Worklog N64 Minii

[Bob]

God I hate the name I gave this, but it looks like having two 'i's is a requirement around here.

I've always wanted a mini N64, but it looks like Nintendo isn't going to be doing that any time soon, so I must take matters into my own hands. I've considered making an N64 case for a raspberry pi, or any small PC, but it still looks like emulation on those systems sucks hard. My personal standards for runtime performance are pretty strict, and it looks like N64 emulation on anything small just plain sucks for a large number of games (it's not even that great on a full-blown gaming PC IMO). But, I've always been pleased with the performance and picture quality of the N64 VC console games on the Wii. And when I learned a couple weeks ago that the Wii can be trimmed to the size of a credit card, I knew what I had to do.

• Fit a Wii into a 60% scale model of an N64
  
• Put Game Cube ports on the front
  
• Install every N64 VC release on it (only 21 games, but most of my favs are on there)
• Make some N64 controllers into functioning Game Cube controllers
  
• (alternatively) Make an N64-to-gamecube converter (the opposite of what you can find online)

First the case. I couldn't find any good existing models of the N64 online. I found one RPi case that mostly met my standards, but I didn't want to mess with direct STL editing; I wanted something easy work with in Fusion360. So, I decided I'd make it from scratch. I imported the drawings from Nintendo's original patent application as canvasses in Fusion 360 and learned how to use their sculpting tools (the N64 is pretty curvy, and I couldn't think of any way to use more traditional modelling techniques). I may make a tutorial on this at some point, but I want to wait until after I've competed my case. After WAY too long, I ended up pretty happy with the result.

I've spent the last week working out how to do the power and reset switches in a way that doesn't rely on glue to keep the slider and button attached to the case. After a few different approaches to the power switch, I settled on the following.

The slider body consists of 3 separate pieces glued together. The little locking legs are printed flat on the bed, and glued into slots in the slider. This was for two reasons: I didn't want to use supports to print it, and this makes them less fragile when bending them. The power switch is a cheap little slide switch I bought a 100 pack of on Amazon.

Above are the components before assembly (I printed just a small part of the top of the case to test).

And this is the assembled switch. The PCB is held in with screws, so everything can be easily disassembled. In addition to holding the switch, the PCB prevents the locking tabs from bending in and allowing the slider to pop off.

This is the reset switch. Unfortunately, I had to use a clicky tact switch for this one. Both my switch assemblies need to be super low profile or they will interfere with the controller ports. This is a low profile, two-legged tact switch I had laying around. It works beautifully, but doesn't feel like the real thing . Oh well, I can't spend forever getting a button that nobody uses feel just right.

Next, I'm going to design the cutouts for the control ports, but to test things, I'm going to need some control ports to test fit. So, I'll be shifting over to installing PortablizeMii on the Wii, and then chopping parts out!

 

[Bob]

Portablize Mii installation went smoothly, and the bluetooth module has been relocated. IT WAS TERRIBLE. I thought people were overblowing how tough that was. I went into this so cocky about my SMT soldering skills, but this was a whole new level. I'm shocked I got it without bridging them together or to ground. The wiimote connected right up. The joints stand up well to tugging too.

Next up, U10 relocation, then building custom regs (out of some spare TPS54360 boards I have laying around), and then time to get out the dremel

 

[Wesk]

The model looks great, I'm looking forward to see it fully printed.

 

[Stitches]

Portablize Mii installation went smoothly, and the bluetooth module has been relocated. IT WAS TERRIBLE. I thought people were overblowing how tough that was. I went into this so cocky about my SMT soldering skills, but this was a whole new level. I'm shocked I got it without bridging them together or to ground. The wiimote connected right up. The joints stand up well to tugging too.

Next up, U10 relocation, then building custom regs (out of some spare TPS54360 boards I have laying around), and then time to get out the dremel

For next time you don't have to solder both traces next to each other. You can do one, move half an inch along and do the other for less hassle.

Also I can't see the images you linked, pls use the site uploader or imgur.

 

[Bob]

For next time you don't have to solder both traces next to each other. You can do one, move half an inch along and do the other for less hassle.

Yup, that's what I did. For the first wire, I scraped away too much soldermask, and exposed both traces and the ground planes. I thought there was no way I'd get the wire down without soldering to both traces, but it worked. For the next wire, I was able to just expose the soldermask for the trace I wanted.

Also I can't see the images you linked, pls use the site uploader or imgur.

Oops, I copy/pasted the image, and I figured it uploaded to the site. Turns out Google Photos and the forum are too smart about the copy paste, and the forum turned the image into a direct link, even though I'm sure I copied the image and not the image address. I had to paste into Paint, then copy paste to the forum (I could have saved the image, then "Upload a File", but that felt like too much work). Should be good now.

 

[Stitches]

Yup, that's what I did. For the first wire, I scraped away too much soldermask, and exposed both traces and the ground planes. I thought there was no way I'd get the wire down without soldering to both traces, but it worked. For the next wire, I was able to just expose the soldermask for the trace I wanted.




Oops, I copy/pasted the image, and I figured it uploaded to the site. Turns out Google Photos and the forum are too smart about the copy paste, and the forum turned the image into a direct link, even though I'm sure I copied the image and not the image address. I had to paste into Paint, then copy paste to the forum (I could have saved the image, then "Upload a File", but that felt like too much work). Should be good now.

