Metro Exodus Dosimeter Rework

[SpartaWorkshop]

Hey y'all. Its been some time!
A couple of years ago, I went through the rabbit hole of trying to accurately replicate the Dosimeter Artyom wears in Metro Exodus. Needless to say, this was a worthwhile attempt (which got me into 3d printing), but it wasn't good enough for me. A little bit less than two years later, I learned to use fusion360 more and stopped relying solely on Netfabb and game model rips as they were faceted and not good enough to print.
Rather than risk going insane trying to repair and rework the game model, I decided to model the damn thing from scratch. Here are the results:

Its not 100% perfect, but its still miles better than the first or even the second attempt I made.
I still have to model the Geiger–Müller tube, but other than that, its ready for small revisions to fit the electronics.

Speaking of electronics, I came up for a janky, yet brilliant way of making it look like it works. After doing some research, I came across this video, which pretty much solved all of my problems as there was no need for me to do anything besides trying to adapt their idea into my design. No coding was needed, which was a huge relief.

Since a lot of people expressed they want the files to make their own replica, be it for cosplay or LARP-ing, I want to make this thing as cheap and easy as possible to make. The problem I'm facing now is the voltmeter itself. I ordered a couple of those from an Ukrainian seller on Etsy, but when I received them I was surprised that they wouldn't work as they were simply too high to fit properly, which in turn made them look awkwardly out of place. I got around that problem by thickening the base plate and creating a recess for the rest of the voltmeter to go into. That works but its not good enough. Ideally what Id need is a small mechanism, no taller than 16mm that can move a needle. Ill try to figure that one out, but if anybody has an idea, please let me know!

Ill be updating this thread as I go, feel free to comment!

 

[zapwizard]

Nice 3D model so far.

Have you seen my Fallout Dosimeter project? I use a hall effect sensor as to provide a faux Geiger counter mode.
All you need is a hall effect sensor with analog or digital output that is proportional to the magnetic field. Then I generate a random click with a interval that is influenced by the magnet strength. It works great for cosplay as you can carry a magnet that is "radioactive", a bit easier to show than wifi strength. The hall effect sensors a simple through-hole parts and very easy to read on a microcontroller.
(Videos on page 3 showing the magnet sensor idea)

My design also uses a tiny air-core motor the size of a dime. They cost $25, but fit almost anywhere. I have code on driving them in my Radiation Kind Radio project.

 

[SpartaWorkshop]

Nice 3D model so far.

Have you seen my Fallout Dosimeter project? I use a hall effect sensor as to provide a faux Geiger counter mode.
All you need is a hall effect sensor with analog or digital output that is proportional to the magnetic field. Then I generate a random click with a interval that is influenced by the magnet strength. It works great for cosplay as you can carry a magnet that is "radioactive", a bit easier to show than wifi strength. The hall effect sensors a simple through-hole parts and very easy to read on a microcontroller.
(Videos on page 3 showing the magnet sensor idea)

My design also uses a tiny air-core motor the size of a dime. They cost $25, but fit almost anywhere. I have code on driving them in my Radiation Kind Radio project.

Thanks! I ended up buying a pack of x27 168 steppers and Ill see about using them. My only issue is that I dont have a lot of experience with coding on arduino and if possible Id like to have everything work in an analog way. Speaking of, your Fallout Dosimeter looks phenomenal! I might use your method to make mine work.

Sorry it took me so long to reply.

 

[zapwizard]

I tried using a 168 stepper earlier in my Radiation King Radio project. (If you need a 3D model of one I think I found a good version on Grabcad under "gauge motor")

The reason I didn't end up using it was that I found, even with half-stepping, the needle moves in very discrete steps, sort of like the second hand on a cheap quartz watch. They look great when moving between two values in a fast sweep, but not so good when trying to dial in a small values. If you are going to just make the needle jump or move when a geiger hit happens it probably will be fine.

If you decide to go with an Air Core motor: I have already done the Air Core motor control on the Dosimeter using Arduino C++. My current code for the Dosimeter is here. If you know Python already, take a look a Circuitpython. It isn't as power efficient as an Arduino, but much easier to program. I may convert the whole Dosimeter over for a RP2040 chip when I spin the project back up. I also would change the motor driver to the TB6612. (It has separate PWM and direction controls needed for air core motors)

FYI, I also seriously looked into making this and other Metro props myself, but I already have plenty of Fallout stuff to finish.

 

[SpartaWorkshop]

I tried using a 168 stepper earlier in my Radiation King Radio project. (If you need a 3D model of one I think I found a good version on Grabcad under "gauge motor")

The reason I didn't end up using it was that I found, even with half-stepping, the needle moves in very discrete steps, sort of like the second hand on a cheap quartz watch. They look great when moving between two values in a fast sweep, but not so good when trying to dial in a small values. If you are going to just make the needle jump or move when a geiger hit happens it probably will be fine.

If you decide to go with an Air Core motor: I have already done the Air Core motor control on the Dosimeter using Arduino C++. My current code for the Dosimeter is here. If you know Python already, take a look a Circuitpython. It isn't as power efficient as an Arduino, but much easier to program. I may convert the whole Dosimeter over for a RP2040 chip when I spin the project back up. I also would change the motor driver to the TB6612. (It has separate PWM and direction controls needed for air core motors)

FYI, I also seriously looked into making this and other Metro props myself, but I already have plenty of Fallout stuff to finish.

Good to know, thanks for the info! I dug into this a bit more and I found out that I can use the servo directly with the esp8266 which might make sourcing parts a lot easier. Now to find a small enough servo... Ahh ideas, ideas.

Regarding Metro props, I recommend using MetroEx which can be found on ModDB. It can view and even export the assets from the game if you ever need to get the model right. Been in that rabbit hole for a long time now lol. I was also thinking of revisiting the hand crank charger, but thats a topic for another time.

 

[SpartaWorkshop]

Im finally satisfied enough to say that the model is finally done and up on my etsy store. Has plenty of space to acomodate an arduino, a battery, and other things to make this thing function. Im also uploading the original game model. Make sure to scale it up x826.

 

[zapwizard]

Is the 3D model STL or STEP? I would want to add the switch and light details as you had earlier (But to match actual parts)