Perhaps you’re right. When my son tried this out with me, he turned away where he couldn’t see what I was shining the light at. This was done using my Convoy S2+, purchased from Bangood. This is the only flashlight I have with this particular driver, and it has the standard 3/5 mode firmware. It does have visible PWM on medium and low.
It doesn’t occur with any of my other flashlights, including the two Qlite equipped flashlights I have. They both have the NLITE firmware.
I have uploaded a video to Youtube. I used a calendar with red and white colors. My hope was to show what my son and I have observed with my Convoy S2+, featuring the stock 3/5 mode firmware. This light’s medium mode whine is much louder when shined at a red surface at close range.
You may need to crank up your volume to hear it, as my iPad’s video quality isn’t the best.
Thanks for sharing scooby214.
At full volume with headphones on, I can hear it. Interesting.
When on red the whine is clearly audible
Spooky, can't think of a reason..
It must have something to do with the frequency of red light and the frequency of the light’s PWM. While visible red light probably isn’t the same frequency as the PWM of the light, they may share a harmonic.
Scientifically, it’s interesting. In usage as a flashlight, it’s a minor annoyance. I’ve seriously considered ordering another driver from Mountain Electronics and swapping it into the S2+. That would get rid of the low mode flash, and allow me to disable mode memory.
Definitely the same driver board, ( Nanjg 105c series ) with the Q-Lite Revision Firmware that has the Moonlight mode with Low, med, High using the 4th star group on the board. Its my favourite of the 105c series drivers. It comes with 8, 7135 / 380ma chips, giving a 3.04 Amp for great output.
I have used many of them in my modded lights, even some with reduced number of 7135s for good runtime in smaller lights.
I just ordered 10 of them from here:
The color and hum thing sounds interesting. It was mentioned that the light has to be pointed at the color. LED's can generate a small amount of current when light is pointed at them. So maybe certain colors can reflect back the right frequency and amount of light to get through the phosphor layer to cause the led to generate some juice.
the q lite is the upgrade for the stock 105C
stock settings on a 105C are
- 3 mode no flashy sos or strobe ..100% hi 30% med and 5% low
-2 mode hi and low 100% and 10%
- 5 mode just like the 3 mode above with sos and strobe
- 3 mode .. hi /low/ strobe 100%/ 5%/strobe
some drivers will have the order different as well
low / hi/ strobe
or
hi /low /strobe
Some other choices are... memory or no memory
http://www.fasttech.com/product/1186301-8-amc7135-2-group-25-modes-led-flashlight-driver-n
this one has 2 modes
a 3 mode/no sos or strobe.... and the normal 5 mode ... which you can switch back and forth between the two modes by turning the light off quickly after the light flashes when on low .....not a bad idea but kind of a pain that the light always flashes once after being on for 5 seconds on low.