Report
I’ve got HDMI output working from the Rasppi without a camera. As per the usual, everything that could go wrong did go wrong, and I spent an unfair amount of time troubleshooting. The display was meant to arrive today (March 22) so in theory, if it did, I’ll get word about it from the receiving office on Monday. I’ve got access to a device that takes AV input, so if it isn’t here by then I’ll put in an order for an AV cable, cut an end off it, and solder the free wires directly to the Rasppi’s test pads. Then when I need to hook it up to the final output I can just cut the cable again to get necessary length and bare the other end of the wires. I might end up with a little more insulation than I was expecting, but really I can’t imagine it’ll be anything more than marginal.
I’ve been working today (and will return to working on it after I finish this writeup) on getting the Rasppis to be able to talk to each other over I2C. In theory it’s possible, but since their default settings are strongly weighted toward being I2C masters getting one to act as a slave is proving inconvenient (as per, again, the usual), though every document and forum post I’ve found more recent than 2013 is holding that the hardware is capable of it and the software exists to make it happen. Worst case I resort to using the GPIOs as GPIOs and just manually run a barebones protocol for the communication, which I think should be fine, considering we are not running more than like, a single byte a handful of times a second across the line.
Edit, two hours later: it works!!
Currently the slave device is running C code that consists of an infinite loop constantly monitoring for messages. I’d like to swap this out for Python (for language consistency) that does event monitoring, to reduce the loaded power consumption. The wires between my two boards are NOT soldered in right now, which feels… suboptimal, but hey, whatever works. Or works sometimes, I guess.
Progress Schedule
I’ll do my best to get them talking to each other tonight; if I can’t, the display arriving becomes my real hard deadline. They are talking.
I also really actually need to order the power supply this week. It is still very much on my radar.
Next Week’s Deliverables
If I can catch just a teeny tiny bit of luck at least one of my displays will have actually arrived this weekend and I can pry it apart next week. Then I’ll only be sans the power supply for things I have to order, and can put all of the things together if only powered by my laptop.