It’s been a while since I did any work on this project, but I pulled out the components the other day and started to look into the Bluetooth connection between the Raspberry Pi and the Feather 32u4 Bluefruit LE board.

It turns out to be complex and on the whole not very well explained how to make these devices talk to each other.  In the final analysis it’s not actually that hard – but you have to do a lot of reading and educate yourself about Bluetooth LE (low energy) before you can actually Make Stuff Happen (TM).

And when you do there are a few limitations that you have to get your head around – like very small data packets.  So no sending long strings for instance.  And then there’s Services and Characteristics and Notification.  Most documenation is far to low level.  Or, if it’s higher level, then it’s vague and poorly explained.

Anyway.  Two days later and I have absorbed – almost – enough Bluetooth LE lore to be able to start to do useful things.  I have achieved connection and data transfer and am working on creating a service that will ultimately allow the Raspberry Pi to send enough data to the Feather board that it will be able to work out how to update the Neopixel strip to correctly reflect current speed.

Progress is happening.