards to strobing and the GI lights and what LEDs would be best used in the GI to not cause strobing. The OCD board takes care of the inserts but would LEDs in the GI cause strobing at well ?

    #241 6 years ago

    OK, I think I've given the pre-order guys a fair enough head start. If anyone else wants one, you can now order from my website:

    http://herg.homeip.net/ledocd/

    #242 6 years ago

    Viper, your first link is produced by a company that produces a "flickerless LED" bulb.. kind of biased. The second link says:

    "This paper assigns no health risk to the biological effects
    of flicker in the various LED lamps. The hope is that by
    discussing the issue of flicker within the power electronic
    community, it will be possible to decide as a community
    whether or not standards or recommended practices are
    necessary. We do not attempt to do so here. However, we do
    offer simple suggestions as to what should be considered
    when designing lamps, such as flicker frequency, angle of
    viewing, task being performed, spatial distribution, AC
    dimmer flicker, etc. Further, it is not difficult to create shut-
    down or other safety prevention circuits that prevent
    flickering in the 3Hz-70Hz range when the lamp is in failure
    mode. This is the flicker range that has risk of photosensitive
    epilepsy for small minority of the population. "

    3-70hz? That's a far cry from 200. They did go into detail about how flicker can still occur, imperceptibly, at say 120hz, but again... if you feel like you're suffering issues from any kind of lighting at 120-200hz, then I'd say you're in for a world of pain, very quickly, very soon. Incandescent bulbs WILL go the way of the dodo. Hope for your sake someone finds a viable solution before then.

    My brain can tell a difference... I can watch those "240hz" TVs and clearly see a difference. It's not a difference I LIKE, mind you, but I don't get a headache or see any issues with stuff above about 75hz for me, personally. Flourescent lighting is far more annoying to me.

    Anyways, sorry to hijack the thread with that, but I don't really think it was quite fair to use those two articles as reference to health effects of flicker when one is put out by a commercial LED producing company and the other specifically says that it was NOT attempting to even determine the health effects of flicker, but is more a general discussion of why flicker occurs in LEDs, and potential solutions to produce controllers that flicker at 120hz.

    #243 6 years ago

    Just put 2 more in (TZ and Getaway). Awesome stuff!! Thanks Herg....

    #244 6 years ago
    Quoted from Jam_Burglar:

    If somebody has commented on this already I apologize, but can somebody chime in on the difference between using this board with standard LEDs and using premium non-ghosting LEDs without the board? In other words, if I already have a bunch of non-ghosting LEDs in my inserts, would I see any difference if I installed this and went back to standard LEDs. I know that LED OCD allows much more precise control of lights, but I'm more referring to the fading effects.

    Yes, LEDOCD will definitely still help here, because "non-ghosting" is not the same as "flicker-free".

    #245 6 years ago

    Can this be used on GI in games like CFTBL and CV to fix the flickering in GI dimming? I prefer the inserts stay as-is with LEDs (instant on-off) but for the GI the dimming flickers too much.

    #246 6 years ago
    Quoted from tjsynkral:

    Can this be used on GI in games like CFTBL and CV to fix the flickering in GI dimming? I prefer the inserts stay as-is with LEDs (instant on-off) but for the GI the dimming flickers too much.

    If it's controlled by the lamp matrix, yes. I was wondering this myself for a JM I'm working on - seems like almost ALL of the GI is controlled.

    #247 6 years ago
    Quoted from swampfire:

    If it's controlled by the lamp matrix, yes. I was wondering this myself for a JM I'm working on - seems like almost ALL of the GI is controlled.

    It's not in the regular lamp matrix, the circuits are actually listed under the solenoid table.

    #248 6 years ago

    No, sorry, but it won't do anything for GI. There is a table in the manual for each game that shows which lamps are at which locations in the lamp matrix. If it's not in this table, it won't be affected by LED OCD.

    #249 6 years ago

    Correct, lamps in the lamp matrix are controller by TRIACS on the driver board. Wonder if someone makes a fading TRIAC, or if it's easy or practical to put capacitors in parallel with each string to make games that like to flash GI much less disorienting?

    #250 6 years ago

    Starting to think my only option to beat this dimming problem is to yank my LEDs from GI and go back to incandescent. I didn't mind doing it for CV, but I really like cool white LEDs in CFTBL...

    There are 759 posts in this topic. You are on page 5 of 16.

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