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
Jump in the discussion.
No email address required.
Notes -
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.
At least they have counting down to a science:
3.0,3.1 Gen 1, 3.2 Gen1x1 (A SuperSpeed, B SuperSpeed, Micro-A SuperSpeed, Micro-AB SuperSpeed, Micro-B SuperSpeed)3.1 Gen 2, 3.2 Gen 2x1 (A SuperSpeed, B SuperSpeed, ... , Type-C)3.2, 3.2 Gen 2x2 (Type-C)More options
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