PCB making it's a really exciting thing, but when you need to etch, it will be boring if you use ferric chloride (in average it takes 20-30 minutes to be ready). During this time you need to agitate it to speed up the process a bit, but you also need to take care that the ferric chloride didn't spill out.
In this instructable I will present how to build an automatic agitator from an old CD ROM drive quite simply and low cost.
Step 1: The Old CD ROM Disassembly
First, you need an old CD ROM drive which you need to disassemble carefully, not to break anything.