Data Transmission Unit
During my first co-op at Lorcan I spent a lot of my time working prototyping with a TI microcontroller to create a network that transmits environmental sensor data. I also tested with solar panels and rechargeable batteries to see if the microcontrollers could operate on solar power in the wilderness. My last project was to design a proof of concept housing for the electronics to show investors.
Design Considerations
- Ingress Protection - Water or moisture will affect the performance of the electronics
- Size - Require a specific surface area to get sufficient power from solar panels
- UV Resistant and withstand large temperature fluctuations
- Electronics need to be secured inside
- Withstand harsh outdoor environments
Solutions
- The overall shape is a pyramid such that the solar panel faces all directions and snow will run off of the enclousure. There is a base and upper housing that gets fastened with three screws.
- The material of the housing was selected to be ASA plastic which is similar to ABS but is much more UV-resistant. Its mechanical properties do not change very much with temperature and can be easily injection moulded or 3D-printed.
- A silicone rubber gasket will go around the perimeter of the device and is compressed using the three screws that fasten the lower housing to the upper housing. Silicone rubber has great mechanical properties at low temperatures and will keep it' elasticity. To seal wires entering the housing from the exterior, cable glands can be used.
- A polyurethane foam is inside the housing surrounding the electronics. This protects it from impacts but also provides some thermal insulation.
- Inside the housing there are several ribs to improve the rigidity and strength of the assembly. There are screw bosses where brackets holding the electronics and battery can fasten to.
Takeways
I learned a lot about product design through this experience by working through the steps of the design process. I did extensive of modelling in SolidWorks. I learned how to do material selection based on constraints using CES Edupack. Last, I had some time to learn about DFM and how to design a product that can be mass-produced. I did this by ensuring all of these parts can be easily injection molded.