BLE allows configuring events intervals - a key factor for optimizing energy use. By tuning these intervals, it’s possible to cut power consumption even further, which is crucial for a charging-free smartwatch.
#BLE #BluetoothLowEnergy #EnergyEfficiency #EmbeddedSystems

I tested the power consumption of BLE connection events on the STM32WB55. Each event draws only 3.29 mA and lasts about 3 ms—a great result for an ultra-low-power smartwatch design. (See attached image for details.)
#BluetoothLowEnergy #STM32 #LowPower

After deeper reconfiguration of the MCU and peripherals before entering STOP mode, I brought it down to under 20 µA. Lesson learned: just enabling a sleep mode isn’t enough - extra tuning and clever hacks are essential for true low power.
#LowPowerDesign #EmbeddedSystems #Microcontroller

When I first tested STOP mode on the MCU (before adding any features), power consumption matched the documentation. But once I added peripherals and some functionality, it jumped to 370 µA.
#CortexM #STM32 #LowPower #Firmware

STM32 also provides a clever setup: two integrated MCUs—one dedicated to BLE, the other for the application. This division helps cut power consumption even further.

The second step is picking the right chip. After research, I found that Nordic and STM32 offer the lowest-power BLE solutions. Nordic is slightly better on paper, but I chose STM32 as I have more experience with it.

#LowPower #STM32 #NordicSemiconductor

Bluetooth is another major energy consumer in a smartwatch. Careful planning here can save a lot of power. The first step: use BLE only, never classic Bluetooth. #Smartwatch #BLE #BluetoothLowEnergy #LowPower #WearableTech

@RobotTalkPod Interesting project. I think that there should be more research in flapping wing robots.

I tested a 10×2.7 mm ERM motor to measure its current draw at different PWM duty cycles. The results are shown in the attached graphic. For typical smartwatch use, this translates to ~0.35 mAh per day
#Haptics #ERM #EccentricRotatingMass #EmbeddedSystems

I continue work on my charging-free smartwatch. The next component to tackle is haptic feedback. Two main options: ERM or LRA. LRA uses less power but needs an extra driver, so I decided to go with ERM. #Haptics #LowPower #Smartwatch #ERM

I chose an ultra-low power Cortex-M3 80 MHz from STM. It offers several sleep modes to save energy when idle. In my real-life tests, it showed just 3.35 µA in STOP mode and 10.18 mA in RUN mode—excellent results for this project.
#LowPower #EmbeddedSystems #CortexM #MCU #STM32

The processor is another big energy consumer. It must be efficient, yet still strong enough for smartwatch tasks. I realise that w/ good software architecture & optimisation, a powerful CPU isn’t needed. Even a Cortex-M <100 MHz can be enough. #Smartwatch #LowPower #CortexM #MCU

In my own tests with a 1.3" MIP display, I measured just 3.4 mA during refresh. Given how infrequently refresh is needed, this means it can consume up to 10,000× less energy than AMOLED!😮
#display #EnergyEfficiency #Hardware #MemoryInPixel #LowPower

I selected a Sharp 1.3" Memory-in-Pixel display. The choice was limited - there aren’t many companies manufacturing such screens.
#Sharp #MemoryInPixel #Adafruit #EnergyEfficiency

One of the most power-hungry parts of a smartwatch is the display. To save energy, I chose efficiency over colours. The options were Memory-in-Pixel (MIP) or e-paper - and I went with MIP for its better refresh rate.
#smartwatch #LowPower #Hardware #TechResearch

I’ve already worked out specific ideas for which technologies to use, which components to select, and how to design the software to minimize power use. The next step is to test these solutions in practice.


#TechDesign #HardwareDesign #SoftwareOptimization

The real challenge in creating a smartwatch that never needs charging isn’t adding an energy source - it’s drastically reducing power consumption. This requires the most effort and true innovation.

#smartwatch #EnergyEfficiency #LowPower

I explored three options for energy harvesting—Peltier cells (body heat), solar cells, and piezoelectric harvesters. The conclusion was clear: only solar cells can deliver enough power to keep a smartwatch running.
#energyHarvesting #smartwatch

To make a charging-free smartwatch possible, two things are essential: drastically lowering power consumption and adding an energy source.
#chargingFree #smartwatch

When looking for a smartwatch, I noticed all of them need frequent charging - sometimes every day. That felt wrong for something meant to simplify life. After months of research, I came up with a concept for a watch that doesn’t need charging. Now it’s time to build and test it.

#smartwatch #chargingFree