Tiny micro desktop smoke machine

Having to re-order more circuit boards gave me an opportunity to change a few things around; I needed to create a little more space to accommodate the new rectifier component, but it did give me a chance to make the whole thing a little slimmer and more streamlined.

As the micrcontroller was also vastly under-utilised for this single purpose, I added in some fancy LED control and a single, RGB LED.

Thanks to the automatic white balance and terrible autofocus on my camera phone, the effect isn’t as clear in the video as it is real life; but the single LED creates a half-decent flame/flickering effect.

I figured that anything that is going to have smoke coming out of it on the tabletop is likely to be simulating something on fire – so having an LED that looked like a flame effect just seemed like an obvious use of all those extra processing cycles that were going unused in the microcontroller.

So here’s the final design.

It’s still about 30mm high, but now only about 14mm wide. Small enough to cram inside a building – or even an model steam train!

I decided not to make the vape fluid container an integral part of the actual smoke machine – so long as there’s room for something under the coil, the actual size of the container can be left up to the user; I’ve tried 1ml, 2ml and even relatively large 6ml containers to hold the vape fluid.

You can 3d print your own juice containers, or use ready-made glass vials (as I found on the interwebs) or any little pot/jar.

So there it is – that’s about as small as I can get it. Part of me thinks that, with a little more time and effort, I might be able to shave the odd millimetre off, here and there. But that would require me to use smaller (phyiscally smaller) components. And smaller components usually can’t handle the relatively high currents required to get the coil up to temperature.

So I’m calling this one done.

In this final version of the device, there are a few things of note:

Because the incoming voltage passes through a rectifier, to ensure it’s always the “right way around” the full 12V isn’t available to the coil – this isn’t a bad thing really, since the full 12V caused the coil wire to get so hot it glowed red!

This latest version switches between “coil on” and “coil off” like a car indicator – it comes on for a number of seconds, then goes off for a number of seconds; this ensures that even if the coil were to be powered by the full 12V, it would never be on for more than a few seconds at a time.

Even when the coil is not powered, it retains its heat for a few seconds – so even though it’s off, the vape juice continues to vapourise. Before the smoke finishes, the coil turns back on and creates yet more – the overall effect isn’t that the smoke machine is turning on and off in bursts – more than the smoke “billows” in pulses.

Although the camera fails to pick it up, the integrated LED creates a warm flickering effect that simulates a flame, which makes it ideal for inside a building – either to simulate a bombed out building, or even something like a domestic fireside/hearth.