Except for some old Citroen models car headlights are fixed to the body of the car and don't move with the wheels. So why is it that bike lights attach to the handlebars and not the frame? I first found this to be a problem when biking home after dark on country roads. The roads were gravel with drainage ditches on one side and hillside on the other. One definitely wanted to stay in the middle of the road, but the gravel kept the handlebars, and thus the light, moving about. On the downhill this was especially unnerving.
The effect of illuminating the road from lights attached to the frame is that the light seems to float gently in the direction of travel This is version 4 of this idea of attaching a headlight to the frame. The lights are two LED flashlights from Amazon (about $4 each) the housing is an empty HP printer cartridge; inside is a 3 AA battery pack (wired for 4.5V).
To control the lo-beam/hi-beam array I needed a watertight switch. I found this one, meant for a moped, on Ebay for $5.
I wired the turn signals to hi (both L & R) and the lo the red switch and since it has a horn switch (green), I added the Hornit electric horn (a seriously loud horn: top of photo) just for fun.