Automation

I am one of those people who just takes a hobby and goes to the limits with it and then looses interest and moves on. So my set up might take the fun out of growing for some, but if you can understand my goal then maybe you can also help me. In order for me to move on to another hobby I need to automate as much of the simple task as possible...

I use the General Hydroponics nutrients line(Floragro, Floramicro, FloraBloom, Rapidstart, etc.) and have to change the soultion each week. I also use the waterfarm dutch bucket system with the reservoir...But it's homemade. I have 2 big reservoirs connected to the tank with the float valve. I use a timer to open and close the connection, and set it up to change back and forth each week. I did have it set up to switch to a new reservoir each week but the nutrients started to spoil premixed for that long waiting to be used.
Anyway now I'm facing the problem of moving the light. I tried to set up a sensor and connect it to the light so if a plant grows and crosses the sensor it will make the light move up, but the shorter plants are getting left behind.

Now here is my question...How can I make a set up where the light is stationary and the plant pots move down, that way the tops of the plants stay equal distance no matter there height?

Using the same type photo sensor you can control the height by rising or lowering the pot using a simple scissors stand.

Exactly. Just hook the sensor upto the adjustable platform as opposed to the light. So when the plant sets off the sensor, the stand lowers until it is clear of said sensor.

A scissor stand! Yes! I can see it in my head now. Thanks!