this post was submitted on 08 Jun 2026
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A lot of them have selectable voltage/power levels as a "feature", which is easier to do via a mcu PWM controll than discrete electronics.
yeah it's more efficient this way but all you need is ne555 + mosfet tho? still no need for it to be turing complete
A search in Digipart shows the cheapest price of this microcontroller as $0.10 whilst the cheapest price of the NE555 is $0.13
It really is THAT ridiculous.
not what i have expected tbh
Yeah, it doesn't make much since if you think in terms of how many transistors are needed to implement each of them as the microcontroller probably uses hundreds of thousands more transistors than a 555.
That said, given reasonably recent processes die size for both are probably pretty close (I reckon most of the size of a modern 555 die would be the points to place the wires to the package) and with pretty similar yields (pretty close to 100%)
I wouldn't be surprised if the reason has something to do with economies of scale since a cheap microcontroller can pretty much be used for the same things as a 555 and a whole lot more than that, so it makes sense more of the former are manufactured than of the latter, plus I bet the process generation used in making the microcontroller is probably more recent and hence one where there are more fabs operating. This latter reason would also explain why this more recent 32-bit microcontroller is actually cheaper than older 8-bit ones with less built-in memory and fewer peripherals (such as the ATTiny ones).
There are really cheap mcus that need maybe one capacitor if even that. It is cheaper, easier and more flexible than the multiple components required to configure an NE555.
Yes, but think about it like you're a Chinese manufacturing engineer with only basic electronics education. You COULD do that design, build out the pcb, custom tool it to fit your plastic housing, etc etc.... Or you could go to the manufacturer down the street who already makes pre designed voltage reg MCU's on a board and spend like, 20 minutes in an IDE to code the specific voltage levels and button presses.
When production volume and turnaround time is the only things that matter in this shovel waste crap, "wasting" silicon is less expensive financially than building out the optimal solution.
Designing a board to run a microcontroller like that is actually pretty simple.
I've done it for fun with a couple similar microcontrollers, and whilst I'm an EE by training I don't do it professionally plus my training is from before embedded system, so I count as a Junior EE for that.
I'm pretty sure that even a freshly graduate Chinese EE can even on their own figure out the general recipe for integrating something this (following the datasheet, add crystal + load caps, plus about 1 caps each power pin for power filtering plus 1 global power filtering cap, plus possibly a pull-down/up resistor on the RESET pin) in a week or two and then for subsequent projects it will be feasible to do it in a few days.
Really, there's other shit in there (say, battery management) that's more work to figure out than how to add and place the parts for an entry level ARM microcontroller to work.
my guess would be it's a parts commonality thing, it's not hard to make it the old way, there are datasheets for it too. sure you could probably make tiny and cheaper (30x10mm? maybe smaller) analog board with two chips and mosfet working as pwm controller and current limiter, but it'll have different passives for different battery sizes and heater powers. or you could make one design with optional usb port that you might just not solder on, and depending on model you just put different firmware inside
The old way is actually the analog style you've mentioned, but that was the very early days of ecigs well before they became mass market, the cottage industry modding scene had no hope of creating sophisticated microcontrollers and the charger wasn't even USB, it was a DC jack & plug. Lavatube was the first time we had that kind of microcontroller regulation & then the DNA15 and DNA20 came out, got cloned by China and that changed the game forever.
The problem with the older way is consumers understand watts alone as a relatively consistent measurement of power much better than they would the relation between voltage, resistance & current draw. They didn't want to learn Ohm 's Law back then and wouldn't want to know about it now. Microcontrollers simplified that massively.
With the economy of scale, it is probably cheaper to just drop a microcontroller in products
I was just thinking that yeah again all it needs is some basic components. Like how a light bulb or fan might have multiple power settings but I don't expect them to be able to run doom.
Thanks for the interesting read. Real nifty little timing/switching circuit!
it's kinda dogshit but for this application it (cmos version) would be good enough. or better than that, there are dedicated pwm signal generators. i meant this thing in terms of complexity needed
It was a good insight into how the lightbulb dimming tech of the 80s/90s worked. Also why the dimmer switches back then were so dangerous with the capacitor likely just a few mm's away from the light switch which might not have been properly wired because UK homes back then didn't run a neutral back from the switch, but daisy-chained the switch and the bulb together and then ran the neutral back from the bulb