I think, with a 32U4 Pro Micro clone, I can support up to four controllers with all pins wired up. That's clock, latch and 3x data lines per controller, which is 20 in total, but I think I can make the latch pin common to all ports - that's the one that causes controllers to reload their states into their shift registers for reading.

I think the MVP for my adapter will be two ports - both the Advantage joystick and Four Score adapters have two plugs - but a four port variant should be possible.

Reading from a NES Four Score looks trivial.

For a regular controller, which is basically an 8-bit shift register, after strobing the latch pin, strobing the clock pin 8x will reveal its D-pad and button states, and you do the same again on the second port for the second controller.

The Four Score appears like a 16-bit register, so you flick the clock eight times to read player 1's pad, then another 8x to read 3. Then you do the same to port 2 to get players 2 and 4. https://www.nesdev.org/wiki/Four_player_adapters

The Hori 4 Players adapter (15-pin "Famicom Expansion" plug) looks identical to the Four Score in terms of protocol, and while nobody appears to have documented exactly what the NES Satellite does, I'd be very surprised if it did anything differently at all.

Satellites are also not particularly difficult or expensive to get, either. I foresee a new mini collection brewing... but I'll force myself to wait and validate my NES MAX pad working with my adapter before I start acquiring more hardware.

Here's my vision for the NES socket: a #3DPrinting frame for wires bent at a 90 degree angle to be pushed into, with one end pointing out into the socket for a plug to slide onto, the other out of the frame to go through holes in a PCB to be soldered down.

I will also make some sort of jig for precisely bending... some sort of wire. I know not to use anything galvanised as the fumes from soldering it is toxic, so my first attempt will be with 1mm copper jewellery wire - any other suggestions?

That settles it - the pins in a #NES controller socket are of 1mm thickness. This validates my measurement from the photo I saw.

This is with the current reproduction socket, of course; there is still the guy who measured his at 1.2mm (method unknown), and the other guy who made his own controller using sockets that took 1.3mm pins. It's possible the original hardware used thicker pins, but the 1mm jeweller's wire I bought on a whim seems to make a solid connection in this OG controller plug.

The pins in the socket itself are on a 4x4mm pitch, the two rows of pins that go to a circuit board seem to be intended to be 3mm apart.

The spring clips seem to need a 4mm hole. The centre line between the two clips seems to be 10mm from the centre of the nearest row of pins, and the clips themselves seem to be 20mm centre to centre.

Reverse-engineering stuff made to metric measurements is so much more pleasing than those made in old money. Japanese hardware just hits different.

It didn't escape me that 1mm pins are thicker than what I'm used to - if you buy typical 0.1" header pins, you'll get ~0.6mm square pins that perfectly fit the apparently-default 1mm through-holes.

I'm *fairly* confident 1mm round pins will fit into 1.1mm PCB holes, but I know for sure they'll fit the next size up in software which is 1.5mm. I can also set the holes to whatever diameter I want.

I need to order a board that's just different pin pitches and hole sizes to test parts on my desk.

And that's it - another Very Specific Adult Fingerpainting Adventure (or so it feels) on its way to manufacturing.

I've heard submarine warfare being described as weeks of sheer boredom punctuated by moments of extreme terror. Hobbyist electronics is similar - hours of hyperfocusing, interspersed by weeks of "aww, still in Memphis".

A quick test print with holes that are 1.0, 1.1, 1.2, 1.4 (because I can't count) and 1.5mm in width. The goal is to find a sweet spot I can push a 1mm pin through - when you 3D print a circle, it's not exactly the width of the geometry; it'll shrink a little bit, so a 1.0mm hole won't actually admit a 1.0mm pin through it.

It looks like I nearly under-estimated it - 1.5mm seems like the goldilocks zone, anything lower would require significant force and it just needs to sit/hold.

#3DPrinting

Okay, I think that's it for now.

The next major step is to validate the PCB I designed with the sockets from AliExpress, and use that to make sure I can actually make a working NES adapter (and breakout board) of any kind - that board is a couple of weeks away.

I've also ordered some 1mm PCB pins that should be the right size for my 3D printed sockets - with those I can design my own custom NES socket breakout and everything.

Time to box this project up for another couple of weeks. 🌛

Here's a thought - once I'm up to the point of plugging a NES controller into an logic analyser and an Arduino to take a look at its communication and programming something to read it, would anyone be interested in watching a livestream of that happening (or even the recording after the fact)?

Would a video of the process of reading basic stuff from an analyser and using that to write a program to talk to a thing be of interest to folks here?

Pleased to announce I am apparently competent at operating calipers and Fritzing. These aftermarket NES sockets from AliExpress appear to fit perfectly with my boards, and I should now be able to start talking to NES controllers.

Don't ask why there's no D1 or D2 pin - the pinout on nesdev.org shows D0, D3 and D4 for this connector: https://www.nesdev.org/wiki/Controller_port_pinout

There are days I look at the crap spread over my desk and think, man, I really have no idea what I'm doing in this hobby.

Then there are days I look at the tiny spiky hovercraft sculpture I've just willed and soldered into being, and think, man, I really have no idea what I'm doing, but this looks kinda pretty.

Lessons learned so far: The extra "hackable" pins need to be slightly further away from the Pro Micro footprint so they're easy to plug in to, and I need to put pin labels outboard as well.

What's going on here is pins 5, 6 and 7 on the Arduino, which are clock, latch and data for the NES socket, are also connected to channels 0, 2 and 4 on my logic analyser. Channel 6 (pin 10 on the Arduino) is just an extra line I can take high to trigger captures in PulseView.

