Problem
The native bluetooth menu on macos only displays the first reported battery level from a multi-battery device with no way of viewing the other battery levels. Gauntlet Gauge is a native macOS utility that displays the individual battery levels of Bluetooth devices with two power sources, specifically built for split wireless keyboards where each half reports battery independently.
Overview
Gauntlet Gauge provides:
- Real-time monitoring of both keyboard halves
- A consolidated menu bar display
- Lightweight background operation with minimal overhead
- Notifications on low battery for either device
Design Goals
- Zero configuration after initial device selection
- Minimal CPU and memory footprint
- Immediate visibility of low battery conditions
- Native MacOS
Architecture
- Bluetooth device discovery via macOS IOBluetooth APIs
- Periodic polling and event-driven battery updates
- Status bar UI using NSStatusItem
Challenges
After completing the app, I struggled to get it listed on the app store due to Apple’s rigourous review process. I had to go through a couple iterations with their support team but it was taking a while to get responses.