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Finalizing PCB design

A project log for BicycleCompanion MINI

Simple but powerful bicycle computer, with nice OLED graphics.

Matias N.Matias N. 07/04/2017 at 22:440 Comments

This week I've bought remaining components so I have now finalized the PCB design. I did many changes and I feel I could go on forever so I decided to stop here and give it a rest.

Anyway, I think that many changes were really positive since I considered how this will fit into the enclosure, what will be the space available for the battery and how things will be connected. First change was to move buttons to underside, where the battery will be. It should fit a 30x40 LiPo cell, which can have 460mAh (at least I have one of that size) and I could simply put several in parallel to improve capacity.

I also decided to remove most connectors (for battery, hall sensor and display) since they were really bulky. The display will be (in the final version) soldered to a flat cable directly to the board, with some extra length. This way you could disassemble the device and have the screen connected. The screen will be firmly mounted against the top cover so I'm not relying on the connector for mechanical support. The hall sensor will be connected via an external stereo connector. This is also a bit better in therms of removability and waterproofness (yes, I invented those two words). Having a connector which needs to go through the enclosure seems convenient but it impedes any tight seal. In any case, in the future I would do this using spring contacts or something like that, but this isn't available here so I decided to leave that for this version. Finally, same concept can be applied to battery (connect via cable connector instead of having a PCB connector) which I think is a bit more space efficient.

I will print the design and confirm how it would be in relation to the display. If everything is okay I will send the PCB for fabrication this week. Then, a long wait before I can do anything.

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