Is it possible to have a 3DS unlock your doors?

[Siletrea]

Hi, so I had a really interesting thought the other day while over at my buddies house because he and I both carry a 3DS with us wherever we go! (Streetpass 2025!)
his apartment uses one of those tiny key-chain scanners (NFC tech) and since some 3DS models like the 2DSXL has the NFC readers built into them by default? I was wondering if there's a way to load your scannable keytags into a 3DS/2DS and use it as your keyfob rather then risk damaging your ignition from the extra weight on the keychain (this does actually happen!)

this also means that one could potentially load in their amiibo figure data as well into the 3DS/2DS and use that data instead of the figurine when traveling/gaming! (I certainly bring both my 2DSXL and Switch when traveling)

what do you guys think??

 

[Thardus]

Ha, that's cool: you guys carrying them around. great system.

His apartment is probably 125kHz RFID and not NFC so no, I highly doubt you can get that to work.

Post automatically merged: Jul 21, 2025

Also, I'd rather not risk damaging my 3DS over some plastic transfer from the RFID keyfob on the ignition. but that's just me.

You could carry around another gadget: a Flipper Zero. you can read/save RFID keys, and you can write them to your own writable key fobs if you want. you can also emulate amiibo.

Flipper Zero can also play games like Snake, haha

 

[Siletrea]

Ha, that's cool: you guys carrying them around. great system.

His apartment is probably 125kHz RFID and not NFC so no, I highly doubt you can get that to work.

Post automatically merged: Jul 21, 2025

Also, I'd rather not risk damaging my 3DS over some plastic transfer from the RFID keyfob on the ignition. but that's just me.

You could carry around another gadget: a Flipper Zero. you can read/save RFID keys, and you can write them to your own writable key fobs if you want. you can also emulate amiibo.

Flipper Zero can also play games like Snake, haha

oooh I had no idea that it could be a different technology in it! are you able to explain the differences? I'm really curious!

also I've been looking at flippers and they're super neat! but I also know the modding community around here is wicked smart/competent so I figured that instead of buying a new device only to find that the 2DS could do it anyway? I'd ask here first and find out directly from the actual coders whats possible and whats not!
I really appreciate this answer!

this will probably nerf my other idea as well but I figure I should ask, is there a way of making a offline barcode for scanning from a system that does barcode refreshers every 10 minutes? (I use Mcdonald Kiosks and have been trying to get a physical card and move away from the app since its conception,but every-time I try to ask support about it? its all AI now and I can't talk to a real person)

 

[Thardus]

I guess technically NFC is a subset of RFID but anyway, yeah, most key fob/card entry systems are low-frequency RFID 125kHz whereas NFC is a different (higher) frequency altogether: 13.56 MHz. The hardware/radios in the 3DS cannot communicate on 125kHz. The 3DS has NFC and wi-fi (2.4GHz) capabilities only and doesn't operate at the lower frequencies: so, a hardware limitation

barcode refreshers, hmm, that sounds like a derivative of TOTP (time-based one time passwords). usually these are in the form of 6-digit multi-factor auth or something; sounds like that's converted into a barcode to make it easier/contactless. I think it's technically possible but probably not in this scenario with McDonalds. probably easier and better for you to ditch McDonalds and fast-food altogether.

 

[Siletrea]

I guess technically NFC is a subset of RFID but anyway, yeah, most key fob/card entry systems are low-frequency RFID 125kHz whereas NFC is a different (higher) frequency altogether: 13.56 MHz. The hardware/radios in the 3DS cannot communicate on 125kHz. The 3DS has NFC and wi-fi (2.4GHz) capabilities only and doesn't operate at the lower frequencies: so, a hardware limitation

barcode refreshers, hmm, that sounds like a derivative of TOTP (time-based one time passwords). usually these are in the form of 6-digit multi-factor auth or something; sounds like that's converted into a barcode to make it easier/contactless. I think it's technically possible but probably not in this scenario with McDonalds. probably easier and better for you to ditch McDonalds and fast-food altogether.

