Dredd 2012 Lawgiver II functional build

Nicodema

New Member
And so it begins.

I thought I'd kick off a thread to document my build to share any insights that others might find useful.

The Aim:
To make an accurate replica prop which is both a working airsoft gun and has the characteristic working display from the 2012 movie.

Many people have created inert replicas, firing airsoft replicas and replicas with working screens, but I don't think many have gone for the full set. I don't intend to do voice recognition, since if Alexa and Siri both can't get that working well, neither can I.

After a good amount of research, I decided to base my build on the files available from Planet Replicas.

These are a good set of files, but there are definitely some practical issues with them that required rework. More on that later.

First step was to identify a good screen to use. From screen grabs I worked out that the original was most likely a 2.2" 128 x 32 pixel display. It's really hard to tell from the movie whether it's blue or just a very cool white which reads a blue due to the colour balance. So I bought some EastRising OLED displays from Ebay in both blue and white. Once I got them, I rigged up an Adafruit adapter board and wrote a little test sketch for a MKRZERO to see what I got...
IMG_1508.png

Not bad for now. That's one of the blue displays and as you can see the colour balance is pretty warm, so in real life it's very blue! Those are stock fonts and the voltages are sketchy so there are a few artefacts, but the gist is there.
 
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Nicodema

New Member
Next up, many printing...
IMG_1520.png

All parts will be printed in Ultimaker Tough PLA, most with PVA support, which makes pieces like the internal side plates much simpler to print. As you can see the sloped sections are printed as modelled.

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A number of prints later and I can start to see how things fit together. Turns out the displays are a perfect fit and the flexible PCB ribbon ends nicely at the top of the internal frame. The long, narrow block running along the top helps support the cowling that on the original was bent aluminium. I'll be needing to hog away a good part of that to house an adapter for the flexi PCB
 

MangyDog

Well-Known Member
I plan to do a law giver at some point but not as a functioning prop... But I forgot whats the base gun? A glock? Or something else?

It should be fairly easy fitting in a shroud over the base gun, as that's basically what they did in the movie. Adding electronics is as easy as a fitting a display and finding a 4ish cm by 2 ish cm space for a arguing mini to sit, and a battery somewhere.

My guess would be inside the special rounds magazine in the front.

Put in an end stop invite real magazine compartment and you could then have a semi accurate bullet counter. Just work out your fire rate, and bb count. And also wire up the trigger... The arduino could do the rest. (after coding in the stuff)
 

Nicodema

New Member
The base gun is a Glock 17. In my case, a KSC G17 with the stock plastic slide.
As for the ammo counts, I think you'll like my approach. More on that later.

So with more parts printed, it's time to dry fit onto the pistol and see how it fits.
IMG_1529.png

OK, not terrible, but the "beaver tail" doesn't fit onto the flare at the top of the KSC glock back strap. It's hard to see that it would fit onto any decent replica glock 17 that I've ever seen, so I'm assuming this part always sees a lot of love from the Dremel.

Note cocktail sticks, paper clips and solder used as temporary alignment "fasteners". Oh dear the name plaque is pants! Hopefully the Form1+ at Makespace can helps there.

It's also clear that if I was to go with the original single top block then I'd have trouble making the installation reversible. Basically the beaver tail and the whole front end attach to the top block via the side plates and to get that attachment rigid I'm going to want to use PLA weld rather than tiny fasteners. So, time for some Fusion 360 work.
Screenshot 2018-12-29 at 14.17.28.png

That's more like it. A space for my FPC ribbon adapter board, mounting screw holes and a take down interface using an M4 caphead and semi-captive nyloc, so that I can join and detach the rear of the gun once the cowling is in place. Happy!

Notice also that the spacing block on the back (shorter) part is itself shorter. This is an addition to support the inner rear cowl, that hides inside the curved top cap. The original design just had this reliant upon the rest of the parts for support. I do have wonder how they attached the bodywork to the real steel Glocks. There is no attachment geometry in the PR files, so I'll be creating my own, right now...

So, each piece that I've ended up altering has either been a lengthy, painful hack in Meshmixer, which I've had to do for the moving slide part (more later) or a complete remodel in Fusion 360, taking dimensions and inspiration from the PR files. Those files appear to have been created in a mesh based design tool, like Maya, 3DSMax or Cinema4D, which swamps Fusion 360's limited mesh editing toolset.
Screenshot 2018-12-29 at 14.33.27.png

This piece then is an add into slide firmly onto the under barrel accessory rails on the Glock frame. This was a good call as it took a couple of attempts to dial in the "finger" dimensions. The S5 is new and I hadn't got the horizontal expansion dialled fully.

