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ArjinFerman  Tinfoil Gigachad  1d ago (text post)   207 thread views

Tinker Tuesday for November 5, 2024

This thread is for anyone working on personal projects to share their progress, and hold themselves somewhat accountable to a group of peers.

Post your project, your progress from last week, and what you hope to accomplish this week.

If you want to be pinged with a reminder asking about your project, let me know, and I'll harass you each week until you cancel the service

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Trying to figure out how I can hack together a media device that meets the following requirements:

  1. Plugs into a TV via usb or hdmi without any additional power cable
  2. Automatically starts playing a video file that's stored on the device

Best I can figure is a fire stick or equivalent loaded with an app I found that will auto play video files, but those seem to require a power cable plugged into it. I thought about just using a USB stick with the file(s), but that would make the user navigate the file system and play it through the TV's media player - a bit more friction for the user than I'd like. An hdmi port doesn't supply enough power to run a raspberry pi so that idea went out.

Is this even possible?

I thought about just using a USB stick with the file(s), but that would make the user navigate the file system and play it through the TV's media player - a bit more friction for the user than I'd like.

Given this, the exact use case probably matters. What is the use case where the users can figure out the right HDMI port to select with their TV remote, but can't figure out how to play a video off a USB drive? Or plug in both HDMI and USB for that matter.

Do you also have control of the TV that will be installed? If it's a permanent instillation on a TV you select, you might be able to fined one where you can flip it to demo mode or some sort of auto play. In the former case I wonder if there is a way to overwrite the demo footage built into the TV. Then it should just play when the TV is powered.

For a mobile application, could a battery bank to power a fire stick or similar work? That would save the need to plug into the TV USB for power.

HDMI MHL gives more power, but the standard implementation is dumb, and it's not very commonly supported for televisions.

Chromecasts (and Intel Compute Sticks, and some Roku?) solve this by using USB power in and HMDI out. It's a little janky, but you can build something that looks like a single cable where both plugs go into the television. You're dependent on the television supporting the USB power spec properly, and some of the lower-end ones either fall under 250mA on USB or don't have USB out at all, but most large entertainment televisions today are usually better about it. Other downside is that while there's a lot of devices in this class, most of the common and cheap ones are designed as Apps First: requiring either WiFi access to the internet or serious fiddling to get to specific content.

That said, throwing your own together from prefab components isn't too nightmarish. The Microcenter-grade option is a Pi Zero (or Zero 2), which can do up to 1080p video (on local storage, in sane compression algorithms) without too much problem, and loading data onto a MicroSD card isn't too rough -- though trying to load a full media center like Kodi in can be sloooooow. If you want to go to 4k, things get a little more annoying. The mainstream Pis 4/5 can do it, but suck way too much power; the CM3 sticks need breakout boards and I wouldn't be confident about their 4k decoding. The Radxa 3E and 3W are supposed to be good for 4k decoding, but supply has been inconsistent at best.

That said, those all will have an extra cable involved, and worse still (excepting the CM3 breakout board) it's usually an annoying Micro/Mini/whateverthefuck HDMI rather than something you'd have in a parts bin. Even some of the more specialty western-focused shops like FriendlyElec don't seem to have a real specialized Compute Stick/Chromecast competitor.

Building your from scratch would be doable with the power budget -- hell, you might be able to get away with sub-50mA draw -- but it'd be pretty hefty call: HDMI interfaces aren't trivial, and since there aren't many good cheap 4k decoding SoCs you'd probably get to learn about power staging and memory differential signalling the hard way.

If you really don't care about resolution (or, uh, the FCC), analog TV signals are another option, and then you could just plug something into the wall in the same room. There's still a science project involved, but if you're willing to pay a bit it's not that much of a science project.

What about USB4? Theoretically, it should support PD in one direction and DP/HDMI in the other direction.

USB specifications are an absolute clusterfuck. USB4 does not mandate any level of PD support, USB-the-cable-spec requires only 500 mA at 5v, and devices that support USB4 don't have to guarantee DisplayPort Alt Mode (which runs almost all USB->DisplayPort and USB->HDMI interface; there is an HDMI Alt Mode spec but I have literally never seen anyone promising to use it, nevermind any actual products that use it) on every (or even any) interface.

If you were buying a specific television for this specific purpose, you might be able to get it to work, but at least from a quick google, I wouldn't want to bet on even that. Nearly everything I could find in a quick google was marketed as a monitor and capping out around 40". It's easier to find MHL televisions, despite the spec being nearly dead, than USB-DP televisions.

USB specifications are an absolute clusterfuck.

At least they have counting down to a science:

  • USB 1.0 (A, B)
  • USB 1.1 (A, B)
  • USB 2.0 (A, B, Mini-A, Mini-AB, Mini-B)
  • USB 2.0 Revised (A, B, Micro-A, Micro-AB, Micro-B)
  • USB 3.0, 3.1 Gen 1, 3.2 Gen1x1 (A SuperSpeed, B SuperSpeed, Micro-A SuperSpeed, Micro-AB SuperSpeed, Micro-B SuperSpeed)
  • USB 3.1 Gen 2, 3.2 Gen 2x1 (A SuperSpeed, B SuperSpeed, ... , Type-C)
  • USB 3.2, 3.2 Gen 2x2 (Type-C)
  • USB4 (Type-C)
  • USB4 2.0 (Type-C)

Day 5 of NaNoWriMo. Day 1 was surprisingly fluid, especially considering that I didn't start writing until getting home from work, and had only gotten about 4-5 hours' sleep the night before as a result of being a good Samaritan. Day 2 was torture, getting the words on the page was like pulling teeth. Days 3 and 4 have been pretty plain sailing. On the whole I'd say I'm enjoying the process so far. I crossed the 7k mark this morning - perhaps the part of the experience I'm most surprised by is how easily I've found it to write on the train during my commute.

I tried doing NaNoWriMo before, I think in 2021, but gave up literally on the first day as I had only the vaguest idea of what I wanted to write about. The difference in this case is that I've had a month's planning going into it, so at the outset I knew what had to happen when, the names of most of the major characters etc. This has made all the difference in the world in motivating me to keep writing.

How have you been doing @Southkraut?

Redot

So I had a some time this week and decided to give Redot another look. Turns out that their Twitter accunt has been hacked because of course it was, but other than that they seem to be chugging along. There's finally a build that runs on my distro of Linux out of the box, so I'm dusting off some of my old sandboxes, and going over the docs, because it's been a while since I did anything with Godot.

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