World’s Smallest Blinky, Now Even Smaller

Here at Hackaday, it’s a pretty safe bet that putting “World’s smallest” in the title of an article will instantly attract comments claiming that someone else built a far smaller version of the same thing. But that’s OK, because if there’s something smaller than this nearly microscopic LED blinky build, we definitely want to know about it.

The reason behind [Mike Roller]’s build is simple: he wanted to build something smaller than the previous smallest blinky. The 3.2-mm x 2.5-mm footprint of that effort is a tough act to follow, but technology has advanced somewhat in the last seven years, and [Mike] took advantage of that by basing his design on an ATtiny20 microcontroller in a WLCSP package and an 0201 LED, along with a current-limiting resistor and a decoupling capacitor. Powering the project is a 220-μF tantalum capacitor, which at a relatively whopping 3.2 mm x 1.6 mm determines the size of the PCB, which [Mike] insisted on using.

Assembling the project was challenging, to say the least. [Mike] originally tried a laboratory hot plate to reflow the board, but when the magnetic stirrer played havoc with the parts, he switched to a hot-air rework station with a very low airflow. Programming the microcontroller almost seemed like it was more of a challenge; when the pogo pins he was planning to use proved too large for the job he tacked leads made from 38-gauge magnet wire to the board with the aid of a micro hot air tool.

After building version one, [Mike] realized that even smaller components were available, so there’s now a 2.4 mm x 1.5 mm version using an 01005 LED. We suspect there’ll be a version 3.0 soon, though — he mentions that the new TI ultra-small microcontrollers weren’t available yet when he pulled this off, and no doubt he’ll want to take a stab at this again.

21 thoughts on “World’s Smallest Blinky, Now Even Smaller

    1. No, because even if you can get a microchip small enough to travel through a needle it cannot do anything useful (or anything at all) once in the body. Just because a microchip is tiny does not mean that the necesary equipment to power it (a coin cell or such) is also small miniaturisable so as to fit within a needle, nor is the equipment it would need to be able to communicate with the outside world (RFID coil or such, these ofcourse could provide power too instead of a coin cell, but again there’ye way too big). So no, there are no microchips in vaccines, that would be a waste of microchips, they’d not be able to do anything more inside the body that they could when sitting in factory fresh SMD reels. For full disclosure I didn’t take it, but only because I had already acquired natural immunity to the disease in question, and because not taking it was a good way to protest against the immense collateral damage of lockdowns.

      This whole discusion does raise one very relevant point about this very talented project, given that this LED blinky is far smaller than the equipment (battery…) it would need to power it, why make it so small. I’d be interested in hearing Mike’s reasoning, although because-I-wanted-to-try is always a great reason, for why he’s made a board which will need a power source vastly larger than it is. Thanks

    1. I was wondering what the limit on “running” was. Like if the PCB mas fabbed such that the board itself could be used as a capacitor like on chip FAB. I’m certain that would hold some electricity. Maybe enough to power the ATTINY for a microsecond. Does that count?

  1. I have to ask one very relevant point about this very talented project, given that this LED blinky is far smaller than the equipment (battery…) it would need to power it, why make it so small. I’d be interested in hearing Mike’s reasoning, although because-I-wanted-to-try is always a great reason, for why he’s made a board which will need a power source vastly larger than it is. Thanks

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