A dab of acrylic weld cement (mine works perfectly on Tough PLA, yay!) and I now have a firm, sliding fit on the front end of the prop.
 

Nicodema

New Member
Oh yeah, these OLEDs are prone to fusing if your power rail gets too high. I was using an ebay special boost converter to supply my 12v display power, but if the input voltage gets too low the regulation goes haywire and output can swing upwards. I had bought these when I was making something that used a 2S LiPo rather than a single cell. Oops. Scratch one display. Good job I bought a few.

The replacement converter arrived and is perfect for the job. Actually basically the same size as an ItsyBitsyM4, so I'll piggy back the two and hide them in the over barrel section. I also got the smaller FPC ribbon adapter rigged up with the interfacing components to drive the display in I2C mode. That uses the fewest pins and hence interconnect wires from controller to display.
IMG_1549.png

I've drilled through the square dimple to let the red LED shine through. There's not going to be enough space to stow the Dotstars that I intend to use though. I'll be remodelling the display bezel to make a better job of that.
IMG_1550.png

I've got a strip of Dotstars (APA102), where the spacing is pretty much perfect for the red and green status LEDs by the screen. I like the idea of using those rather than standard LEDs so that I can control hue and brightness, while being able to daisy chain more off the same SPI pins if I decide I want muzzle flash or anything else later.

Next up, now that the electronics are working on the breadboard, time to start fitting the components to the chassis.
 

MangyDog

Well-Known Member
Rather than drill through the unused part of the display, in the hope that there might not be hidden transmission lines... Why not mount a small smd over it?
 

JOATRASH FX

Master Member
RPF PREMIUM MEMBER
And so it begins.

I thought I'd kick off a thread to document my build to share any insights that others might find useful.

The Aim:
To make an accurate replica prop which is both a working airsoft gun and has the characteristic working display from the 2012 movie.

Many people have created inert replicas, firing airsoft replicas and replicas with working screens, but I don't think many have gone for the full set.
First off, welcome to the RPF and with such an admirable project to boot!


As one of those who was most active early on in the Dredd prop/costuming craze, I studied the gun a lot, including looking into what it would take to do what you're doing. (I modeled the first 'accurate' Lawgiver, which was cast by the venerable Morganthirteen, that most costumers ended up using.) The thing you're going to have to accept is that you simply can't have all three because it isn't really physically possible. Accuracy (if you're after absolute perfection in regards to the prop) will have to take a back seat because there's simply no room for the display with the moving Glock parts there. You have to adjust the tolerances and thicknesses a bit for everything to fit. The top of the Glock grip frame will also tend to interfere as well. When I eventually get around to building a new LG for myselg, I was going to cut out large parts of the slide to minimize the need for thickening the gun too much. (Small note: I've never really looked too closely at them, but from what I remember, the PR files are not fully based on what was used on-screen. As I recall, they were taken and modded from early prototype tests or something.)


The base gun is a Glock 17. In my case, a KSC G17
And for those who start looking for Glocks, it should be noted that the THIRD GEN is the correct one. A lot of airsoft makers have started to switch to 4th gen.

Oh, and general consensus is that the display should be blue.

Will be following this one as well. Best of luck to you. You're off to a great start!
 

Nicodema

New Member
Thanks Joatrash, I appreciate the input. I took a good look through your posts before I kicked this thing off.

Yeah PR admit that their files are based on a prototype model, updated to bring it more in line with the screen used props. That's the thing I think, looking through the movie there are many shorthand versions used, some missing significant details, so you're always trying to hit something of a moving target. I'm gunning for pretty decent accuracy, but definitely ticks in the firing and display boxes.

Hi MangyDog, I may have confused you. I haven't drilled the display. That would basically explode in a cloud of glass shards! I drilled into the square depression in the bezel. Any LED needs to be inside the bezel so it's really just a matter of finding the best depth to mount it. The bezel attaches to the side plate of the frame, so I intend to mount the LED to the same plate, but have a hollow in the back of the bezel to accept the LEDs.

