So lets think what we need for our replacement logic Board.

First of all. We need a Brian for the Board.

I choosed an Espressif ESP32. Because of the small space inside the Bike light we need to take care.

Thats why i choosed the smallest possible board for the Mikrocontroller. The ESP32 Pico D4

The Advantages of this Microcontroller:

- Wifi - it comes with an easy to use Wifi Stack

- BLE: Bluetooth. You may use Bluetooth and BLE

- Dualcore: You have 240 MHz Dualcore: So more than enough for a bikelight

- a ultra low Power ULP Co Processor

Now the downside of this Microcontroller are: 

- It is not easy to solder by hand.

- limited space: Only 4 Mbytes of Space

So how can we get around these downsides.

Recently a lot of PCB manufacturers offers nowadays Soldering of the boards as well. This helps you to break the hassle of soldering such small Reflow devices.

For my needs this is a perfect solution.