add gameboy blog post

input/blog/2025/2025_03_16_gameboy.md

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+title: Blog
+post: Game Boy Color modding and experiments
+description: Adding an OLED display and building a Game Boy Printer emulator for the Game Boy Camera
+date: 2025-03-16
+comments: true
+---
+
+I recently pulled out my old childhood Game Boy Color from a drawer to play around with it.
+The idea is to use [LSDJ](https://www.littlesounddj.com/) to accompany [LARS](lars_v2.html).
+Unfortunately I kinda forgot _how bad_ the GBC screen is, without any backlight.
+
+So I looked around AliExpress a bit and found the [store](https://www.aliexpress.com/store/1102204288) of [HISPEEDIDO](https://hispeedido.com/home).
+They offer many nice modding kits for old consoles, so I got the [OLED screen and USB-C battery replacements](https://www.aliexpress.com/item/1005007009553275.html).
+
+<!--%
+lightgallery([
+    [ "img/gb_mod_9.jpg", "Front of modded GBC" ],
+    [ "img/gb_mod_8.jpg", "Back of modded GBC with USB-C charging" ],
+])
+%-->
+
+The installation is very easy, you just need to solder a single wire according to their manual and it all worked out fine.
+
+I also found my old Game Boy printer, a small thermal printer that can be used with some games and, most importantly, the Game Boy camera.
+
+<!--%
+lightgallery([
+    [ "img/gb_mod_10.jpg", "My old GB Printer" ],
+])
+%-->
+
+I didn't have my old Game Boy camera, as I took it apart and used the sensor many years ago for my [robot](xyrobot.html).
+So I got a used one on eBay.
+
+<!--%
+lightgallery([
+    [ "img/gb_cam_1.png", "Cat pic of Ares (1)" ],
+    [ "img/gb_cam_2.png", "Cat pic of Ares (2)" ],
+    [ "img/gb_cam_6.png", "Cat pic of Ares (3)" ],
+])
+%-->
+
+Here are some photos I took for testing.
+
+<!--%
+lightgallery([
+    [ "img/gb_cam_7.png", "Cat pic of Ares (4)" ],
+    [ "img/gb_cam_3.png", "Ares and Aphrodite together" ],
+    [ "img/gb_cam_12.png", "GTA:SA screenshot" ],
+])
+%-->
+
+As you can tell, Ares has better contrast compared to Aphrodite 😄
+
+<!--%
+lightgallery([
+    [ "img/gb_cam_4.png", "Cat pic of Aphrodite (1)" ],
+    [ "img/gb_cam_5.png", "Cat pic of Aphrodite (2)" ],
+    [ "img/gb_cam_8.png", "Cat pic of Aphrodite (3)" ],
+])
+%-->
+
+And you really need to take the lighting situation into consideration.
+
+<!--%
+lightgallery([
+    [ "img/gb_cam_9.png", "Cat pic of Aphrodite (4)" ],
+    [ "img/gb_cam_10.png", "Cat pic of Aphrodite (5)" ],
+    [ "img/gb_cam_11.png", "Cat pic of Aphrodite (6)" ],
+])
+%-->
+
+To get the pictures off the cartridge I built an ESP8266-based WiFi printer emulator.
+I ordered these [PCBs](https://github.com/cristofercruz/gbp-esp-shield-pcb) and soldered them to a [LILYGO TTGO D1 mini](https://www.aliexpress.com/item/4000429611680.html) as mentioned in the README of the PCB repo.
+The OLED screen was still left over from my [E-Cig repair](2024_09_16_istick_pico_oled.html).
+The software running on there is the [wifi-gbp-emulator](https://github.com/HerrZatacke/wifi-gbp-emulator).
+
+<!--%
+lightgallery([
+    [ "img/gb_mod_1.jpg", "Using the WiFi GB Printer emulator" ],
+    [ "img/gb_mod_7.jpg", "Front of WiFi GB Printer emulator" ],
+    [ "img/gb_mod_6.jpg", "Back of WiFi GB Printer emulator" ],
+])
+%-->
+
+To get back to the original topic of creating sounds though, there are multiple options.
+The most popular one, as mentioned, is [LSDJ](https://www.littlesounddj.com/).
+This is basically a tracker or sequencer for the sound hardware in the Game Boy.
+Using external hardware, it can either sync on incoming MIDI signals or output MIDI notes for other devices.
+For the other way round, playing the Game Boy using incoming MIDI notes, the [mGB](https://github.com/trash80/mGB) synthesizer can be used.
+
+The hardware to interface with these is called [Arduinoboy](https://github.com/trash80/arduinoboy), but I used the [ProMicroGal](https://github.com/thikness/Arduinoboy-ProMicroGal) fork with an ATmega32u4 that can interface to MIDI devices via USB, so I left out the hardware MIDI interface.
+You can get (backwards-compatible) GBA link cable sockets from [AliExpress](https://www.aliexpress.com/item/1005006358075502.html).
+To easily be able to solder them, I ordered the GB-BRK-LINK-B PCBs from the [gb-hardware](https://github.com/Gekkio/gb-hardware) repo.
+I also was lazy and used [pio to build the firmware](https://github.com/xythobuz/Arduinoboy-ProMicroGal/commit/aa66eabc54f39b34d05347ec0711d3e2e204d3c8).
+
+<!--%
+lightgallery([
+    [ "img/gb_mod_5.jpg", "Front of ArduinoBoy" ],
+    [ "img/gb_mod_4.jpg", "Back of ArduinoBoy" ],
+])
+%-->
+
+To run LSDJ or mGB you can either use a [EEPROM cartridge](https://www.aliexpress.com/item/1005006294370333.html) and write the ROM to it with a [USB programmer](https://www.aliexpress.com/item/1005007652321830.html), or get an [Everdrive](https://krikzz.com/our-products/cartridges/edgbx7.html).
+Unfortunately they are really expensive, so I got a [chinese clone](https://www.aliexpress.com/item/1005007560023741.html) (that is unfortunately no longer available, but you may be able to [find others](https://www.aliexpress.com/w/wholesale-game-boy-cartridge-micro-sd.html)).
+It works fine with all games I tested and also both LSDJ and mGB.
+
+<!--%
+lightgallery([
+    [ "img/gb_mod_3.jpg", "Chinese Everdrive clone" ],
+    [ "img/gb_mod_2.jpg", "Screenshot of Everdrive-clone menu" ],
+])
+%-->
+
+And it's great fun, all [GB](https://archive.org/details/Cyles_Gameboy_roms) and [GBC](https://archive.org/details/CylesGameBoyColorRomPack) games ever released come in at less than 2GB combined 🕵️