This is a very simple project that I created using three parts.
a) an old part of a tool (probably for connecting cables) which consists of a plastic base and a strong spring.
b) a medium sized bottle
c) 1m led tape with adaptor
Step 1: Spring-bottle connection.
At first I inserted the spring in the bottle, so that they cannot disconnect easily. The spring is quite strong and can keep the bottle in a steady position.