Responsive all purpose bike light

My first thought was this will be a challenging control theory design, for example you enter a dark area and the light turns up, which immediately causes the light to turn down

However a much more serious, and dangerous, risk then becomes obvious - a car approaches with full beam headlights, your light responds by turning off. As a minimum this could cause you to break the law (no front light in hours of darkness).

Potentially this can be resolved with a slower response time before turning down, but equally you will need it to power on quickly if, for example, approaching a tunnel.

Some cars are being fitted with this technology, they are easy to spot as the lights turn on *just after* passing under a motorway bridge on my morning commute

you wouldn't want it switching off when someone is coming towards you with their headlights on full-beam in the dark ... I guess the placement of your LDR will be quite important.

Question: how will you ensure that the light doesn't turn itself off when passing under street lights or past well-lit shop fronts?

Kickstarter is already littered with nice-sounding ideas that have limited appeal or real world use. I wish you well, but speaking as someone who designs stuff for a living, the devil of your use case will be in the detail.

Can't comment on LDR's, but I do like the way that the less powerful Lezyne lights attach to my handlebars with the rubber toggle thing.