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| The Bangle.js 3 (on the right in the image) looks significantly more modern than its predecessor (left). |
The Bangle.js 3 is shaping up to be an interesting alternative to conventional smartwatches, combining a more contemporary round design with open-source software and hardware designed for experimentation. Gordon Williams, the developer behind the Espruino project, has shared new details about the upcoming wearable, which is expected to ship in summer 2027. The proposed specifications include a 1.2-inch circular display, a faster Nordic processor, Wi-Fi connectivity, and an unusual Bosch gas sensor capable of identifying certain smells. However, some components remain subject to change before production, and the smartwatch's final price has not yet been announced.
Unlike mainstream wearables that prioritize tightly integrated health services and proprietary software, the Bangle.js family focuses on giving users control over their devices. Its open-source approach allows developers to create applications, modify functionality, and experiment with hardware. The third-generation model aims to preserve those characteristics while addressing one of the most noticeable limitations of the Bangle.js 2: its comparatively basic rectangular appearance.
Bangle.js 3 Introduces a Round Display and Updated Design
The biggest visual change is the transition from the Bangle.js 2's rectangular screen to a circular 1.2-inch display with a resolution of 240 × 240 pixels. The new panel supports 64 colors and sits inside a housing with a metal front bezel. Although the display remains relatively modest compared with the high-resolution AMOLED panels found in many premium smartwatches, its specifications reflect the project's emphasis on efficient operation and practical everyday functionality rather than elaborate graphics.
The redesigned case includes four physical buttons, with one positioned on the left and three on the right. According to the developer, the watch will accommodate the same straps used by the Bangle.js 2, making it easier for existing owners to reuse their accessories. The new model is expected to be slightly wider and thicker than its predecessor while maintaining approximately the same height on the wrist. These changes provide room for additional hardware without abandoning the familiar dimensions of the earlier watch.
Compatibility With Existing Bangle.js Applications
Moving to a round screen creates a challenge for applications originally developed around the Bangle.js 2's 176 × 176-pixel display. To address this, the developer is implementing a compatibility mode that places the older square interface within the new circular panel. Existing applications should therefore be easier to migrate, although some may require adjustments to take full advantage of the additional screen area. The graphics system uses a 240 × 240-pixel buffer, with pixels in the corners falling outside the visible circular display. Native round-screen layouts should ultimately provide a better experience than simply reproducing the older interface.
Nordic nRF54L15 Processor, Wi-Fi, and Expanded Sensors
Inside the Bangle.js 3, the planned hardware includes a Nordic nRF54L15 processor based on the ARM Cortex-M33 architecture, operating at up to 128 MHz. The chip supports Bluetooth Low Energy, while a separate ESP32-C2 component provides 2.4 GHz Wi-Fi connectivity. The developer also lists 32 MB of flash memory. This combination represents a meaningful hardware update for the Bangle.js platform, although clock speed alone cannot establish real-world performance improvements. Application responsiveness, power consumption, and battery endurance will depend on the final firmware and how the various components are managed.
The announced sensor package includes an accelerometer, gyroscope, magnetometer, barometer, air-temperature sensor, and heart-rate sensor. Together, these components could support motion tracking, environmental information, and a range of community-developed applications. Additional planned hardware includes a speaker, microphone, vibration motor, LED flashlight, RGB indicator, and infrared transmitter and receiver. The infrared hardware is particularly interesting for developers interested in experimenting with remote-control applications, while the combination of environmental sensors creates possibilities beyond ordinary smartwatch notifications.
Bosch BME690 Gas Sensor Could Become a Standout Feature
One of the most unusual proposed additions is the Bosch BME690 smart gas sensor, which is designed to recognize certain gas-related signatures or smells. Such hardware would distinguish the Bangle.js 3 from most conventional smartwatches, where sensors typically focus on movement, heart rate, and other fitness-related measurements. Potential experimentation with environmental sensing could make the feature appealing to developers, although its practical abilities will depend on software implementation, calibration, and the conditions in which it is used. It should not be interpreted as a certified safety detector or medical monitoring feature.
