SMARTHALO: Turn your bike into a smart one with CFD and electronics
SmartHalo is a smart biking device that pairs with a smartphone and provides turn‐by‐turn navigation right on the handlebar through an intuitive light halo. It also provides a bike locator, a front night light, a cycling metrics tracker and an anti‐theft alarm. CycleLabs partnered with Creaform during the design process of the SmartHalo in order to address the heat dissipation of the device and ensure a robust electronic design. Heat dissipation was studied with a complete CFD model under very severe conditions: 40°C ambient temperature, direct solar radiation, LEDs and drivers operational. A first exploratory design suggested the use of aluminum for the casing to improve the heat conduction from the internal sources to the exterior environment, but this solution was turned down by the radio‐frequency interference analysis. Alternatively, solutions implying thermal potting compound and thermal pads were analysed with the CFD model and proved to be very efficient for reducing the temperature of the critical components. On the electronic side of things, a set of recommendations was proposed to CycleLabs team members in order to optimize the location of critical components on the printed circuit board. Among other things, the RF antenna (Bluetooth), accelerometer, magnetometer (compass) and touch screen were analyzed.
- Recovering of materials thermal properties;
- Contact resistance calculations for solder and thermal paste interfaces.
- PCB anisotropic conductivity calculations;
- Critical internal thermal load definition using measured power budget of typical ride;
- Solar radiation load definition using surface absorbence and reflectance;
- Geometry preparation using CAD software;
- Volumetric meshing using polyhedral cells, prism layers and thin plates mesher for finite volume method;
- Setting of physical models and numerical parameters;
- Test case for parameter validation and mesh independency;
- Simulation monitoring;
- Post‐processing of CFD solutions: visualisation of flow and temperature distribution;
- RF interference vs metal proximity: in‐depth validation of the antenna properties (contacting manufacturer)
- Interference vs metal proximity: analysis of the magnetometer and touch screen design properties.
- Risk analysis: battery maximum temperature analysis vs risks of overheating
- Results and recommendations presentation to the end customer and production of all methodology and substantiation reports.
Tools and Methods Used
Based on the client’s needs, Creaform used the following tools and methods:
- Conjugate Heat Transfer SolidWorks and Altium