What transistor to use in place of QVE11223 opto

Question

In the circuit below, I'm trying to replace the physical switch on the 'flipper opto switch board' (and 'power driver board') with a transistor, controlled by Arduino.

My understanding (please correct where I am wrong, learner here) is that I should be able to use a NPN transistor, with Collector tied to the 12v feed from the fliptronics board. The transistor needs to be able to pass 12V at ~12ma

I have tried using a 2n4401 that I have stock of, and I believe this has a hfe of 80, so I run the 5v arduino output through a 2k resistor, which should pass around 0.25ma to the base? (And be enough to switch the transistor 'on', dragging the 12v feed to the LM339 down to below 5v)

But nothing happens.

Entirely likely I'm making a fundamental error here, but I'm not sure what it is. Any help appreciated.

Answer 1

^{simulate this circuit – Schematic created using CircuitLab}

Peter Bennett is right.

Answer 2

At 12 mA wouldn't work if you directly connect X to Arduino?

Anyway this is what you get by redrawing the circuit without the LED:

^{simulate this circuit – Schematic created using CircuitLab}

Any general purpose NPN should work (BC547, 2N3904).