Embedded Systems · In development

Custom nRF52840 Bike Computer

A component-level cycling computer with custom nRF52840 hardware, GNSS, motion and pressure sensing, display, storage, charging, and battery monitoring.

nRF52840AltiumGNSSBQ24074Embedded C

Altium 3D render of the custom nRF52840 bike computer PCB

Objective

The goal is to build a complete bike computer around a bare nRF52840-QIAA SoC rather than a development board, combining sensing, storage, display, USB, debugging, and battery management on a purpose-built PCB.

My contribution

System architecture

Component selection

Schematic capture

Digital interface planning

BQ24074 power-path charger integration

Battery protection and fuel gauging

Automatic USB/battery source selection

USB ESD protection and PCB layout

Design process

I started from the use cases—automatic wake, speed, location, altitude, and elevation gain—and translated them into sensor, interface, memory, display, programming, and power requirements. The PCB is designed to support structured bring-up before full firmware integration.

Technical challenges

The design had to resolve these system-level and implementation requirements.

Bare nRF52840-QIAA SoC

GNSS over UART

Accelerometer and barometer over I²C

QSPI flash and SPI LCD

USB programming and SWD debugging

Protected single-cell LiPo power system

Validation or results

Hardware development is underway. After fabrication, I will validate each power rail and interface, then develop the embedded firmware from scratch and integrate the sensors incrementally.

Images and diagrams

Selected project photographs and design captures. Open any image to inspect it at full resolution.

Top-down Altium 3D render of the custom bike computer PCB — PCB 3D render — custom nRF52840 board with GNSS, display, USB-C, controls, and sensors

Bike computer GNSS, flash memory, barometer, accelerometer, BLE, and SWD schematic — Peripheral architecture — GNSS, QSPI flash, barometer, accelerometer, BLE, and SWD

Bike computer USB-C charging and LiPo power-management schematic — Power management — USB-C input, BQ24074 charging, 3.3 V regulation, and fuel gauging

nRF52840 microcontroller schematic for the custom bike computer — MCU subsystem — nRF52840 power, clocks, RF matching, USB, display, and digital interfaces

Tools and technologies

nRF52840 · Altium · GNSS · BQ24074 · Embedded C

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