A really, really tiny microcontroller board


Here’s something very cool from the wonderful world of Adafruit: The Trinket, an Arduino compatible microcontroller platform that’s not only small enough to fit in your pocket, it’s small enough to lose in your pocket.

Like the similarly specced Digispark, the Trinket features an ATTiny85 microcontroller with 5 IO pins. Unlike the Digispark, the Trinket is a bit more substantial, featuring 3.3 and 5 Volt regulators along with a real USB port and mounting holes. As this is based on the ‘tiny85, it’s possible to connect this up to I2C and SPI sensors and peripherals

One thing to note about the Trinket is the fact that it’s so cheap. Either version of the Trinket goes for about $8, inexpensive enough to simply leave in a project when you’re done with it. Given the cool stuff we’ve already seen created with the Digispark, including a homebrew stepper motor and an Internet meme and lame pun assessment tool, we can’t wait to see what’s made with the Trinket,


  1. TBO says:

    Too bad they don’t use a four-connection standard USB plug on the PCB directly, instead of using the mini USB plug. That would be cool to be able to plug the board in directly, no cables needed. They could probably have traces on one side for that, and the mini plug on the other, so that you could solder the mini plug if needed, or leave it off and just use the direct plugin for a small savings.

    • Caleb Kraft says:

      The integrated male plug is nice… until you actually put your board into a circuit. Then having a cable plug on it becomes much more important.

      • notdave says:

        dont really see how that matters, use a usb extender cable? sure mini usb cables are more common, but just because it would have a male connector you are forced to plug it directly into a usb port.

    • Frank says:

      Those PCB plugs require a much thicker material

      Also the exposed traces are more of a liability sometimes

    • Phillip says:

      You’re right, that would have been nice. One of the advantages of the 5v tiny85 at 16MHz is that it can run software USB. If this board had a male USB connector on-board, it would be perfect for creating all sorts of USB peripherals.

      Then again, I guess it would need a switch to put it into programming mode, and that might make the board a bit larger.

    • tekkieneet says:

      I would rather use a solder on plug. They are only $1.70 for 10 on DX.

      The uP pins are not exposed as bare PCB, so you would reduce the chance
      of ESD damages. If you don’t want USB for a particular project, the
      connector can be removed (so smaller) and the I/O pads reused.

      It is better to glue plastic or other filler material on back side of
      PCB to make it thicker than to use thick solder over the tracks.

  2. JTR says:

    Oh Damn. Just beaten to the name “Trinket.” Well, who knows, after my death my small pilot run of PIC 16F1459 boards may be collector items.

    • Greenaum says:

      Depends how long you take to die. The road from valuable hi-tech doodad to antique spends a lot of time passing through “junk”. So if you could fix it to die either about 20 years ago, or in another 100, you might be on to a winner.

      Reminds me of the 30-pin SIMMS on sale for a quid each with keyring chains attached to them, at a computer market some years ago. He had plenty more than he could sell. Thinking about when I paid 50 quid for 2x1MB , not so long previously, made me wish for a time machine.

      It’s interesting how Moore’s Law seems to have died off, and nobody’s really started panicking over it. The progress at squeezing more cores onto a chip isn’t proceeding along as fast as the MHz race used to. All the progress now is taking place at the very-low-power end with ARM chips.

      • ColdTurkey says:

        Hahahaha! That first paragraph tickled me rosy!

        Interesting point though about Moore’s Law, years ago that seemed to be the main focus for pushing new clock speeds out of CPU’s, now it’s about low power and high efficiency. It’s a shame Atari aren’t making shit like they used to. Some true genius happened to make what we know today.

  3. Dougal says:

    Some notes on Trinket vs Digispark:

    * The Digispark has 6 I/O pins (it uses fuse settings that override the RST pin).
    * The micronucleus bootloader on the Digispark comes in at just under 2K. The Trinket bootloader is around 3k (probably due to the USBtinyISP stuff). When you only have 8K of program mem to start with, that 1K can make a difference.
    * The Digispark regulator can supply 500mA, but it seems that the Trinket only gets about 150mA.
    * Top input voltage for Trinket is 16V, for Digispark it’s 24V

    On the other hand, some people might prefer the form factor of the Trinket — it’s slightly narrower and longer, and the parallel GPIO rails are more breadboard friendly (the Digispark has an L-shaped arrangement of power and GPIO pins). Also, the USB socket on the board is a bit nicer than the Digispark’s circuit-board-as-USB-connector approach.