thank you so much for the explanation! this is super interesting stuff! I've been fascinated with these types of frequencies for awhile (due to me having a older cellphone that's a CDMA and my curiosity of what it would take to get it running in modern times again) but I get treated horribly when I ask, so I really appreciate you explaining it so nicely!

and yes I'm moving away from the fast food! the fries are just a good treat sometimes haha

 

[Thardus]

thank you so much for the explanation! this is super interesting stuff! I've been fascinated with these types of frequencies for awhile (due to me having a older cellphone that's a CDMA and my curiosity of what it would take to get it running in modern times again) but I get treated horribly when I ask, so I really appreciate you explaining it so nicely!

and yes I'm moving away from the fast food! the fries are just a good treat sometimes haha

no worries! I love getting old technology to work in the modern age. I still have a Windows 98 machine (with CRT monitor) that can connect to Unreal Tournament servers and play on the internet. I hate that not-very-old smart phones are obsoleted so quickly when the hardware is still functional.

PS. Tallow-fried potatoes/fries are the best . When I was a kid McDonalds used only tallow but now they use mainly seed oils (PUFAs).

Good luck!

 

[Siletrea]

no worries! I love getting old technology to work in the modern age. I still have a Windows 98 machine (with CRT monitor) that can connect to Unreal Tournament servers and play on the internet. I hate that not-very-old smart phones are obsoleted so quickly when the hardware is still functional.

PS. Tallow-fried potatoes/fries are the best . When I was a kid McDonalds used only tallow but now they use mainly seed oils (PUFAs).

Good luck!

if you don't mind me asking? do you know anything about cellphones and their networks? my old CDMA non-smartphone is a "LG Keybo ENV2" and I'd LOVE to find a way to safely get it working on newer networks again so I can enjoy the QWERTY keyboard and great battery life!

also I'm so jelly of your setup! my folks threw out my CRT and I'm still mad about it

 

[TheStonedModder]

The best way to handle this imo and it’s still going to be a lot of work

Is to make a 3ds homebrew app that talks to home assistant (which links to Google home Alexa and Siri)

Which can then talk to your smart locks

 

[Siletrea]

The best way to handle this imo and it’s still going to be a lot of work

Is to make a 3ds homebrew app that talks to home assistant (which links to Google home Alexa and Siri)

Which can then talk to your smart locks

neither my bestie or I use smart systems, but this is a REALLY cool idea!

 

[TheStonedModder]

neither my bestie or I use smart systems, but this is a REALLY cool idea!

They are super cheap to get into.

A Google nest/home mini is $20 new even cheaper used

And there’s hundreds of cheap smart light bulbs and other IOT devices. That being said you do get what you pay for. When I was buying those cheap bulbs they’d die like every 2 months

Then home assistant can be ran on pretty much anything

 

[Thardus]

They are super cheap to get into.

A Google nest/home mini is $20 new even cheaper used

And there’s hundreds of cheap smart light bulbs and other IOT devices. That being said you do get what you pay for. When I was buying those cheap bulbs they’d die like every 2 months

Then home assistant can be ran on pretty much anything

+1 for HomeAssistant though I run as much stuff "offline" (not cloud-based) as possible

 

[N7Kopper]

no worries! I love getting old technology to work in the modern age. I still have a Windows 98 machine (with CRT monitor) that can connect to Unreal Tournament servers and play on the internet. I hate that not-very-old smart phones are obsoleted so quickly when the hardware is still functional.

Planned obsolescence is part of the assault on capitalism, I'm afraid. Why would fascists (original definition) want to compete with themselves? Why make something better if you can stop people from using your old stuff? If people can use their old stuff, they might discover for themselves that ideas you've made politically incorrect aren't so wicked after all.

