This thing is unbelievably low quality. Mine had the arms seized up so I couldn't open it, and in the process of prying it open it snapped, then when i took it apart it snapped again. And again.
I tried to glue it in but then the stupid 'thinkchip' port on the bottom spat tiny metal springs and pins everywhere that i would never be able to replace. This thing is absolute garbage, and I wanted to try to make it into something else so it wouldn't be a complete waste. I had a lamp / clock thing that I wasn't really using so I thought that I could slap it into there and have a little fiddle thing on my desk that was also kinda cool.
Doing a bit of research, this thing is called a 'Pokemon Battle trainer', made by Hasbro in the 2000s. The weird circle bit is a port where you insert a proto-amiibo with 6 pins and it stores data to that. Kinda cool in theory, just one problem.
THEY SOLD THEM WITHOUT THE FIGURES!!!
This happened to me, and while I thought it would be a cool little toy with some features I couldn't use it at all. It's worse than that, the game actually lets attacking pokemon kick your ass without any way to defend yourself. I never found the figure and it went onto a shelf. This was actually a shame because the game has pretty cool graphics and a proper opening cinematic, it's way higher effort than I was expecting.
This is where I reached a separate problem. 7yo me was not missing something, there really is no way to play this without the figurine I don't have. This sorta reinvigorated my childhood rage, and I had to know if this thing was any good or not. I hated it and yet I wanted to play it.
And this is where we hit a wall. There was no way i was going to pay upwards of 20 quid for a crappy figure i'd have to gut and I couldn't find any way of cracking the thinkchip. The only reference I had is someone who opened the earlier version with 2 pins and found an EEPROM, but I have no idea if they changed it for the later one. I also didn't know how the data worked.
I decided to look up a video of the game and luckily someone did provide some video; it's actually pretty alright. You basically just do turn-based battles forever, either against wild pokemon, trainers or team magma. There's some cool visual effects, you level up your pokemon and heal it, so on so forth. Honestly the presentation is pretty fun for how basic it is. I concluded after a while that even if i could spend hours and hours on it, it probably wouldn't be worth it just for the basic game. I was mildly interested in getting a figure but they're rare and expensive, and my unit is still broken.
So I decided to say screw it, and decided to make it a whole lot better while spending less money. I had a Pi Pico laying around, and I thought I could just get a display and then make it play just about any game off the Pico. I couldn't really emulate stuff but I could program some basic games like Space Invaders, Pong, etc.
Displays made specifically for PIs / Arduino are weirdly expensive. Cheapest I could find is pushing 30 which is way more than I wanted to spend for this project. But, you know what's even better than upmarket crap marketed to hobbyists? Pure chinesium crap! I decided to get this monitor, they're apparently made for reversing cameras in cars but crucially they're small, they take composite video in, and they cost only £10 which is insane!
This display actually has 2 composite inputs, meaning that I can use 1 for the Pico, and have another one spare for whatever else. I often test consoles that output composite so having something on my desk I can use to check without getting my AV2HDMI thingy out would also be quite handy. I also got some IC sockets so I could pop my Pico out if I ever needed to, and I have some breadboard to make the composite out / controls.
Luckily someone already did the composite out for me which is handy. It uses a couple of the Pico's pins, and a whole bunch of resistors to make an NTSC signal. It's a lower resolution and only in Black and White but it'll do for my needs. I didn't want anything super distracting on my desk anyway, and alot of arcade machines were in B/W anyway. That leaves a couple GPIO pins for controls, LEDs, clock, a buzzer for audio, etc.