After the challenge and the practical work on ChibiOS, we are back on the design of the sphere. As we have already said and thanks to Loki, we are going to use two spheres. The internal one will carry the LED strips, the PCB and the battery. The external will provide a smooth shape.
This latter is not going to be printed. We bought a PVC-injected one. We found transparent balls with a diameter of 18 centimeters in a creative hobbies shop. This way, we maximize the usage of the 3D printer. The internal sphere will have a 16 centimeter diameter, the maximal one the printer is able to build. This gives us a 1cm-margin to place the LED strips.
As there are components on both surfaces of the PCB, we can’t “paste” it on a surface. We designed a sandwich-like support. We also put empty spaces to make the USB connector and the switches available. In the end, the LEDs will be carried by 3D grids which will make them easier to install. We won’t be forced to paste them. This makes the determination of the strips position easier.
Here are a few links to the model (3D PDF viewer required). The design is not completed yet. That’s why you can’t see any grid. We ‘ll see what is technically possible with the printer. There’s no hole for the micro usb connector too. The last point is to build a “system” to carry the battery and determine its precise position.
You’ll see the final version tomorrow.