EDIT TO ADD: Ahh, I think maybe you assumed the bezel was part of the shipping display. Sorry, no the bezel I mentioned is the 3D printed bezel from the prop, which has the red and green LEDs in that get used for the DNA CHECK and the OUT OF AMMO scenes. Like some of the screen used props, the RP models don't have the hole for the top, red LED.

More progress content shortly.
 
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Nicodema

New Member
Display adapter mounted.
IMG_1557.png

The display has the blue painters tape on so I can slip the bezel over to check placement. Here the main top block is bonded to the side plates for good. Those huge tantalum caps are going to be a problem for the top cover though. Some rework definitely required.
IMG_1562.png

That's better. Step up converter and ItsyBitsyM4 inside the over-barrel cowl thing. You can just see the micro USB socket poking out. All interconnect is via kynar coated, single core wire-wrap wire.

Once this is all together I think I may design a PCB to take the FPC ribbon socket, SMD caps and resistors and also switch over to the SPI mode rather than I2C, because it's so much faster.

After much deliberation on how to get power from a LiPo in the front mag I've decided to go with an XT30. Hopefully the insertion force is a good balance between too stiff and too slack. Need to get the male connector set into the chassis, so rather than reprint the chassis again, I chose to step drill it and design/print just an interface cup...
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Snug fit, yay!
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This the view from below of just the chassis block, where the front mag slots in. If the gun was a spam sandwich, the side plates are the butter, this block is the spam and the outer bottom body section forms the bread. The "spam" needed a large amount of sanding to reduce the width enough for the sandwich to fit together, since the "slices of bread" are rigidly set a certain distance apart and the "butter" is a bit thick! I think I'm done with that metaphor now. Hungry too...

You can see my rail interface, bonded in place on the left of shot. So that's where the bottom of the Glock frame ends up once the gun is slide in place.

IMG_1563.png

Hurrah! The electronics still work. Obviously in Mega-City One 25 AP rounds is considered "LOW"

BTW, who else noticed that when Dredd blows a hole in the wall to escape Ma-Ma's minigun onslaught, his gun is magically flipped so that the display is on the RHS? Curse you, laws of cinematography!!
 

MangyDog

Well-Known Member
Isn't that display meant to be on the left face? So when held in the right hand (as is proper :p) the screen is readable to the user....

Also why such large tantiums? Power filtering?

Sorry if you already mentioned... But what are you using to control the display? Arduino mini?

And what is the display running voltage? 5v? I'm assuming your using a lipo with a buck boost and charger in one module?

You shouldnt need any extra power filtering... The arduino and power module has more than enough to run the display
...

Have you bread boarded this?
 

MangyDog

Well-Known Member
I really should really read the thread before asking stupid questions... Of course you bread boarded....

Is the display really 12v? Wow...

Well if your worried about voltage swings going too high, you could use a Zenner to dump the higher voltage?
 

Nicodema

New Member
Heh, no worries.
Yeah, the Vcc rail is surprisingly high. OLEDs aren't driven the same way as traditional LEDs.
I was about to pull together a zener based protection circuit when I realised the original step up board required 5v minimum and so bought the replacement which takes much lower input voltages.
The caps are fairly big it's true. It does seem to make a difference in preventing odd ghosting artefacts on the display though. Here's the reference circuit diagram FYI...
i2c-oled-diag.png

As you can see, it asks for some fairly serious smoothing. I could have used lower voltage caps on the +3v line, but I used what I had. When I go SMD I'll pick exactly what I need. It'll be crazy low profile in comparison.
 

Nicodema

New Member
So, back to that bezel.
Screenshot 2019-01-01 at 11.52.32.png

One complete remodel from scratch later and I now have something that will looks identical from the front, but does everything I need from behind...
Screenshot 2019-01-01 at 11.53.06.png

The two square wells take the SMD Dotstars (APA102) on their flexible strip, once trimmed to fit. The wires then run through the channel to the main OLED display well.
And the hardcopy...
IMG_1584.png
IMG_1585.png

I haven't posted any pictures of sanding and filling and sanding and..... I think that accounts for a good 95% so far. So happy I found some 3M red acryl (aka Bondo red spot putty). Most of the "knifing putty" we get in the UK is noticeably coarser and prone to graining up as you try to spread it thinly.
 

MangyDog

Well-Known Member
Ahhhh cool :) Thanks for the diagram, gives me some idea as well... At some point ill be doing one too... though not using an airsoft base will be making it completely from scratch and put in a solenoid blowback mechanism in it too
 
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