And to go off of what lampyris said, maybe resonate is the wrong term… Vibrate maybe? As the vibration would propogate into audible sound waves. The design of the light could have something to do with why this one in particular. I don’t have one, so I can’t know for sure, but if the spring isn’t soldered to a pcb on the tail end, kind of how it clips into place like my Olight s15, then that would allow a small amount of movement. Maybe enough to make the noise?
Bonus try:
PWM is off phase for each die because of different values for each to be at the same brightness in a medium mode, and by fluke created a PWM tone by spiking amps through the springs that contract and expand with heat and therefore creating minute air pressure changes making sounds.
This tone could be optimized and then controlled to make music in a special hidden mode.
The solution is relatively near now. However it’s not the heat - or else it would affect all my RGBW flashlights. What is special with the H02 that causes those vibrations?
(It also appears in single color modes btw, and PWM is not off phase)
(Also the easter egg mode works for all RGBW lights and doesn’t rely on this effect.)
It may have to do with the design of the head and its acoustical characteristics. There is the stainless bracket holding the reflector to the frame, the head is hollow, and the emitter is mounted to a shelf dividing the head. If you look at as a cross section, it kind of resembles the design of a speaker. the vibration talked about earlier could then vibrate the body and the shelf causing the reflector to vibrate like the cone of a speaker. The empty air space in the head helps create and tune the tone of the amplified vibrations making a beeping noise.
Each spring has ballanced tension suspending the battery in the body because it is on its side. The battery is ballanced perpendicular to gravity. Hey… I’m trying my best;)
I think the pwm (rapid pulsing on and off) can be heard in this host because the integrated shelf the led mcpcb sits on is vibrating in such a way it is making vibrations in our audible range.
It’s not gravity and not the LED shelf. It was already guessed that it’s a spring. But which and why? What does the H02 have, that most other lights don’t?
When on the intermediate levels the pwm duty cycle is the closest to a “false” sine wave. So this pulse is smoothed into an audable wave form and amplified by the magnet and the spring?
