Handheld famicom

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LasseLömsk
Posts: 15
Joined: Mon Oct 28, 2019 7:46 am

Handheld famicom

Post by LasseLömsk » Fri Nov 15, 2019 9:44 am

So. I've started doing some soldering, mods, gameboyzero and other stuff which I noticed that i really enjoy. Last thing I did was a AV mod for the famicom I bought.
What I noticed when I was opening it up is that the pcb was really small compared to the NES Frontloader I did the RGB mod on. And that got me thinking. Maybe it would be an interesting project next to do a handheld famicom. So I ordered an old famicom dirt cheap (might be something broken) and its on its way. Biggest reason why I am doing this is because I wanted to learn how to design and make PCBs. The Famicom seems to be a very well documented system with schematics on the web, which will in my head hold my hand as I don't need to invent the wheel, so to speak. In the design I am also going to use this alternative "Power schematic" adn try to implement it https://www.youtube.com/watch?v=6UGa3aDpMOE. A Headphone jack and volume control need to be added and maybe speakers. As a screen I will use one of those Carparking monitors as they are often a good size and they do take in composite video. There are also alot of documented modding on how to make them go of 5v. the case will use Cartridges of course and will have a 3D printed case. The Idea is to have just the player one controller as the built in controller but I'm goin to try and implement the microphone from the player 2 controller so you can scream at the console and kill stuff in Zelda.

Image

I have two main reasons for starting this thread:
First is to share my success and failures and hopefully many laughs throught the project.
Secondly is to give people the oppurtunity to look stuff over and shout at me if I am doing something totally wrong. I am stilla novice at this stuff and don't want to blow stuff upp ;)

Best regards Lasse!

lidnariq
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Location: Seattle

Re: Handheld famicom

Post by lidnariq » Fri Nov 15, 2019 11:20 am

Here's some previous implementations for inspiration:
GameAxe
someone's 3d printed thing

Obviously if you don't want your ideas tainted by previous implementations, don't look :)

LasseLömsk
Posts: 15
Joined: Mon Oct 28, 2019 7:46 am

Re: Handheld famicom

Post by LasseLömsk » Fri Nov 15, 2019 12:47 pm

lidnariq wrote:Here's some previous implementations for inspiration:
GameAxe
someone's 3d printed thing

Obviously if you don't want your ideas tainted by previous implementations, don't look :)
Thanks! The GameAxe is kind of what I am going for!

jmr
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Location: Ontario, Canada
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Re: Handheld famicom

Post by jmr » Fri Nov 15, 2019 3:01 pm

A handheld, portable NES that's NOT based on a famiclone / NOAC is something I've been hoping someone would make for YEARS. I use a NES as a part of a live band and I've been hoping to find ways of miniaturizing and making my setup more portable.

If you ever make this into a product, even a short run of hand made systems, I want to be first in line to buy one.

LasseLömsk
Posts: 15
Joined: Mon Oct 28, 2019 7:46 am

Re: Handheld famicom

Post by LasseLömsk » Mon Nov 18, 2019 5:13 pm

jmr wrote:A handheld, portable NES that's NOT based on a famiclone / NOAC is something I've been hoping someone would make for YEARS. I use a NES as a part of a live band and I've been hoping to find ways of miniaturizing and making my setup more portable.

If you ever make this into a product, even a short run of hand made systems, I want to be first in line to buy one.
Thats Awesome. So from your perspective what do you need? Output and stuff. More how do you use the NES/famicom. I am doing this with the famicom in mind but i might find solutions for the Nes aswell, if it is not that complex. And the thought of this project is to be open source later on and right now I dont have any plans of making money out of this.

Best regards Lasse

pakosup
Posts: 34
Joined: Mon Apr 24, 2017 10:23 pm

Re: Handheld famicom

Post by pakosup » Mon Nov 18, 2019 10:42 pm

Yet another "Coolbaby X7"?
the problem with this build a power efficiency and size.
Chinese devices looks better but quality is below the average
https://ru.aliexpress.com/item/32993717175.html
https://ru.aliexpress.com/item/32998676502.html

lidnariq
Posts: 9301
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: Handheld famicom

Post by lidnariq » Mon Nov 18, 2019 11:12 pm

Rhubarb card slot
I don't know why it was translated that way, but the ensuing mental images really amuse me.

jmr
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Location: Ontario, Canada
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Re: Handheld famicom

Post by jmr » Tue Nov 19, 2019 9:04 am

LasseLömsk wrote:
jmr wrote:A handheld, portable NES that's NOT based on a famiclone / NOAC is something I've been hoping someone would make for YEARS. I use a NES as a part of a live band and I've been hoping to find ways of miniaturizing and making my setup more portable.

If you ever make this into a product, even a short run of hand made systems, I want to be first in line to buy one.
Thats Awesome. So from your perspective what do you need? Output and stuff. More how do you use the NES/famicom. I am doing this with the famicom in mind but i might find solutions for the Nes aswell, if it is not that complex. And the thought of this project is to be open source later on and right now I dont have any plans of making money out of this.

Best regards Lasse
The consoles I use have been modified to have 1/4" or RCA outs connected to the pins of the 2A03 directly (w/ a 1uf 50V cap). I also run a third connector out from the powerpak pin for using it's expansion audio (side note: I've thought about adding a output to the powerpak cart itself, just so if I need to swap to a replacement NES in a pinch I can get workable audio without needing a modded console, but there's not much space for that).
My current setup is a toploader NES with a backup camera LCD screen bolted to the top of the console. I've removed the 7805 regulator and replaced it with a switching regulator, and i'm using 12V supply to power both the screen and the NES, with the console power switch controlling both.

