Electrical – Routing power and HDMI signal into usb type-c for DIY computer monitor

diyhdmimonitorusb-cusb-pd

I am starting a project to build a DIY monitor. I have a spare lcd panel (model # LP156WF6) taken out of a laptop. I plan on buying a controller board for it and building it into a homemade enclosure. The controller board has an HDMI input and a 12V/4A barrel connector for powering the display. I would like to wire both the HDMI port and the barrel connector into the same USB Type-C plug and use the same USB Type-C cable to power the monitor and send it its signal from the thunderbolt port on my laptop. Is this even possible? I know HDMI over USB Type-C protocols have existed for a while now, so I imagine buying a USB Type-C pinout PCB and soldering a split HDMI cable to it should be relatively simple as long as I can find the wiring diagram. For the power, is it possible to simply wire a small power regulation board in-between the barrel connector and the Type-C pinout? It seems there are many products out there that support power and signal through the same Type-C cable, so this seems possible, but I'm afraid I'm greatly oversimplifying the procedure. I would greatly appreciate any advice anyone out there may have on the subject.

Best Answer

I know HDMI over USB Type-C protocols have existed for a while now, so I imagine buying a USB Type-C pinout PCB and soldering a split HDMI cable to it should be relatively simple as long as I can find the wiring diagram. For the power, is it possible to simply wire a small power regulation board in-between the barrel connector and the Type-C pinout?

so you can very cheaply make type-c to HDMI adapters

In addition to what Sam said about some ports and cables and other things, this would be an enterprise-level effort of two-three engineer-year long, for seasoned engineers. Even if your host laptop does have the Alt-DP/HDMI functionality (most recent laptops with USB Type-C ports do), your monitor must implement full-scale Power Delivery functionality, because engagement into Alt-DP mode can happen exclusively by means of heavy exchange of special class of PD messages, not counting for negotiating for right power contract. So "soldering a split HDMI cable" would be the least of technical concerns (except careful impedance matching of differential transmission line pairs is you want any decent display resolution).

Even if you get a correct interface IC (something from RealTek like RTD2556UT or else) and passes their volume requirement to be able to get any readable documentation, you will need to program these chips with properly formatted VDMs (vendor-defined messages) with right data content. Given the "greatly oversimplifying" prerequisite level of this question, simply forget about this. Your best bet for making a DIY Type-C monitor is to buy a ready-to-go "DIY controller kit, something like this one from Aliexpress:

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