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  • Author Author: baldengineer
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NFTy GIFty Schematic Review (for a holiday ornament style PCB)

baldengineer
NFTy GIFty Schematic Review (for a holiday ornament style PCB)

For the 2022 Holiday Season, I'm designing an Ornament-Style PCB. (Last year I did a PCB Gift Box with LEDs.)

In short, it is a 1.8" TFT LCD connected to a Pi Pico (W). The idea is to display GIFs downloaded on the LCD. I've started on the initial PCB layout. I'm still toying with a few ideas there.

Why the name NFTy GIFty?

It is a bit of a joke on Non-Fungible Tokens (NTFs). Early on, a suggested use for an NFT was to claim ownership of a GIF. So, my idea is to have a way to display GIFs that were already freely available, yet someone decided to mint an NFT for them. The PCB Art design is going to feature a chain-link picture frame to represent the "blockchain."

This could be the world's first physical NFT Block Chain device. (Don't worry, I'm working on a Kickstarter and Indiegogo campaign in the background!)

Version 1 Schematic

For now, here is the current schematic. I'd like to hear any feedback, questions, or concerns. I tried to annotate the schematic with a few notes.

kicad schematic as an image

Alternative links

You can download a PDF or the entire KiCad project from GitHub.

FYI, I am live streaming this project if you want to follow along.

Thanks for taking a look!

  • in reply to dang74

    Agreed. Code is never my strongest aspect. I have found some GIF handling libraries which I am hoping will simplify the process. It should at least provide a starting point for someone better at software than me.

  • This is a pretty interesting project.  Even beyond the specific NFTy GIFty, which is clever by the way, this project can serve as a template for anyone wanting to make a display with slide show capabilities.

  • in reply to shabaz

    Facepalm. For some reason, I was thinking that the Pico handled that, but I remember the explanation you mentioned now. (at least it is now and not after I got the boards back...)

    I'm glad you pointed it out!

    Thanks.

  • Looking forward to seeing the project develop!

    I was wondering, what is U4, is that a typo, should it be a switch (e.g. SW4) instead of being labeled U4, or is it a power switch IC?

    image

    If it's a mechanical switch, then there could be a possibility of it being in the Vbatt position when the user has also plugged in the USB connector on the Pico, and in that case, VSYS may be at about 4.3-4.4V or so, from the USB power.
    To prevent that, the Pico datasheet suggests either a diode, or a MOSFET. I've been using a MOSFET so far for most Pico projects, like this (where VSW in this screenshot would be Vbatt in your project), which is just a slight elaboration on what the datasheet mentions (I added the R16 in the screenshot so it's in a known state, it might not be necessary but just-in-case, and R15 since the gate is so tiny, I wonder if it may accidentally damage it over time if I don't):

    image

  • in reply to wolfgangfriedrich

    Thanks !

    1. I should have noted that the 47R is a placeholder. My largest concern is how the backlight will perform with the 3.x supplies. But. I'm not adding a boost converter just for it. I have even considered just doing a 0ohm there and relying on the FET's multi-ohm Rds-On to act as the limiter.

    2. Good idea, I'll add some damping resistors. It will be fun to measure with a near-field probe with 22ohm and 0ohm just to see the difference.

    3. Fair enough. I do it as a shortcut when first drawing the schematic. It is an easy way to mark the GND pins while wiring up everything else, without the clutter of the GND symbol. It's also helpful in my next stage when I start moving the GPIO assignments around. That way, I don't accidentally label a GND pin with a signal. (Sometimes, I go back and replace them with a symbol once the PCB layout is done, but lately, I have been skipping that step.)

    4. Got it. I'll add a few more so the phase differences cancel them out.... somehow. Slight smile

    Thanks again for your help!