Applied Science - 2019-05-16
How to build a replica DSKY unit using an electroluminescent driver circuit and screen-printed conductive ink. Source code, PCB files, screen print graphics, etc: https://github.com/benkrasnow/DSKY_EL_replica Other folks in the community have been working on authentic DSKY replicas, notably, Fran Blanche: https://hackaday.com/2017/05/29/re-creating-the-apollo-dskys-display/ https://youtu.be/hiqibWP2WNA?t=647 https://www.patreon.com/AppliedScience
Every one of your projects these last months have been more ambitious than any one thing I have ever attempted. I don't know how you do it. Completely awesome.
@John Smith Savage.
Reality hits you hard bro!
Whoah, you're the aerogel guy
Jellapper Lökkäs wow, you don't have to be a dick about it
I would call it imagination and to have so much time to kill
@John Smith damn you really rekt him
Applied Science chooses to build an electroluminescent display and build the other things, not because it is easy, but because it is hard!
@Sean Spark I wonder what would happen if Jeri Ellsworth and Ben were to combine their DNA.
It’s all a lie. He actually did everything shown here in his shop.
Eating a bag of pinecones is also hard...
@andr27 That's not cool, it's warm as hell you liar!
ryan.m and that studio is on the moon! 🤓
Well Ben - you beat me to the goal for an EL DSKY display. Hats off to you. Should I even continue with mine I wonder....
@Zlo Zlo Sorry I wasn't clear. No, source for your "vivid, brilliant green" statement. I do recognize that 530 nm is the right wavelength for a vivid, bright green laser, but here we're talking about an EL phosphor, whose "nominal" wavelength is 530 nm. I'd like to know if you have any information showing the DSKY's display as being a vivid green, since the only color picture I've seen for an operating DSKY shows it to be a washed-out blue-green, similar to Ben's.
@BrightBlueJim I have no argument against your response. You could be right, and you have first hand experience with similar displays. My only evidence to the contrary are some of the films and images taken onboard the various flights where the color looks similar but slightly less blue. It could be bad color correction or degraded film. It could even be the film is responding to the light differently than it is perceived by the eye. I was just mentioning that it would be great to confirm the correct color somehow. Perhaps it is called out in one of the specs, or at least tracing the phosphors to the manufacturer and getting some confirmation.
Yes please do it the Fran way. Can't wait to see yours.
No
I said good day!
Just wow! That is awesomely impressive! Congratulations on surmounting so many obstacles!
Please collaborate
@913WildCat They already can since everything is open source.. I'd love to see the Youtube collaboration too.
The temptation to hook this up to an actual Apollo guidance computer is strong. But probably bound to make Marc cringe.
@penguins forall and it has been done now lol
I first read that as surrounding yourself with so many obstacals. I'm not fully awake.
You don't upload videos too often, but when you do they're good. :-)
Thanks to Applied Science, I make liquid oxygen and liquid nitrogen on demand in my basement! So far I have not attempted to replicate any of his other projects :)
We certanly do need more guys like Ben that can show other people the way to go and how to act mature and intelligent, people like Ben certanly does not grow on trees on Youtube i agree with that.
Some more EL folklore. In the 70's one of the ways we luminescent material was to add the zinc sulfide based powder to polyethylene and extrude it like a plastic bag. It was 4 ft wide and 3000 ft long. We could make a few colors like green or blue. We sought out the blue because it would excite a secondary emitter screened on the front of the panel. The secondary emitter was basically day-glow paint that would absorb the blue and re-emit another color. We could silk screen multi-color images on the blue panel and get a wide range of colors you could never get by EL chemistry. We even used color separation and the dot method used to print color pictures in news papers. You could have a full color photographic images. The silk screen process lacked the precision for consistent results but we did on a few occasions get great results. One application for large panels was to put billboard advertising on transport trucks. We did tile an entire dance floor with flashing 2 ft square tiles. The panels regardless of the size were all capacitive and thus hard to drive. We drove them in the low Khz range in resonance with an inductor. Decades before power mosfets we used bipolar transistors or SCRs in the inverters which ran directly from rectified line voltage. I haven't thought much about this for decades. It was my high school job.
you wouldn't happen to have any patents for those specific extruders, would you?
