A little update to support the existing flashing light to my custom dual motor controller.

It's a simple 24V bulb with a 555 integrated timer and a TIP120 transistor on a PCB (I should have done a photo of the existing PCB...)

It's very simple to use: just apply 24V (DC or AC, a Graetz diode bridge rectifies if AC and allow plug any polarity you want) and the light bulb blinks every 5 seconds or so.

To apply 24V to the light, I used a Grove relay module from seeedstudio connected to pin D12 of the Arduino board.

It's ugly but it works.