I picked up a Middle Earth a few months back and decided to rework it with a cobrapin controller. I promised myself I wouldn't do a pinside topic until I had a flipping machine, and...well, I hit that(mostly). So, an overview.
It started with a stock Middle Earth that wasn't booting.
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Some links:
Mission Pinball Framework: https://missionpinball.org/
Cobrapin: https://pinballmakers.com/wiki/index.php?title=CobraPin
Middle Earth Configuration: https://github.com/mikelatiolais/middle_earth

I started with switches. I cut the zip ties to the harness and started tracing wires. And here was the first real mistake. I should have disconnected the entire harness and split it up into sections(switches, solenoids, GI, inserts). Instead, I left it on the playfield and just worked around everything.

That took quite a while. The schematics, of course, only give you an overview of the electrical connections. For the real world wiring, you have to trace everything out. Since ME didn't use a switch matrix and they all shared grounds, I had to split them into groups and then cut up the ground to minimize how much I needed to rewire. You have to take into account things like matching autofire coils with switches on the same microcontroller, which made some of the wiring more complex that it needed to be. Also, there was a set of 10pt switches which were all chained together. Thus, that ground had to traverse the whole playfield.

After that, it was time to wire the solenoids. Or, if you know me, make a mistake and burn a mosfet out.
Once I got my initial mistake fixed, I was able to get all of the solenoids working. Due to the number of switches, I ended up using a cobrapin satellite board. This gave me more switches, but now required that I feed the flippers from there(autofire has to match the microcontroller). I bolted everything to a board to create the control system at this point.

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Now, came the new lamps and GI. I had hacked out all of the insert lamps....and accidentally some of the GI. Oops. I started with the inserts. I had some RGB lamp boards on hand(https://github.com/jhpieper/pin-led) and used those. One nice thing about the cobrapin controller is that I could solder a new LED on and plug it in to test. It would glow a nice low blue.

Then, it was time for the lamp testing. I created a simple light show for the attract mode.

After getting that going, I cobbled together a new GI harness and replaced all of the lamps with LEDs. All lamps are now running from the beefy 5v supply.

Next, it was time to start setting up the first modes, to test some basic things like autofire solenoids and the music. This is NOT the final music for the game.

My basic TODO list at this point:
1) Mount the new display in the apron(I am using a 6.5" LCD)
2) Finish the cabinet rewiring
3) Set up the amp and new speakers
4) Setup the base mode and dial in the solenoid responses
5) Cut a new apron with new art
With any luck, I'll be showing off a running game within the week.

Oh, and some initial thanks.
JethroP for the game
CodHollandaise for inestimable help in wiring and brainstorming
cobra18t for help getting the wiring figured out

Cobbling together a mount for the apron display.

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Installed my wooden monitor in the apron area. Need to run power to it.
Bolted the pc to the board and added a buck converter to pull 12v from the 36v supply for the monitor.
Time to start wiring the cabinet.

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And it works well. Cute little display. The current power connector is temporary. Just need to set up the system to auto run mpf and hide the mouse.

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1) Mount the new display in the apron(I am using a 6.5" LCD) - Done
2) Finish the cabinet rewiring
3) Set up the amp and new speakers
4) Setup the base mode and dial in the solenoid responses
5) Cut a new apron with new art

Tested the amp today. Works well. Need to cut a new hole for a speaker in the bottom of the cabinet. I think I might make a topper for a couple of speakers as well.

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Good catch. Yes, I was debating about putting an OPP power board there, since I have one handy. But, your solution is cleaner. Thanks!

Should both fuses be identical, since there is nothing else being powered by bank A?

So, running the satellite from Bank A presents another problem, @cobra18t. Currently, B & C are connected to the playfield. I would need to add a connector between the 36v on the Satellite board and the playfield(since 5v and ground for the Satellite are still connected directly). I'm not sure I want another connector sitting between 36v and the flippers. I guess I could pull 5v and ground from the gi on the playfield.

The existing banks are tied to playfield solenoids. Connecting the third bank to the satellite board means tying its power connector to that connector(attached to the playfield) and to the 5v and ground that the satellite board is already wired to. Not a big deal. I can either put a disconnect on the third bank wire or remember that I have to disconnect the direct 5v and ground if I pull the playfield.