@SuperAWaC I don't recall a lot from 5 decades ago. There were no patents. The process was done in secret by a company that made plastic sheet. It didn't take too long to get a successful result. We made many panels from a 3000ft long roll. I think it was just ordinary poly plastic bag material.
You are on a whole other level. Insanely impressive!
This is the guy that CT'd a frozen chicken in his garage using old parts from eBay. On a whole other level is putting it lightly.
Well he is just an engineer. We do things like this everyday, but nobody cares. That is funniest part of profession.
@ESDBlog Engineers are for the most part, taken for granted by our society. You will see TV shows about doctors, lawyers, police, etc., but one about engineers and what they do is doubtful. The details are just not fodder for the "emotional" rush required by mainstream entertainment. However, one movie called "Quest for Fire" about pre-historic man, made a large point of show casing a tribe that had made huge engineering leaps over another tribe. The "engineering" tribe had developed ways to make fire by artificial means, pottery for food storage, advanced weapons (atlatl), and constructed shelters. Yes, the first leaps were made by people who took raw materials, and re-purposed them to solve a particular problem. i.e. Engineers.
@ESDBlog 513k care for this one ..
This is alot more DIY than you might think.
Looks great, and very interesting breakdown!
By chance, are you involved with CuriousMarc's project to restore an Apollo Guidance Computer, including the DSKY? If not, I have a feeling he and the team he's working with might be interested in your notes.
Came here to ask the same question, let us hear it Ben! :)
At the very end of CuriousMarc's latest video (Part 19) is his DSKY :)
@Testing Ben is in Part 20
If anyone else wants the link, here's part 20 of @CuriousMarc's series of the AGC restoration, feat. this display: https://www.youtube.com/watch?v=-f7SE-dDNA0
@Brian Ullmark she just relaesed a video showing her making snd showing off a T shirt. She sent one to Dave also.
Into the video 2.5 minutes and was laughing at the "spending 20 hours squashing bugs is enjoyable, in theory" . I think all true programmers, engineers and hackers feel this way, I have given up so many times working on a program only to walk away get half way across the room and go "what if we did this?" I would point out that anyone capable of doing this project would enjoy the "bug squashing" part much more than a puzzle labeled part 1, part 2, part 3.... just my humble opinion.
I love debugging but this drive to do it definitely depends on the tools available. A couple of months ago I was debugging some code for an old chip that I didn't have any manual for and no tools for. The feedback I got was "working", "half-working" and "not working". It's sometimes easier to start again rather than chase bugs :(
Finding a bug is certainly an exhilarating moment, but more in the way finally letting your dick out of the vice would be, to use an AvE reference. I do debugging when needed but definitely wouldn't do it "for pleasure"...
@Attila Asztalos ...as in, "it feels so good when I stop."
I hate it when I wake up at night and have an idea how to solve difficult problem. Good luck getting sleep before trying it out 4 am.
These HV chips were designed by Mead then Diconix (now Kodak) and originally produced by HP in the 1970s to drive an electrostatic inkjet printer known as the Dijit. The problems you experienced with the diodes were known to the engineers and I recall the explanation was a limitation of the silicon...
To be fair they write in the Conditions Column that they can only sink and source 1mA to clamp the voltage.
I think a lot of these "protection diodes" are more artifacts of the PN silicon stacking process during manufacturing, and less "engineered" diodes having usable specifications.
@mike brown Maybe but older CMOS chips got destroyed very quickly by higher voltages and only newer ones have the protection. If is is really just an artifact this should always be the case if the acutal way these chips are produced never changed that much.
