tl;dr
I recently built a MBC5 4mb flashcart that had built in rumble, What really caught my eye was the fact that it didn’t need a AAA battery to make the rumble work. At first I thought it was going to be really weak but turns out its just as good as the battery powered rumble carts. This got me thinking…. could I transplant that part of the circuit into the original rumble game and do away with the battery. Join me below to see how I pulled it off.
Hardware
- M1 – Vibration Motor
- Q1- BC817-40,215 SOT-23 PNP transistor
- D1 – SD103AW SOD-123
- R1 – 30kΩ 0603
- R2 – 15Ω 0603
- 0.25mm/30AWG solid core enamel wire
PCB
I’ve supplied the files for the PCB, I got mine produced in the 0.6mm thickness to keep the whole design as thin as possible. All the parts should be hand solder able, You could also use a hot plate and solder paste.
Installing the PCB
Once everything’s soldered into place you can attach the wires to Gameboy cart. The photo below is from a Pokemon pinball game cart. If yours is different you will need to look for VCC, GND and Rumble pads on your cart. These can easily be found. The GND should be the easiest, Look for any exposed square pads on the board, Use a multi-meter to check it is GND by touching the far right pad on the edge connector. For the VCC you need to follow the trace from the far left pad on the edge connector. The Rumble point might be harder to find but you will need find the MBC5 mapper chip then find the pin 26, Pin one starts at the dot on the chip. You can ether just solder to that pin or find a resistor that is connected like in the photo below. I used 0.25mm/30AWG solid core enamel wire to connect to the point on my build but any wire should work.
Preparing the rumble cart
The first thing you are going to need to do is remove the battery connectors since we wont be needing them anymore. Get your iron nice and hot and make sure the solder is flowing, You will need to pull these connectors out to each side because they have clips holding them top and bottom. This is all that you will need to remove, My board in the photo ready had parts removed for spares.
Shell
So I was hoping that my board would fit in a 3d printed shell the same height as a normal shell but the vibrate motor had other ideas. I had to get my thinking cap on and design my way out of this one. I decided to make a cutout window and have a cover you could glue on top. I wanted to be able to use my fill label cart design so we wouldn’t have to reinvent the wheel when it came to making labels but instead I made the cover the same size as the original label as a compromise. I also used the screws off the original cover.
Video
Files
3D print files – https://www.printables.com/model/564284-battery-less-rumble-cart
PCB Files – https://github.com/facelesstech/battery_less_gameboy_cart_rumble/tree/main/kicad_6_files/gbc_rumble_board
Facelesstech 
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