Nordic nRF52840
Silent Vibrating Alarm Watch
Overview
A compact wearable smartwatch functioning as a silent vibrating alarm clock without wireless connectivity.
Gavriel BermanSystem architecture
MCU
POWER
SENSOR
ACTUATOR
DISPLAY
- BATTERY → POWERPowerConnects LiPo battery to power management subsystem
- POWER → MCUPowerProvides regulated 3.3V supply to MCU
- POWER → IMUPowerProvides regulated 3.3V supply to IMU
- POWER → HAPTICPowerProvides regulated 3.3V supply to haptic driver
- POWER → DISPLAYPowerProvides regulated 3.3V supply to OLED display
- MCU → IMUI2CI2C communication bus for motion and orientation sensing
- MCU → HAPTICI2CI2C bus to configure and trigger haptic vibration waveforms
- HAPTIC → MOTORPWMDriven motor control outputs for the coin vibration motor
- MCU → DISPLAYI2CI2C display interface for time and UI rendering
Bill of materials
| Part number | Type | Component | Manufacturer | Package | Qty | Datasheet | Match |
|---|---|---|---|---|---|---|---|
| nRF52840-QIAA-R | MCU | Nordic nRF52840 Core processing, Bluetooth Low Energy connectivity, timekeeping logic and alarm scheduling | Nordic Semiconductor | AQFN-73 | 1 | Matched | |
6 alternatives consideredAI verified | |||||||
| TPS63030DSKR | POWER | TP4056 & TPS63030 Manages LiPo battery charging via USB and provides regulated 3.3V power rail | Texas Instruments | 10-Pin QFN | 1 | Matched | |
2 alternatives consideredAI verified | |||||||
| 501230 | POWER | 3.7V 150mAh LiPo Battery Main energy storage for the wearable device | Generic | — | 1 | Pending | |
2 alternatives consideredAI verified | |||||||
| LSM6DS3 | SENSOR | STMicroelectronics LSM6DS3 Motion detection, step counting, and wrist-gesture recognition to dismiss or snooze alarms | Stmicroelectronics | — | 1 | Matched | |
2 alternatives consideredAI verified | |||||||
| DRV2605LDGSR | ACTUATOR | TI DRV2605L Drives the vibration motor for silent alarm notifications with advanced haptic effects | Texas Instruments | Digi-ReelR Alternate Packaging | 1 | Matched | |
2 alternatives consideredAI verified | |||||||
| C1027B002F | ACTUATOR | Coin ERM Vibration Motor 1027 Physical silent alarm vibration generator | Generic | — | 1 | Pending | |
2 alternatives consideredAI verified | |||||||
| SSD1306-470MT | DISPLAY | 0.96 inch OLED Display SSD1306 Time display, battery status, and alarm configuration interface | Shenzhen Lantu Micro Electric Technology Co., Ltd. | SMD,15.24x18.54mm | 1 | Matched | |
3 alternatives consideredAI verified | |||||||
Build guide
5-8 hoursAdvanced
1
Procurement & Preparation
- Source and inspect all Bill of Materials components including nRF52840-QIAA-R, TPS63030DSKR, 501230 LiPo Battery, LSM6DS3, DRV2605LDGSR, C1027B002F, and SSD1306-470MT.
- Prepare the custom printed circuit board (PCB) and stencil for solder paste application.
2
Hardware Assembly & Wiring
- Apply solder paste to the PCB pads and place the core processing unit (nRF52840-QIAA-R), power management IC (TPS63030DSKR), motion sensor (LSM6DS3), and haptic driver (DRV2605LDGSR).
- Solder the 0.96 inch OLED Display (SSD1306-470MT) and Coin ERM Vibration Motor 1027 to their designated I2C and PWM output pads on the mainboard.
- Connect the 3.7V 150mAh LiPo Battery (501230) to the VBAT and GND inputs of the power management module.
3
Firmware Setup
- Connect the SWD programmer to the nRF52840 microcontroller debugging pins on the smartwatch PCB.
- Flash the compiled timekeeping, alarm scheduling, and I2C peripheral firmware (driving SSD1306, LSM6DS3, and DRV2605L) onto the nRF52840 flash memory.
4
Testing & Calibration
- Test current draw on the 3.3V power rail using a digital multimeter to verify low-power sleep state functionality.
- Calibrate the LSM6DS3 gesture recognition algorithm and trigger test alarms to verify TI DRV2605L haptic feedback intensity on the ERM motor.
Document
Silent Vibrating Alarm Watch
A compact wearable smartwatch functioning as a silent vibrating alarm clock without wireless connectivity.
Design Overview
| Item | Details |
|---|---|
| Product Type | Vibrating Alarm Smartwatch |
| Key Functions | Silent vibrating alarm clock, Wearable timekeeping, Internal component architecture visualization |
| Power Source | Li-Ion Battery |
| Connectivity | |
| Size | wearable smartwatch form factor |
| Environment | wearable |
| Difficulty | Advanced |
| Est. Time | 5-8 hours |
System Architecture
Power Topology: USB power charges the 3.7V LiPo battery via TP4056. A TPS63030 buck-boost regulator steps the battery voltage to a stable 3.3V rail powering the nRF52840 MCU, IMU, display, and haptic driver.
Module List
| Module ID | Type | Name | Function | Voltage |
|---|---|---|---|---|
| MCU | MCU | Nordic nRF52840 | Core processing, Bluetooth Low Energy connectivity, timekeeping logic and alarm scheduling | 3.3V |
| POWER | POWER | TP4056 & TPS63030 | Manages LiPo battery charging via USB and provides regulated 3.3V power rail | 3.7V/3.3V |
| BATTERY | POWER | 3.7V 150mAh LiPo Battery | Main energy storage for the wearable device | 3.7V |
| IMU | SENSOR | STMicroelectronics LSM6DS3 | Motion detection, step counting, and wrist-gesture recognition to dismiss or snooze alarms | 3.3V |
| HAPTIC | ACTUATOR | TI DRV2605L | Drives the vibration motor for silent alarm notifications with advanced haptic effects | 3.3V |
| MOTOR | ACTUATOR | Coin ERM Vibration Motor 1027 | Physical silent alarm vibration generator | 3.0V |
| DISPLAY | DISPLAY | 0.96 inch OLED Display SSD1306 | Time display, battery status, and alarm configuration interface | 3.3V |
Key Components
5/7 modules matched to real parts. See the BOM tab for the full component table.
Nordic nRF52840 (nRF52840-QIAA-R)
Candidate 8 (nRF52840-QIAA-R) is the exact match for the primary MPN nRF52840 with a standard reel packaging suffix, man
TP4056 & TPS63030 (TPS63030DSKR)
Candidate 3 (TPS63030DSKR) is the actual IC component matching the primary MPN TPS63030, whereas candidates 1 and 2 are
3.7V 150mAh LiPo Battery (501230)
Rejected weak/wrong-class catalog hits; using web recommendation: 501230
Coin ERM Vibration Motor 1027 (C1027B002F)
Web recommendation: C1027B002F (not in ES)
Build Summary
- Difficulty: Advanced
- Estimated time: 5-8 hours
- Tools required: Digital Calipers, Magnifying Glass, Solder Paste Stencil, Squeegee, Reflow Oven, Soldering Iron
See the Build tab for the full step-by-step assembly guide.
Generated by YuanQi AI Design System · Query: Recreate the exact product shown in the attached image HDwatchinside.jpg, featuring the internal architecture and components of a smartwatch/wearable device.