I figure these chips are harder to use than just plain old H-bridges you can get in SOT-23…
Aaron H
The HV507 drivers were used in an electrostatic printer project I worked on 5 years ago. My solution to keep the HV507s from being zapped was to put a megohm resistor in series with each electrode line. The individual electrode capacitance was small, so the added resistance didn’t adversely affect the settling time. The current is limited to 300V/1Mohm = 300 microamps.
And yes, before this change, I had a tray of HV507 ICs and a Metcal soldering iron, and got really good at rework.
as always, im baffled by the amount of effort you put in every single video. Makes for a stark contrast to most youtubers. I can't say i'll build one, but i certantly enjoyed watching
me too. its so sexy.
It's a balance, "effort for a single video" vs "upload frequency". I like both types of YouTubers, but I'm so glad there's a place for both of them.
I do not think he is not doing any of these for a video, he does what he does and video is just the way he documents it.
You’re a one man R&D department.
Most of them are!
Company: "That'll be $500"
Ben: Bro I've got some Elmer's glue
'Squashing a bug that's consumed 10 or 20 hours of your life is pretty enjoyable in theory.' Best line ever.
programming is a harsh mistress.
@cmdraftbrn I see what you did there.
I'm not qualified to view your content. It's so cool though.
My thoughts exactly! Yet, here we are...
I think you are qualified to watch anything.
Did Fran put you up to this?
Fancy seeing you here
https://www.youtube.com/channel/UCfIJOyTKtSbfdXu9762CdIg watch this first, you may want change your comment
@D H it's a joke
He is stealing her project. What a shame. And he does it with modern components too.
"...so we're actually with in specs, which is nice." Nuff said
5:03 I just happened to be at this point when I saw your comment ;-)
And it still blows up!
Its really cool seeing EL inks being used again, back in 1996-1998 we were using screen printable processes for ITO, Barium Titanate, Phosphor, and conductive silver backplanes. We manufactured flexible membrane switches here in Australia, and utilised EL as spot backlighting for various elements, much more customisable than LED layers in our membrane switches. an example of a 5 segment display here https://sunindustries.com.au/wp-content/uploads/2014/03/sunindustries051.jpg the single hardest thing was connecting tails and imbalance of segments. second on that was the connection to ITO and the initial "turn on" failures of the panels. we got pretty good at it in the end, however it was very costly, and not many people wanted to pay for it. brilliant tech though.
you've got some awesome solutions to these problems, we also masked our phosphor layer, which meant that if the epoxy connection was outside the display area, the phospor was not excited, and the barium retained its insulation/capacitor functions
totally blown away by the sharing here, legend!
Thanks for sharing your experiences! It's always fascinating to hear from the people who worked on these things in the industry.
Did you contact the chip manufacturer to find out why the internal diodes weren't doing their job?
ESD diodes are typically designed for discharge events on the order of a few hundred pF charged to a few kv in series with 1.5Kohm or so. If you subject them to a 10nF capacitor with minimal series resistance the current/voltage spike at the pin can be much higher than during an ESD event and that will cause the chip the latch up. One solution to make the hardware completely robust would be to add a series resistor with every output to limit the current during a discharge event - whether or not an appropriate resistor value can be used without affecting the performance of the display is a secondary matter.
I'd really like to see what they did in the Apollo project - no fancy driver chips there, likely driven with individual bipolar transistors. Now THAT would be impressive. Could likely put THAT on a PCB, too, especially if he used HV bipolar SMT transistors, such as a FJV42/FJT92 pair from On Semiconductor
@Richard Pushman The original apollo project used good old fashioned miniature relays to switch the segments. 150 of them in TO-5 packages, all potted in resin behind the EL panel it's self. There was no such thing as a 300V BJT transistor in the late 1950s (or if there was, it was not considered reliable enough).
Fran from the franlab channel did a really good video series on the original display. She finds the exact relay they used and figured out they were something like $50 each or something.
