Both Kosmic, Darbian, and myself have input displays. I use a program called NintendoSpy, however, it’s not just a matter of downloading a program. I soldered cables to a NES controller extension cable to split the signal to go to my NES and an Arduino Uno. It’s complicated and I’m not sure is anyone sells them.
If you feel comfortable with a soldering iron there's a step by step guide with pictures online... I don't have the link with me, but it exists. I built mine. Using an arduino uno, a nes extension cable, and code using Nintendo spy... You can buy the whole thing (if you do it yourself) for like $35.
I know some people that commissioned it out. If you ask around you can probably find someone that's willing to make them at a profit
At the risk of feeding a troll - I found the link of the article that tells you, step-by-step, with pictures, how to create your own controller display for the NES console. You don't NEED to be able to solder, you can instead just use those plastic twist connectors to splice the cables. I followed this guide exactly, and created a controller display, and didn't spend much money. It's actually pretty easy, even for someone with limited experience in that sort of thing.
https://github.com/jaburns/NintendoSpy/blob/master/docs/guide-evilash25.md
Effective immediately, any submissions using the SNES9x emulator will not be verified. The SMB1 mod team has concerns about its integrity due to its ability to overclock and remove lag frames, which may not be easily detectable. Additionally, we request that all BizHawk submissions avoid using the S
