Sunday, January 1, 2017

Taken by a Strange Mood, Part 1

About two or three weeks ago I was taken by a strange mood.  We had our annual Christmas party, and I decided "wouldn't it be great if I could have movies in the back of the house as well as in the front."

Westinghouse 32" TV.  Collecting Dust.
We have this old 32 inch, 1366x768 Westinghouse LCD TV.  It used to be our primary TV (and was our very first flat panel HD television).  It doesn't even have HDMI ports, it's that old.  It served us well in its prime, but it has since been replaced by a 47" LCD (which was struck by lightning) which was replaced by a 55" Sony Bravia (the old version that weighs like 80 lbs and is 6 inches thick).  When we got the Sony, the Westinghouse became the bedroom TV, where it served admirably until about 2 years ago, when I wanted a chromecast for the bedroom.  Since it didn't have HDMI ports, I ended up buying another TV (42" RCA, I think), and so the old reliable Westinghouse was put in a back room to someday be used for something, probably.  I got my spare Raspberry Pi out, connected it to the TV's DVI out, with RCA audio, and burnt an embedded PLEX image to a spare SD card.  It booted, but the PLEX image did not know how to handle 1366x768 properly. Christmas party TV was a bust.  But there would be other parties.

Then, I got a brilliant idea!  Why don't I use a raspberry pi to turn it into a smart TV.  And not just a smart TV, but a retro game playing, plex movie watching smart TV.  It might work.  It could work.  And after I checked out the back of the thing, I might even be able to mount the Pi INSIDE the TV.  MWAHAHAHAHAHAHA!  Did I mention it was a strange mood?  I wonder if other engineers get these.

I took my existing RPi that I use for my backup server out of its case and opened up the TV, just to size it up.

Low and behold, not only was there space for the Pi to sit, but it looks like there was an entire area of this particular TV PCB that was unused (probably for a model with more features).  Now that I look at the pinouts in this area, it looks like it might have been a SCART input, or something similar.  You know, one of those TV connections that nobody knows about unless they work in media and television.  This is where I checked to see if the pi would fit.  Spoiler warning.  It did.  The next thing I needed to do to make this viable was find me a 5V power source inside the TV that I could power my raspberry pi off of.  I checked numerous plugs and connectors, and found several 5V spots.  Problem was, evertime I checked across them, the TV would shut down after a moment.  These were no good.  I then took a look at the power supply, and what to my wondering eyes appeared, but an unused, 4 pin connector.  I got my voltmeter out and read across the pins.  Two of them were ground.  Two of them were 12V.  But they didn't cause a TV shutdown when I read across them.  If I could just get a voltage downverter, I could connect here.  If only there was something you could buy that took a 12V input, and output 5V for charging a cell phone... like... a car charger... TO THE INTERNET!!!!!

The strange mood was in full swing now.  I was powerless to resist this new mania.  I found the perfect device here. Only problem was it had the wrong kind of USB plug on one end.  No matter.  I have a soldering iron and spare micro-usb cables all over the place.  The other problem was I had no idea what kind of plug that was.  Fortunately, the nice folks at the Adafruit forums came to the rescue.  I got on the amazon and ordered this, a Raspberry Pi 3, along with a clear plastic case.  The USB and Ethernet ports would face out of the TV chassis just below the AV1 input.  The trouble with this is that the micro-sd card is in the opposite side of the pi, and would be facing the inside of the TV chassis, completely inaccessible without opening the TV up.  I really didn't want to open the TV every time I wanted to try a new Pi image.  I wonder if they make Micro-SD Card Ribbon Cables?  They do.

Two questions remained.  How did I want to hook up the AV from the pi, and how was I going to get it all to stick firmly inside the TV chassis.  After much deliberation, and the bad DVI experience I had before, I decided to just use the Pi's AV out and connect to the AV1 input on the TV.  I kicked around the idea of wiring it directly, but ultimately decided to just use a cable, run it outside of the chassis, and into the inputs on the outside.  This would allow me unplug if I ever wanted to use the AV port for something else in the future.

As for how I would stick it all in there without worry, I decided to go with JB-Weld epoxy.  I may ultimately regret going with such a permanent solution, and it did make a few future mods more difficult.  But I won't have to worry about this stuff falling out of the TV ever.  And I mean EVER.  Next time, I'll show you how it all came together.