+1 to open source!

LasseLömsk
Posts: 15
Joined: Mon Oct 28, 2019 7:46 am

Re: Handheld famicom

Post by LasseLömsk » Sun May 17, 2020 7:36 am

okay... So it has been a while... Having a kid takes up some of your time which you usually had for other things. But I do believe it also was better for the project aswell. I've recently noticed something that makes me rethink everything I actually have planned for this. And this is something quite obvious. I know I said before that I wanted to learn how to make PCB and other stuff but I bit off more than I could chew as a starting project. And secondly, the famicom PCB is already small... Really small. I bet some good makers could make it even smaller and more optimal but I don't think I can. But look at this: the PCB is as lagre as a gameboy :)
Image

The shielded area is actually a seperate PCB with RF, change channel and also where the power comes in at around 9v. But the board itself seems to need only 5 volt, as you can se by the voltage regulator and also in this hack video: https://www.youtube.com/watch?v=6UGa3aDpMOE.
So the plan is to solder that away. I also goint to solder way the exitport and put it somewhere else in the final build and just run wires to it. This is because i want to put the PCB sideways to make a wide handheld where the screen is in the middle. And i dont want to have an exit port underneath my hand.

I find all of these steps quite easy to do and it will save me alot of time to keep the board and also it will not really destroy any part of it. But I am also planning of desolder the whole pinconnector. I dont want to endup with a handheld that just have a cart sticking out in a weird angle on the back. I want most normal sized Famicom cartridges to be flush against the handheld, almost like a gameboy. So I intend to mount it on a saperate PCB (Just of intergeral porpouses to make it more stable), and run wires from the board to that. This in inteded to be mounted on the back piece of the handheld with stable fixed points. This seems harder, and right now I am looking for some good cables and connections wich can be easy disconnected when I want to take the handheld apart. 60 cables are quite alot. XD

Finally I am also thinking about to make it extra old fashion and make it run of AA batteries in the back. :)
Got the inspiration of video: https://www.youtube.com/watch?v=zTqcb8h ... vA&index=2
Instead of always seeing the colour go away and also the dithering, is there a electronic device that cuts the current if it drops below a certain voltage?

Im going to try to make most of the handheld out of wood aswell to make it look extra special :D

To do list:
desolder power/RF pcb
make a new "power PCB" for screen and board with a V5 regulator
Desolder the pinconnector
design an make a new pinconnector PCB for mounting
Find and solder cables from the main PCB to the Connector PCB
design and make the case out of wood
most likley modify the car monitor ro run off 5 volts
add a speaker with volume control al la gameboy
add batterycompartment
assemble

lidnariq
Posts: 9301
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Location: Seattle

Re: Handheld famicom

Post by lidnariq » Sun May 17, 2020 11:56 am

LasseLömsk wrote:
Sun May 17, 2020 7:36 am
Finally I am also thinking about to make it extra old fashion and make it run of AA batteries in the back. :)
AAs don't have that much battery life; maybe 2 amp*hours. You'd be lucky to get even Game Gear levels of battery life.
Instead of always seeing the colour go away and also the dithering, is there a electronic device that cuts the current if it drops below a certain voltage?
Yes, but why bother? You'll want an indicator for low battery anyway.
make a new "power PCB" for screen and board with a V5 regulator
You'll get drastically more battery life if you switch to some kind of switching regulator, like a SEPIC or a boost-buck. Standard 7805s are inefficient at the best of times. If you buy a module, buy a quality one - I remember someone mentioning their NES was killed by a cheap one.


I know you said that you didn't want to redesign the PCB, but you could make it substantially smaller (and possibly lower power) if you replace the RAMs and other small parts with modern replacements. The CPU and PPU unfortunately have to remain as-is.

LasseLömsk
Posts: 15
Joined: Mon Oct 28, 2019 7:46 am

Re: Handheld famicom

Post by LasseLömsk » Mon May 18, 2020 1:24 am

Thank you for the reply!
Yes it looks like I have to abandoned the idea of as batteries for that and also size reasons. Too sad but yes, totally unpractical.

And yes thank you for the heads up about the voltage regulator . I really don't need inefficiency from that and I will look in to the boosts.

Changing out the ram and other stuff I am quite reluctant to. Mostly cause I want as much as "original" as possible (just who I am). But I might later reconsider and do as you say. How much will it save, energy wise do you think?

Thanks again?

lidnariq
Posts: 9301
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: Handheld famicom

Post by lidnariq » Mon May 18, 2020 11:01 am

LasseLömsk wrote:
Mon May 18, 2020 1:24 am
How much will it save, energy wise do you think?
Maybe 5-10%? My NES consumes 350mA without a cart.

I can't find the datasheet for the XRM6216 in your Famicom, but my NES has a LH5116, which says that it consumes 25mA typical while enabled (assume it's enabled half the time, so ~12mA typical per RAM in the NES), and the modern IS62C256AL (yes, it's 16 times as much RAM) consumes half that. Replacing the 74LS373 and 74LS139 with HCT, ACT, or ALS will shave off another 5mA or so.

Most of the power consumption will still be the CPU and PPU. You could undervolt them by 10%, which will also reduce current consumption, so that's the easiest way to increase battery life. (However, colors will get dark. You'd have to revise the video output stage to compensate)

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