I went ahead and connected it. I'll reattach the grounds and 5v when I'm installing the playfield.

Added 4 service buttons, and got all of the other cabinet switches connected.
Getting closer.

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Powered up from the switch for the first time.

Controller and power board installed. I guess it's time to install the playfield...

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Some days it doesn't pay to get out of bed.
I think I had a short that took out the boards. I'm assuming it was 36v to 5v. Might have cooked the chromebox too.

Didn't kill as much as I thought.

First game!

So, it turns out that I had plugged a connector in the wrong spot and sent 36v on the 5v system. It killed the 36v power supply and the original cobrapin board. Luckily, I had a 48v supply and a spare cobrapin.
However, the biggest loss was the lamps. It looks like I'll be resoldering most, if not all, of those.
Could be worse.
Implemented a ball save tonight. Working on the software for a bit.
Still need to cut a hole for the new speaker.

That is coming. Probably going to use cardboard tomorrow, and a piece of acrylic permanently.

A pinsider enjoying a game while I watch.

Got time this afternoon to solder the wiring for the service buttons. Need to decide if I can shoehorn a door switch on this thing.

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Decided on no door switch.
Replaced the old flipper switches with new switches. A lot more responsive and no "machine gunning" anymore.
Started replacing each of the RGB leds.

Got the bar scoring added in, along with the high score mode. I think I track high scores and loops.

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I also got the service mode working. Very nice work on the part of the MPF team on implementing these built in modes. It's pretty painless.
I am redoing the insert lamps. I'm going to test some diffused LEDs in places, as well as move from soldered wiring to connectors. Ordered a bunch of premade connectors from China, so we'll see how those work out.

New lamp boards are in. I've also started building some diffused led versions for some inserts.

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Thanks!

The bluepills won't boot when in the board. They do, however, boot in another board. I think it's the level shifters, and I have some on order to see if I can fix it.

Hmmm, good idea. That is one drawback to using these little chromeboxes. The button is not easy to get to, and requires that you disassemble the entire device. I need to get on that, since I had planned to install one of Scott Danesi's power controllers.

Playing with some open source sound effects.
Music is nice, but I need to replace it.

I got one of the special modes set up today. When you complete a drop target bank, you have a few seconds to hit the target behind them, which is worth 2000 points until it resets. It also has a sound which plays until the reset.

Bunch of little updates.
The main theme starts and stops when the mode starts and ends. It also cuts out the intro of the music, so it sounds better. Neither is particularly important, since this is placeholder music, but still...
The ball save now behaves correctly. It was starting on ball launch, which meant you could eat up your ball save while the ball sat in the shooter lane. Now, it starts on the playfield_active state.
Fixed the 10pt switch scoring.

I also got the original cobrapin board booting again. I think that there is still something screwy with the 5v system, so this one won't ever be driving RGB lamps again, but that's ok.

Without other modes, you mostly shoot for the drops, and getting control again fast enough to score on the 2k shot is a challenge. I think I'm going to work on a timed spinner mode next.

More little changes. I need to get someone over to film a full game now.
- Changed the font to a green monochrome CRT style to mimic 70s/80s terminals
- Fixed some bugs with the drop modes
- Added more sounds(I think all of the switches have an associated sound now)
- Added some initial shots in the base mode to begin an attack mode

Still deciding on how to enter into an attack mode. I'd like to have a way to pick your modes, but it's problematic, given that I have no way to trap the ball without adding some sort of physical stop. Given the limited number of shots, I don't want to have something like "do X 20 times to activate the mode where you do X 20 more times to finish."

I have contemplated awarding a random mode upon finishing the mode activation shot. Right now, I'm thinking 3 attack modes, then one frantic escape mode. After that, activating the modes takes more hits. I'd love a multiball, but one of the rules I gave myself on this build is not to change the physical elements of the playfield beyond what the new controller required. I really wish that there was another rollover in the loop, for example, and adding a locking post on the loop wouldn't be terribly hard.

It sounds great with the amplifier!

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Added some voices to the system.