Dredd Lawgiver

It's an iconic movie weapon. DNA coded, voice activated, specialty ammo modes - the Lawgiver. I got turned onto the 2012 Dredd 3D movie a few years too late. It just didn't hit my radar until it was too late. The movie "flopped" on it's theatrical release but gained a HUGE following in the years after.

Back in 2016 I decided I was going to try to replicate the look and more importantly, the "function" of the prop I saw in the film.

I did some research and found out what display screen was used, now I had to figure out how to program that screen to match the movie. It took a while to figure out, but there are so many great resources available online.

The next big hurdle was how to make voice commands work. That took some investigating. Instead of detailing my trials and tribulations, I'll just cut to the good parts and list out the parts I used to make this thing work.

The star of the show is a Blue 2.2 inch 128x32 OLED Module I2C Display. There are two versions that you can get, but there are trade offs. One is very thin and the perfect choice to fit in the tight space of the prop gun, but it requires a zif connector to interface with the screen. The other version is bigger, but only needs simple soldering skills because it comes with a breakout board attached. Both versions a listed in the supply list.

Adafruit has a great tutorial on how to make the display work.

https://learn.adafruit.com/2-3-monochrome-128x32-o...

The brains of the prop is an Arduino Nano. I'm not going to get into how to program these, there are other tutorials for that. I'm not a coder by any means, but I was able to figure out how to make it all work.

During the movie, when Dredd is issuing commands to the Lawgiver, there are sound effects associated with that, in addition to the first "boot up" scene in the movie. I sampled the effects from the film and turned each unique sound into a wav file that is synchronized with specific actions.

And finally, the last major component is the programmable voice board. Without this, I don't think I would've been able make the voice activation work.

Blue 2.2 inch OLED display https://www.buydisplay.com/blue-2-2-inch-128x32-ol...

Blue 2.2 inch OLED display with breakout board https://www.buydisplay.com/arduino-2-2-inch-128x32...

SimpleVR Voice Recognition module (comes with microphone) http://www.elechouse.com/elechouse/index.php?main_...

Arduino Nano

DFRobot Mini mp3 player - https://www.dfrobot.com/product-1121.html

Battery - your choice. I use a 9 volt for the initial prototype switched to a 18650 battery stored in the forward magazine.

Momentary contact push button switches

Speaker

Various wires and connectors - it all depends on how you design your circuit.

Lawgiver model - I bought the Planet Replicas STL files and 3D printed the parts.

I analyzed the movie and determined the various modes that the Lawgiver was capable of. The opening scene shows Judge Dredd handling the weapon and initiating an ID Check. There is a sound effect associated with this scene that implies a "boot up" of the Lawgiver. I thought it would be cool to add the Halls of Justice logo to the screen as it "boots up". So I found an image and added it to the Arduino code.

There are several different ammo modes that Dredd uses to defend himself and enforce The Law throughout the movie; both specialty ammunition and fire modes. These were modeled into the code and the round count was noted and displayed as well. I decided that I would have the round count decline with each trigger pull, and make the specialty ammo modes changeable by a push button switch as well as voice changeable.

I also programmed in the "AMMUNITION LOW" message when round counts go below 10. The red LED also illuminates.

I initially used a prototype bread board to wire everything together, trying to get the smallest footprint I could so that it would fit into the Lawgiver 3D print. You can see examples of both OLED screens and the electronics mounted in the upper portion of the model (without the toy Glock installed)

There are a lot of design choices and options that were considered as I built this prop replica. In order to not change the appearance of the final result I incorporated the on/off switch into the non-functional "magazine" drop switch located on the right side of the Lawgiver, and I mounted a push button switch behind the slide release on the Glock. I mounted the battery and charger in the forward "custom ammo" magazine. The dummy bullets slide out to give access the 18650 battery, should it need to be removed or replaced.

Over the course of the build, and as I learned new "tricks" I added features to Lawgiver. I added sound effects for each type ammo shot. Examples -the sound of a Barrett 50 caliber rifle shot for the "Armor Piercing" trigger pull, a single round Glock being fired in "SEMI" mode and a synchronized automatic Glock firing with "RAPID" fire mode. Each specialty ammo has a custom sound effect associated with it.

A Hall Effect sensor was added in the Glock grip to spoof the DNA encoding feature. A switch is mounted inside the barrel end to activate what I call Convention Mode. If a person is cosplaying at a convention, they can put a magnet in the palm of their glove. While the magnet is present on boot-up, the process completes. If the magnet is not there, the ID check fails and an animation of the screen exploding is displayed (along with an explosion sound effect). The same sequence happens if someone other than The Judge pulls the trigger of the Lawgiver.

The single most requested feature I would consistently get is - did you guess? Double Whammy. So I added it. I made it so the specialty mode would use the range finder in the display (D:0.0) when the trigger is pulled and added some sound effects also. Note that I also added an LED that flashes in the barrel, synched with the trigger shot and the sound effect.