Importantly, the BME690 is not yet guaranteed to appear in every Bangle.js 3. Williams explained in the project's official Bangle.js 3 development discussion on GitHub that sourcing the component at a reasonable price remains a concern. If the sensor proves too expensive, the standard smartwatch could ship without it, while a more expensive Pro version might include the additional hardware. This distinction matters because the final product lineup and the availability of the gas sensor have not been confirmed.
Open-Source Software and Repairable Hardware Remain Central
Software flexibility continues to be one of the principal reasons to consider a Bangle.js smartwatch. The platform uses Espruino, an open-source JavaScript environment that enables developers to build and customize applications. Rather than depending entirely on a manufacturer's predefined features, users can experiment with watch faces, sensors, utilities, and other functionality supported by the hardware. This approach is particularly attractive to programmers and electronics enthusiasts who want a wearable device that can serve as both an everyday accessory and a development platform.
The hardware follows a similarly accessible design philosophy. The Bangle.js 3 is planned with a non-glued rear case that can be opened by removing screws, giving users access to internal test points for experimentation and modifications. A four-pin connector concealed behind the upper strap is designed to support charging, SWD programming, debug UART output, two analog-capable GPIO connections, and a switched 3V output. These connections are unusual in a consumer smartwatch and could make the device especially useful for testing custom electronics or investigating software behavior.
Wireless Charging and a Battery of Approximately 200 mAh
The smartwatch is expected to include a battery with a capacity of approximately 200 mAh, broadly similar to the previous generation, alongside wireless charging support. Williams has explained that the integrated speaker occupies a significant amount of internal space, limiting the opportunity for a larger battery. However, the removable rear cover could make future modifications easier. The developer also intends to release CAD files for a deeper replacement back, potentially allowing enthusiasts to experiment with larger batteries and alternative configurations.
Actual battery life remains unknown, and no verified endurance figures have been published for the finished smartwatch. Although newer processing hardware may offer efficiency advantages, the final runtime will also depend on display activity, wireless connectivity, sensor usage, and application behavior. Water resistance is another consideration: the developer expects the case to tolerate rain and everyday contact with water, but swimming is not recommended. An official water-resistance certification has not been established, so prospective buyers should avoid assuming the watch offers the same protection as dedicated swimming or sports wearables.
How Does the Bangle.js 3 Compare With Conventional Smartwatches?
The Bangle.js 3 is unlikely to compete directly with premium smartwatches on every specification. Devices designed around advanced fitness tracking, standalone navigation, and contactless payments generally prioritize features such as integrated GPS, NFC, and more sophisticated health-monitoring systems. The currently outlined Bangle.js 3 hardware does not include integrated GPS or NFC, which could limit its appeal to runners who want phone-free route tracking or buyers who regularly make payments from their wrists. Its modest color display also places greater emphasis on practical information presentation than on rich visual interfaces.
Its advantages lie elsewhere. Access to software, physical hardware connections, a removable case, and compatibility with community-developed applications provide opportunities that are rarely emphasized by closed smartwatch ecosystems. The addition of Wi-Fi, infrared hardware, environmental sensors, and a possible gas sensor could also support projects that conventional wearables are not designed to accommodate. For buyers primarily interested in fitness coaching or integrated mobile services, a mainstream smartwatch may remain more suitable. For developers seeking flexibility and customization, the Bangle.js 3 offers a different set of priorities.
Bangle.js 3 Price and Release Date
The Bangle.js 3 is currently expected to begin shipping in summer 2027, although that remains a target rather than a confirmed release date. Williams has indicated that a pre-order campaign is likely, but only after sufficiently finalized pre-production units are available and manufacturing timelines become more reliable. Pricing has not been finalized either. The developer expects the new smartwatch to cost slightly more than the Bangle.js 2, but has not provided an exact figure or confirmed whether separate standard and Pro models will be offered.
With its circular display, expanded connectivity, accessible hardware, and continued focus on open-source development, the Bangle.js 3 represents a substantial evolution of the project. Its long-term appeal will depend on how well the new hardware performs, whether the existing application ecosystem adapts to the round interface, and which proposed sensors make it into production. For now, the watch is an intriguing upcoming option for developers and enthusiasts, but prospective buyers should treat its specifications and availability as preliminary until the final design is announced.
Source: GitHub