Alex Wood $50x150=$7500 in Relays x 3 computers x 9 flights would be more than $200000 just for the flown computers. No way they would spend that much for a few displays in disposable tinfoil cans. (Joking of cause).
Funfact: The Apollo program cost 112 Billion Dollars, adjusted for inflation
It's a pity that there is no Nobel Prize category for applied science....
they would waste it on chelsea manning even though that as un applied science.
Wow! I'm sure after you blew out 10 or so HV507s at $14 each, you got really determined to win and you did! Congrats, thanks for the detailed debugging discussion. I hope your getting a little Microchip kickback because I suspect they'll be selling a bunch of HV507s in the coming months.
Or not, now that we all know they don't have working protection diodes.
@Ian Oliver It's not that they don't have working protection diodes, it is that the scenario exceeded their specifications. Protection diodes are really only meant to clamp/dissipate short relatively low energy impulse bursts like static shocks, not to be able to take the brunt of a large overvoltage. It is like complaining that the body diode of a fet cant sustain the full forward current for a significant amount of time ... because it was never meant to.
Power electronics is quite painful. A couple of comments:
- The drivers protection diodes are most probably there (they are an inevitable byproduct of the transistor construction), though they probably die after you yank them to -40V. The problem is that they can only conduct so much current (it should be specified in the datasheet). The current is given by Ic = C * dv/dt (capacitor current). If all the other drivers try to force a large dv/dt the current will be just to large for a single driver to handle even if the output transistor is still ON and the protection diode is there in parallel to give a hand.
- If all segments are lighted up except one, you might still have problems on just that one driver, no? If I were you I would put limiting current resistors in all drivers outputs (yep, it's a pain in the ass).
With that done you might not even need anymore to shift the control signal with respect to the common signal.
"you learn something and feel good about it". SCIENCE ❗️
So I can finally have the 1980s style bar graph/percent bar display for my EVs power consumption (volts, amps, battery % etc) and regen that I’ve always wanted? 🤤🤤🤤
Ohh yessss!!
Oh man and a Honda S2000-style dash, but for amperage instead of revs?
My boner cannot be contained.
Can't wait to see how much brighter it can get.
Keep up the good work.
26:49 unforseen consequences
Such joy seeing an AppliedScience video pop up in the feed! Best channel I’m subscribed to hands down
I really believe this is the best channel of the N-American continent, but the thought emporium is getting close.
Those 2 channels are just as rational, just as scientific, both channels are to the point, and both channels feature scientific projects that took a lot of effort.
That was some hardcore fault finding, I imagine you were rather pleased with yourself at cracking that one 😎
Its 3:30 in Kiev, but it doesnt matter, THE GREAT ONE HAS RETURNED
Слава Україні. :)
I like how he's giving tips as if I'm actually able to try this myself
talking about bugs
".. pretty enjoyable.. in theory"
Superb pulling together of a load of different skills. Congratulations.
I'm guessing you're talking with CuriousMarc. By the way, it was folks like you who got is to the Moon. Decades ago I got introduced to a J--K flip flop and very few younger guys even know what it is. Its great to see someone who is stretching my understanding of analog circuits. Thanks.
I go here to see unimaginable things done in a garage. I feel like I should be prepared for this after that electron scanning microscope build but I still get surprised every time. Great job and thanks for sharing!
Amazing work! And still days away from the Apollo 10 launch!
Those silver dots on the display got me wondering. I was guessing that the actual DSKY had independent common electrodes for each display register; hence the many visible electrodes. Thankfully, some of the original schematics are now publicly archived. Have you seen these? This is full of great info on the AGC in the LM Module. https://archive.org/details/acelectroniclmma00acel_0
Looking briefly at the original AGC display schematics (Figure 4-229) from the LM, they seem to have completely isolated the signal circuits by using a matrix of specialized miniature relays! This is cleverly done by the using double coiled relays and a few diodes to creating a basic AND gate to drive each segment.
I'm sure there's a lot more goodness here that I miss too.
