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Project Notes

#621 KübelMagic

A walnut, Brengun 1:144 Kübelwagen and a miniaturised SMD version of a BJT oscillator - and with a bit of practice, some close-up model magic.


Here’s a quick demo..



I picked up this pair of 1:144 Kübelwagen on impulse when buying a PE kit from Hauler/Brengun.


They sat on the shelf for some time. I think it was seeing some artwork for Episode 21 “Going small” of the just making conversation podcast that inspired me to wonder if I could use the two vehicles with a bit of sleight of hand…

I asked James & Malcolm from the podcast about the artwork and they clued me in: The original model was by Mike Zax. He has a video covering the build:


The vehicle he used was a 1:150 Ford GPA Amphibious Jeep/Seep, rescaled from a 1:87 R & P Models paper kit.

Electronic Circuit Design

In the “exploded” view, I have some fast flashing LEDs to intimate a blazing fire. I’m using a simple BJT oscillator, but with SMD components and a 3V battery holder to try and conceal it within the shell of a walnut.

The circuit uses a tilt-switch to turn on the circuit when up the “right” way.

I verified this on a breadboard first in order to finalise the component selection. I settled on 1µF capacitors and 100kΩ resistors for the RC circuit, leading to a relatively fast flash of around 7.2 Hz.



NB: same basic circuit as covered in LEAP#049 BJT RC Oscillator

Electronics Build

I used a small piece of perfboard for mounting the SMD version of the circuit as compactly as I could.

build01a build01b

Model Construction

The Brengun kit is very nice - resin with PE and decals for quite a detailed model at 1:144. I think the front door handles are back-to-front however, ended up fixing this.

build02a build02b

I grabbed a handful of Vallejo Model Color for the paint. Didn’t record all the paints used…

build02c build02d

The Shell

Just a Walnut shell, carefully split with a piece of plasticard as a ground plane between the two halves.

In one half we have a “peaceful” scene with a tree and some kind of bowser (actually it is the tilt switch)


With the Kübelwagen in place.

build03b build03c build03d

On the reverse, we have the destroyed Kübelwagen with a plume of smoke and the LEDs flickering like flames. Don’t know exectly what happened, but it was pretty devastating!


Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.