Is this #NES controller busted or am I just doing something fabulously wrong? The data line just echoes whatever the latch line does, maybe suggesting the two are bridged somehow, but is this something a shift register might do in some circumstances?

Data line should only go high if I'm holding a button at an appropriate time in the clock line's cycles, I'm not holding anything in this capture but even if I do there's no change.

Data is just high the whole time without the pad plugged in.

The $10 pad arrived, and is pretty terrible: https://digipres.club/@timixretroplays/114296167646130444

It does work, though - here's my prototype program's output while I'm pressing A, Start and right on the D-pad.

I'm feeling confident enough about this project now to try ordering PCBs to match my 3D printed NES controller sockets.

I found a plugin for Rhino 3D that lets me export geometry to SVG, so I can print the exact outline of my 3D parts on the PCB very easily - how cool does this look!?

My NES breakout boards arrived - I've soldered one up with my 3D printed socket and I'm about to give it a go. Even if this doesn't work at all, it's still a good run of the process and I'm very happy with how it's gone and what I've learned.

The extra big hole in the corner is for an M3 screw to hold the 3D printed socket to the PCB, so yanking the controller's cord doesn't cause the socket itself to slip over and off the pins.

Um, okay - it works perfectly! This is a 3D printed socket I modeled in negative from the plug of a NES MAX controller, with 1.0mm PCB pins soldered to a breakout board of my own design.

It was a bit of a struggle to plug in this $10 repro controller - it was clearly designed for the tolerances of the original console's socket, which my breakout here does not at all have - but the dead MAX's plug slides on flawlessly.

Time to collect a *working* authentic NES controller and validate with that!

I ended up collecting a used NES-039, the new-style or dogbone controller, and that worked perfectly. I've since collected a Four Score as well, here's a thread on that: https://digipres.club/@timixretroplays/114494458860844483

It's now time to design and make a dual NES socket with matching breakout board to match this bad boy.

Unexpectedly, the socket pitch on a NES seems to be 19.5mm - I had fully expected it to be 20, since I've seen a lot of very neat metric measurements in these plugs and sockets already.

I know the spacing here will match the spacing on an original NES console because the Four Score can physically plug into itself - that wasn't just a silly thing to do for a funny photo.

Well, this is the first pass to replicate that geometry, anyway. I don't have time to 3D print this tonight, but that's the next step.

The two screw holes will be used to firmly mount this socket to the PCB.

The Four Score's double plug perfectly fits my 3D printed double socket. Next up is a circuit board to match.

The two plugs on that cable actually wiggle around slightly - it's clearly the same single-plug part in a different housing. So while I've measured the Four Score's sockets at 19.5mm apart, this plug would also certainly work on 20mm pitch sockets.

All of which makes me very keen to see what the NES Satellite's receiver plugs looks like.

And the PCB for this I actually designed last night, on the assumption my socket would fit. I'm choosing not-the-cheapest postage option this time because I'm sick of waiting weeks for projects to advance in between steps.

I've broken out the power, latch and clock signals in pairs so I can experiment with bridging them together - I'm fairly sure the original NES hardware had them all bridged, but maybe I'll discover a reason why it might be useful to page controllers separately at some point.

Five boards ordered on Tuesday, arrived on Monday - not bad for AU$20-ish. Would probably have been here last week if I hadn't opted for black PCBs out of vanity - I might just leave prototyping stuff to the default green in future, which apparently is quicker to turn around.

Anyway. My dual NES socket breakouts have arrived - they'll be a little work to fully assemble and solder up, but they look glorious so far!

First time trying this out. I originally thought I'd be putting the pins into the back of the 3D printed socket and slotting that assembly onto the circuit board, but the fit between the pins and those holes is so precise I had to carefully line them up and pop them into the PCB one by one. I'll be printing a little tool to make doing this by hand easier in future.

The socket screws to the PCB in two places for maximum stability and to stop NES pads from yanking it off the board if they stick.

I have had to partially break it back down again to make it work on my little board soldering attachment. The exact order of operations for assembly is a work in progress.

Again, this is just my little remix of @rasterweb's little soldering board: https://www.printables.com/model/598207-prodoehls-solder-board-v2

Looks like I'll need to make a bigger one to do stuff like this in one go!

And finally, the whole shebang - an #Arduino Pro Micro clone, my own custom dual #NES controller breakout with a #3DPrinting socket, and the #nanoDLA logic analyser ready to help me learn how to talk to a NES Four Score - and later, to help document how to do the same with a NES Satellite!

This is the confluence of a decade plus of hobby learning and making.

A note mainly for myself: CLK and LAT are pins 5 and 6, and channels 0 and 1; P1D0 is pin 7 and channel 2, P2D0 is pin 8 and channel 3.

The straight-through NES sockets have arrived from AliExpress. They are very clearly using the exact same shell as the 90-degree ones, just with straight pins instead of bent ones.

Unfortunately, while the 1mm pins in these connectors would individually fit the 1.1mm through-holes in my breakout board, they won't do so all together - so I'll need to order a separate version of this breakout board to test off-the-shelf sockets like this. That might work better for my 3D printed sockets, too.

With 1.2mm holes, and the extra pins clipped off, the AliExpress NES sockets sit comfortably and snugly in my prototype breakout, with the correct spacing for a Four Score's double plug. This project is now waiting on the arrival of my NES Satellite to validate that plug fitting as well (I think it's more rigid than the FS's so less room for error).

This might be the end of the road for my 3D printed socket, just for now - I'll focus on the better quality outcome for the V1.0 #NES breakout.