22:20 ah, this made my day. I feel your pain
In My MANY years watching Science and Engineering material on Youtube, this was by far the most impressive combination of ideas and innovations by way of defeat and victory yet; I am in awe !!!
Thank You Professor Ben !!!
Also thanks to CuriousMarc and his restoration of the Apollo Guidance system !!
Amazing content - especially the availability you have given to open source. Well done sir.
6:40 I wonder if the multiple common connection points to the glass were there for redundancy. Or perhaps they were made using springs, in which case redundant contacts would be a very good idea.
In 1972 I developed a large format 5 x 7 dot matrix EL display digits. About 4 x 6 inches in size. Each half inch square dot had storage and was driven by sort of an R-S flip flop made from cad sulfide photo cells. I had cell arrays made on anodized aluminum foil. Illumination from the back of the EL pixel turned on a cad cell which drove that cell forming a latched driver. We powered down the whole digit to clear it. We couldn't justify 35 drivers or 35 wires for every digit. Multiplexing resulted in too small a duty cycle for any reasonable brightness. A second photo cell on the back of the foil in parallel with the front one was used to trigger the latch. That was driven by a multiplexed EL array which didn't have to be fast or bright. A single scan from this array wrote data to the display which was latched. We struggled to drive these high voltage AC displays in the 70's but the photo cells did it. I used an Intel 8008 processor to drive the system. It was a lot harder in those days.
That's pretty epic!!
I can't get enough of your content, awesome video, i pay a lot of respect for your knowledge <3
These are really cool! Is your education in applied physics?
@Applied Science your 15-30 minute videos teach me more than months of school ever could have.
Engineering is just applied physics...
@BrightBlueJim Physics is just applied mathematics.
@L0j1k maths is just applied logic, and logic is applied thinking.
Intra Meta Archi thinking is applied living
Great project! You are a very interesting person - I wish you are my neighbor! Thanks for sharing your projects!
Did you just use a peltier to solder that flex connector?! That is amazing, I never seen anybody do that. Great idea!!
Are you sure that's a peltier? Those tend to come with colored leads because polarity is kinda important. It could also be just a PTC heater, that wouldn't care...
Oh boy, I was waiting for this since you've published how to make a custom liquid crystal display! Thanks for sharing!
Make a DRO display
Or a whole DRO setup would be way more cooler 😁
I'm Glade I wasn't doing this project. 😁 In 80s, I was blowing CMOS chips and I thought they were protected by diodes. I figured out that I had surges on the PS lines and diodes were not able to surpress the surges. I fixed the issue by adding multiple types of caps on PS lines. You could have used 150 resistors with the high values on your second board to surpress the extra charges. Another thing is that you could have multiplexed the segments then you needed a fewer lines. However, your ITO lines would have been more complicated and your display wouldn't be very bright.
In fact, the cap charging problem is a common issue with the high speed PCB 's. The effect of cap causes lines to malfunction.
This is some beautiful work you've done: I've seen one of the originals in person and was always fascinated by them. Glad I'm not the only one!
Absolutely fascinating video. I saw your other video from last year just a few days ago, and was already very interested. This is amazing, i can't believe you did this all on your own without a giant manufacturing plant.
I always have to stop the videos when you get to the coding parts, b/c that's literally a different language to me and i don't understand it at all. But the chemistry, physics, and electrical engineering aspects are so amazing. I love this channel
EEVblog - 2019-05-16
Epic!
Ennar - 2019-05-16
Makes me wonder if you'd have your next Multimeter have an EL display, just because you could.
TheDrunkenMug - 2019-05-18
@Ennar yea Dave please build us an green-blue EL Digital multimeter with an uA range measurement function,
and then call it the 'Apollo precision DMM' :D
oytunsan - 2019-05-24
While I was watching I was also wondering "What would Dave think ?"
Rui Kazane - 2019-08-06
"Thing of beauty....a joy forever"
6Diego1Diego9 - 2020-09-12
are you familiar with what he's talking about dave?