Hacking a LED fluorescent tube

I'm trying to hack a LED fluorescent tube and PWM it with arduino and a TIP120 transistor .
I bought one and disassembled it, basically it's an LED strip connected to a 220v though a LED driver.

I'm trying to bypassing the 220v LED driver, and power the LED strip directly from a DC power supply.
I started measuring the voltage on the LED strip when it's on and i got 18v on 2 points.
however when I'm trying to power those 2 points directly with 18v from an external power source without the 220 LED driver i got nothing... :slightly_frowning_face:

i attached an image of the LED strip connected to 220 LED driver...

Does anyone have an idea how can I bypass the 220 LED driver ?

Bigger Image...

Connections for ac and DC are different.
If you have multimeter just put it on buzzer mode and check individually each led by putting one lead of multimeter on one side of led and another lead on other side of led.
This will make led glow, if not change the direction of leads but all with power supply off.
This will give you the idea of. +ve and -ve side of led and then observe the paterrn in which leds are arranged.
Then make your connections.

That LED-strip is very special. It's made with special LED's that probably have anti-parallel dies inside, so it will light up on both half-phases of the mains AC. The "LED driver" is a constant current driver that limits the current into the series-connected string of LED.

You won't be able to use this with your project in mind, sorry.

// Per.