Facial Expression Detection & Light Control

I'm in need of a program to monitor the facial expressions of people in front of a camera. The program should be able to detect when one, two, or three people are present, and then analyze their expressions. If all of the individuals are smiling, I want to activate a light positioned next to the camera.

Key requirements:
- The system must be built using Python as the primary programming language.
- It must be capable of real-time analysis, with minimal lag.

Ideal Skillsets:
- Proficient in Python for image processing
- Experience in facial recognition and expression analysis
- Knowledge in real-time data analysis and control
- Familiarity with Raspberry Pi cameras and hardware integration

Delivery:
- The final deliverable should be a working program that can be easily deployed on a Raspberry Pi with a camera attached, the program should provide real-time facial expression analysis and control a light source based on the conditions mentioned above.