This listing offers a replacement board to stealthily update the second generation Apple ADB II ball mouse with an optical sensor. It uses the original ADB port which was introduced with the Apple IIGS, Macintosh SE and Macintosh II and was used until the late 90s. If your mouse has lost its ball or it has stopped working, this board will help get it back into service.

Apple produced several variations of this mouse, so before purchasing, please open your mouse and check if its internal board matches the general shape and internals shown in this listing.

This product is not a USB device, it is intended to be used with vintage machines, though it could be used with ADB to USB adapters if you want a classic ADB mouse with an optical sensor paired with your battle station.

Note: The ADB cable from your mouse is required, and you will need to desolder and solder 4 wires to the new board.

ADB Mouse Shell Compatibility

• ✅ Model M2706 (Made in Malaysia, Manufactured by Mitsumi) - Tested and fits

Features

• Compatible with ADB protocol as a mouse input device
• High-quality optical sensor set to 100 counts per inch (CPI) by default for vintage systems (like the original spec)
• Ability to update CPI via host machine or USB-C serial port
• Ability to adjust speed from a setting of 1 to 6 (5 is the default)
• Buttery smooth mouse movements
• Tested with SE/30, Iici, Quadra 800, and NeXTStation Turbo with ADB port
• Omron switch for mouse button
• Uses original mouse ball retainer
• Easy firmware updates through drag-and-drop of firmware files
• In-house developed device firmware

Included in Your Order

• ADB Optical Mouse board with lens (cable not included)

Installation Instructions

To install the new board, use a soldering iron and tweezers or needle-nose pliers. The original board uses a connector soldered to the board which makes the installation a bit more challenging.

1. Add extra solder to the bottom board side of the wire connector. A low melt solder like Chip Quik is helpful for removing components like this one.
2. Pull the wire out once the solder melts.
3. Clean off any excess solder from the connector end before attaching them to the new board. It may be necessary to trim and strip the wires.
4. Insert the wire gland into the notch, note there is a curved side that is oriented toward the lower shell.

Wire Color Coding

While You Wait for Your Order to Ship

Consider using this time to restore the original color of your mouse shell. A simple method involves placing the shell in a mason jar with OxiClean and leaving it in the sun (the process used on the mouse shown in this listing).

Changing the CPI (Resolution) and Speed Settings

The CPI can be changed in increments of 100 counts from 100 to 1500. The default setting is 100 CPI like the original mouse.

Note: Adjusting the CPI is probably not typically necessary. Increasing the CPI makes the mouse pointer move faster/longer distances on the screen for a given amount of physical movement. It is added as a feature in case someone has a large high resolution display.

There are currently two ways to change the CPI setting:

1. With the Macintosh ADB Parser application. Input the hex value (0x01 to 0x0F) via Listen Register 1 command for the mouse address (usually 3).
2. Connect via USB-C serial connection to your computer and input the number and press return (100-1500). An easy way to connect is to go to Huhn Serial Web Terminal on a Chrome compatible browser to connect to the mouse.

The speed setting, 1-6 is applied in a similar way. A speed setting of 1 is not really a usable setting at this time, it results in unnatural movements. 5 is the default setting. In the serial console, just type a number 1-6. With ADB Parser, you need to enter the speed along with the CPI since it's stored in the lower byte of the 16-bit register 1. So the default setting would be hex value 0x51 (entered as '0051' in ADB Parser) for speed = 5 and CPI of 100 or as another example, hex value 0x32 (entered as '0032' in ADB Parser) for speed = 3 and CPI of 200.

Project Background

This project began several years ago, initially tinkering with an Apple USB Optical Mouse that can output quadrature signals connected to an ADB mouse with wires, followed by an Arduino Mega. Eventually, the focus shifted to mastering the ADB protocol via a USB to ADB project using a USB host shield. Then development circled back to designing an ADB optical mouse solution based on the RP2040, which made interfacing with the 3.3V optical sensor more efficient.