Yep that worked, I see my advice wasn't needed afterall lel

 

[Bob]

I have my power supply boards built up, and upon doing so, realized they were going to be way to big to fit into my case without trimming them down, which is way more effort than it's worth. But they'll be good enough for testing, and I'll post pictures and talk about this more when I do my actual trim.

Instead of jumping into trimming my board, I got distracted by designing my own power board. I wanted something like the PowerMii Lite, but mistakenly thought it was a discontinued product with closed source (realized later I was wrong on both counts). Oh well; the board I designed has some additional features that suit my project.

Goals for my power supply

1. Be small. Can't really afford much more space than 20mm by 60mm
2. Take 5V 3A for input power (I have a bunch of these laying around)
3. Have an enable pin for turning on and off the power supply. The slide switch I'm using for power is only rated for 200mA.
4. Design the 3.3V, 1.15V, and 1V regulators for 3A output, and 15V input voltage. I'm over-engineering to give myself maximum chance of getting it right on the first try, instead of pushing all my components right to their spec. There could be some reason I this is a bad idea, but I can't think of one.
5. Be easy to hand assemble (using skillet reflow) and rework. Smallest passives are 0603 (1608 metric). I'm probably the only person on this forum interested in a board with this specific feature set, so an automated assembly run is out of the question.

And here's the result. The board measures in at 18mm by 56mm. This is WAY longer than the PowerMii Lite, and it's not even 4 full regulators, since I'm using 5V to power it. The size is largely due to goals #4 and #5. Overall, I'm very happy with how it looks, and there's plenty of room for this in my case.

The regulators are built around the TPS564201, and I spec'd all the components using TI's online WEBENCH tool (cheating, I know). 5V out is controlled by an AP2171 USB switch. The enable pins of all the ICs are pulled down; to turn on the board, it needs to be held at 5V with a slide or toggle switch.

If anyone wants the source and the BOM, I'll gladly share it, but I was planning to wait until I built the thing and confirm it works. This is my first attempt at an SMPS.

Time to stop procrastinating now and actually trim my damn board.

 

[modler2]

Just in case you wern't aware Rahpnet makes a N64 to gamecube controller adapter here: https://www.raphnet-tech.com/products/n64_to_wii_v2/index.php

I'm not sure if it fits your needs but I thought I'd include it just in case! I love the idea btw!

 

[Stitches]

I was about to say something about the efficiency of those regs, but then I remembered you're making a mini. Looks damn good btw, I like the USB C implementation.

 

[havocb]

Awesome! A mini 64 will be my next build for sure depending on how well I do with the Wii

 

[Bob]

Okay, lots of progress to report!

The power boards, which I'm dubbing MiniiPS, came in, and they work (thank you Shank and Jeff for saving me from forgetting the 5.1K pulldowns on the CC lines)! There was an issue with my 5V digital switch, I mixed up the input and output pins on the AP2171 when I made library part in KiCAD. I fixed it with some bodge wiring, but it was real nasty work. I've fixed the issue in the design, so it'll be fine in the files I'm releasing.

Assembly was surprisingly easy, despite the high part density. After stenciling, I put the bare board in the electric skillet that I use for reflow, and tweezered all the components in place.

Then using just a stopwatch and an IR temp gun, I followed the temperature profile in the solder paste datasheet as best I could. I also "stir" occasionally to avoid hotspots. And here's a pic of the final product complete with my bodge wiring. The wires on the bottom right go to the power switch. The enable pad (on the underside of the board) is pulled low by default; when a power switch pulls the pad to 5V, the regs and 5V Out switch turn on.

I also trimmed my board, put the finishing touches on the case design, and printed the bottom half.

Ignore the stock heatsink on there, I'm going with the integrated fan heatsink I've seen a couple places on the forums. I just haven't designed and printed the clamp piece I'm going to use to secure it to the board. I had to relocate my bluetooth a second time because it was going to interfere with that clamp, but ultimately, I like its new location better.

Surprisingly enough, everything is working! I only have composite video hooked up to the AV connector for now, but I plan to wire everything needed to use any Wii connector, including an HDMI dongle. I really hope the latter doesn't rely on 12V, because I won't be able to make that work.

Next I need to relocate my MX chip, print the heatsink clamps, and print the top half of the case.

 

[Bob]

So, I've printed the top half, but things didn't go well, and I'll be redoing it, but it's cool to have it in my hands at long last.

Without thinking, I did 20% infill, 3 solid top/bottom layers, and 0.1mm layer height. This caused bubbles in the top fill. I will be going with 100% fill for my next attempt. Also, I'm going to increase the layer height to 0.2-0.3 on the bottom part to improve overhang performance for the control ports (thanks Aurelio). Depending on how it looks after that, I may try my hand at wetsanding, but I'll need to look further into that. I've only seen people doing that when painting their prints, and I'm not planning to paint. I'm going to paint the control port faces (though, the black is kinda growing on me), but I don't want to paint the whole case.

I've also settled on my cooling method. I'm just going to use a single 40mm fan/heatsink placed right on the GPU and CPU together, like the Wii Nano.

Now gonna wire up the GC ports and reprint my top.

 

[Gman]

Very nice so far.

Is that plastic piece for holding the heatsink on the wii? I would recommend printing it in PET unless the cooling setup is perfectly cool. Otherwise it will get a little bendy and could eventually warp off.

 

[Bob]

Yeah, it holds down the heatsink. It's currently PLA, but it will be PETG; this was a quick test fit.