Using proximity sensor to control motor

Hi,
I’m looking for some help with my project: I need to mechanically control a dimmer switch for a neon light using a motor.

The motor will turn the brightness up or down depending on the proximity of a person to the neon sign. The range needs to me 10cm-5m+

From the reading I’ve done so far I’m thinking I need to use a proximity sensor - perhaps one like this?

http://uk.rs-online.com/web/p/proximity-sensor-ics/1229752/

I’m unsure as to how to make the motor turn gradually / incrementally depending on the distance of the person to the sign - if the person is 10cm away I’d like the motor to turn the dimmer to a fully on position, with the dimmer turning down gradually as the person moves away.

I’d really appreciate any help / tips of where to look for info for this project.

Thanks so much,
Romily

The GridEye sensor is a low-res thermal sensor; it's an imaging device, and not a simple device for a beginner to use.
I wouldn't even really call it a proximity device, because it senses distance based on the relative size of the warmer object it sees.

For simplicity, I'd suggest an ultrasonic ranger module, but they're not always reliable with squishy targets like humans.