But as it is, getting your 3DS to open your door would be easiest done if you have a non-proprietary "smart home" (and you shouldn't be using a proprietary one! There's no reason for you to put your home's server base behind a black box in someone else's computer) and can connect the 3DS to the same LAN as the server box that controls your door.

 

[XFoxPrower]

I've all but given up McDonalds. I get thirsty and all they want to do is charge for refills. Some are happy to if you ask, but still a hassle. And still trying to get Win98 to not bsod on Vita. So New 3DS / 2DS NFC readers can broadcast too?

 

[Justaduckwhogivesnofucks]

Hypothetically yes, because the 3DS has an NFC scanner you could wire up a NFC tag of some sorts and connect it to an Arduino with a battery with some custom code you can make it so when the NFC tag is scanned it opens up the door by sending data to a web server when it gets scanned

 

[The Real Jdbye]

Hi, so I had a really interesting thought the other day while over at my buddies house because he and I both carry a 3DS with us wherever we go! (Streetpass 2025!)
his apartment uses one of those tiny key-chain scanners (NFC tech) and since some 3DS models like the 2DSXL has the NFC readers built into them by default? I was wondering if there's a way to load your scannable keytags into a 3DS/2DS and use it as your keyfob rather then risk damaging your ignition from the extra weight on the keychain (this does actually happen!)

this also means that one could potentially load in their amiibo figure data as well into the 3DS/2DS and use that data instead of the figurine when traveling/gaming! (I certainly bring both my 2DSXL and Switch when traveling)

what do you guys think??

Emulating a NFC or RFID tag is a whole different beast than simply reading (or writing) them, even on Android phones there isn't a consistent way to emulate a NFC tag. There have been methods throughout the times to supposedly capture and replay NFC tags but I could never get any of them to work and I think they're limited to working on certain custom ROMs like LineageOS on specific hardware. The NFC functionality on the 3DS is highly abstracted and there isn't direct hardware access AFAIK so slim chance anything like this would be possible.

 

[Sono]

I don't think that the NFC in the 3DS (either the external one, or the internal one) can act as a tag, only act as a "master", so definitely not working that way.

Perhaps over IR, but we still have very limited research (as far as I know) about bitbanging the IR LED with correct timing.

WiFi only works if you have an internet connection, a conntest relay, or patched ac sysmodule.

Edit: I got 'd, lol

 

[Justaduckwhogivesnofucks]

I don't think that the NFC in the 3DS (either the external one, or the internal one) can act as a tag, only act as a "master", so definitely not working that way.

Perhaps over IR, but we still have very limited research (as far as I know) about bitbanging the IR LED with correct timing.

WiFi only works if you have an internet connection, a conntest relay, or patched ac sysmodule.

Edit: I got 'd, lol

Bluetooth is an option however if your looking for security for the love of aphrodite please do not do this anyone with a flipper zero can just go *beep* and then its knock knock I broke into your house with my 3ds and I have a glock

 

[TheStonedModder]

Bluetooth is an option however if your looking for security for the love of aphrodite please do not do this anyone with a flipper zero can just go *beep* and then its knock knock I broke into your house with my 3ds and I have a glock

Ain’t no one going from house to house with a flipper zero yall are paranoid

Especially if they have a gun. They aren’t going to resort to coming in all nicely and by luck

 

[Justaduckwhogivesnofucks]

Ain’t no one going from house to house with a flipper zero yall are paranoid

Especially if they have a gun. They aren’t going to resort to coming in all nicely and by luck

unrelated but what in the actual avocado fuck is that profile picture

 

[Sono]

Bluetooth is an option however if your looking for security for the love of aphrodite please do not do this anyone with a flipper zero can just go *beep* and then its knock knock I broke into your house with my 3ds and I have a glock

Where is Bluetooth in the 3DS though?

I mean, there *is* a Bluetooth coprocessor, but we haven't yet found a way to unlock it, let alone use it.