    Disclaimer: I’m a Digispark fan and Kickstarter backer. But I might get a few Trinkets, as well. :)

    • Johnbot says:

      The Trinket can also be programmed without unplugging it, and it doesn’t seem to have the 5-second boot time to check if it is being programmed (thought that is disable-able with the digispark, they do seem to have their trade-offs.)

    • TacticalNinja says:

      It’s amazing that despite you being a digispark fan, you gave no bias on the digispark versus the trinket. Unlike those arduino/ARM/PIC fanatics who’d kill other people who don’t agree on using what they “think” is the best platform to develop on.

      • It’s not up to me to decide which one might be better for someone else’s purposes. :)

        The Digispark was my first foray into Arduino (and rekindling my old electronics hobby).
        Compared to a “real” Arduino (i.e., an Uno, Mega, etc), it’s pretty limited. For me, the limits helped me focus on the essentials and learn one thing at a time. But just as I have many types of projects that I want to tinker with, I know there are many types of platforms to start from. I just see the Trinket as another “potential” for project platforms.

        Digispark vs Trinket vs [nano, teensy, femto, DIY, etc]? Nah, not “versus”. They all have their place. Same thing for Arduino vs. RasPi vs. Whatever. To each his own, and I want to try them all!

  4. Dougal says:

    Oops. Also meant to mention that some people might like the 3.3V version of the Trinket — the Digispark is normally 5V.

  5. Trui says:

    These little boards seem a perfect candidate for a QFN33 part. Smaller than SOIC, but tons more I/O.

  6. Indyaner says:

    I’m one of those guys who loves those small boards. Arduino Nano + Mini, Femtoduino and all those miniboards… I really have a huge heart for them.

  7. Beherith says:

    8$ is not a really good deal. I usually buy a couple of Arduino Nano clones, which are superior to this in every way, except size. The nano clones cost 8$ a pop and include a USB cable. I just dont even understand how one would pay 25$ for any arduino.

  8. vlad128 says:

    How does USB support work? AFAIK attiny doesn’t have hardware USB, am i wrong?

  9. Mithrandir says:

    Bam – out of stock. :\

  10. Joost says:

    I like the board. But is this kind of post the beginning of “hidden” advertising?

    • Johnbot says:

      But they’ve been doing this kind of post for a while now. It’s like Hack-a-Day and Adafruit are friends: Many of Adafruit’s endeavors are featured on Hack-a-Day and Adafruit started selling a Hack-a-Day iron-on badge (which was also featured on Hack-a-Day).

  11. Erik says:

    Weird – I was just pricing out a Arduino Micro yesterday for a little project I’d like to try, and this thing shows up today. Seems perfect for what I want to do (PWM on some LEDs.)

  12. Fungus says:

    Why bother? I can get two Pro Minis for the same price (they have a Mega328 and the PCB is only 2mm bigger). Either make it smaller or at least give me the ability to go into really low power mode (ie. a jumper or cuttable trace to disable the power LED and voltage regulator).

    • frank26080115 says:

      What if they need Trinket for prototyping to help them move on to a custom PCB with SMD parts later? That’s the entire point of a “development board”.

      One thing you’ll eventually learn is that there are 7 billion people on this planet and everybody has different needs. Never ask “why bother”, somebody will want it, even if you don’t.

  13. Squonk42 says:

    Check this one.

    No power LED/voltage regulator, just the bare thing…

    There is another one from the same guy, with PCB-etched USB or mini-USB connector.

  14. mle says:

    Is there any other small ucontroller like this with several pins maybe >40 pins ?

  15. supershwa says:

    I’ll probably grab one just to keep it around and save time if needed, but I already have a bunch of ATTiny85 ICs in a drawer.

  16. peeface says:

    Ugh, I got a trinket and I hate it. It supposedly has three PWMs but you need to do a lot of coding cobbled together from random tutorials from their site to get it to work. Even then, I never could get it to compile correctly and never got the third PWM to work. Seeing as how I got one for the sole purpose of controlling an RGB lamp (night light for a friend), it’s pretty much useless to me.

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