4 ms·
I can spot a Cadillac or GMC vehicle on the road a mile behind it from the flicker of the taillights. It's terrible.
by MPSimmons 8y ago
I can spot a Cadillac or GMC vehicle on the road a mile behind it from the flicker of the taillights. It's terrible.
- timbit42 8y agoWhy do they flicker? Are they AC powered?
- bradyd 8y agoYou can dim LEDs by turning them on and off really fast using a process known as pulse width modulation (PWM). Ideally for something like brake lights you would use a constant current driver to control the light level to prevent flickering. I don't know why GM is using PWM, but I'm guessing they just use a cheap control circuit. I really hate their LED tail lights. Just moving your eyes from side to side is enough to easily see the flashing.
- kurthr 8y agoAlso, due to leakage for large LEDs they are more efficient at higher current. That means that for a given power, you're better off driving them at a higher current for a shorter duration. You can increase the effective luminance without violating the power spec.
- yeutterg 8y agoAgreed. Most car manufacturers' LEDs flicker (just look at any slow-motion video, such as those on Top Gear or The Grand Tour), but GM's are at a much lower frequency that is visible if the vehicle is in motion, or you are in motion.
- nitrogen 8y agoI always wondered if anyone ever tried to encode information into the flicker pattern of LED tail lights. I can think of a lot of uses, good and bad.
- yeutterg 8y agoSome people are talking about using LiFi or high-speed IR communication for vehicle to vehicle communication. Seems like a great idea, but you can do it at a much higher frequency than what GM is doing today, so it's not distracting to humans.