lighting LED when lm3914 driver has 0V signal

[anchorman]

I’m trying to figure out how to make an LED come on when my input signal to an LM3914 is effectively 0. Is there some way to do this by hooking up a logic gate or transistor to pin 1, and having it light up an LED when pin 1 is off?

The messy part with this is that when the chip turns on the output pins, it grounds the positive LED supply through the chip, so the 3914 is not giving a normal logic state as an output (so far as I can tell).

The other complicating factor is that I want my source voltage to be 14.4V (nominal 12V power in my car), so interfacing with logic chips that use 5V signal is messy.

My other thought is to hang an extra comparator chip on the signal coming in to the LM3914 led display driver and set it to come on when signal voltage is below a few mV, turning off the “0V” led indicator when the signal is high enough to light the first LED on the LM3914, but while I was waiting for those parts to come in, I was exploring other methods.

Is there any way to get an LED to light when there is effectively 0V signal without extra comparator?

[anchorman]

Somehow I poked around long enough using iCircuit that I managed to make this work out. It was pretty frustrating putting it into action until I realized that the collector and emitters were reversed on the transistors when I was putting everything onto the breadboard. but now it works!

using random MP2907A pnp transistors salvaged from an exit light I pulled out of the trash. in real life, the input to the first transistor is taken through the 10k resistor to pin 1 of the LM3914. without the 10K resistor, I’m thinking that the base flows current to ground and essentially presents a short across the LED that pin one is supposed to be switching. when that pin 1 is off, the first transistor is in cutoff, and the second is in saturation. when pin 1 is turned on, it puts it into saturation and then cuts off transistor 2. so I guess I made an inverter/not gate. very handy.