Going further
There are a number of modifications that you can make to this project. For example, it is possible to fit a miniature toggle switch into the top cap, alongside the LEDs.
It is also possible to fit the circuit into a smaller case by using a 3 V lithium coin cell. I chose PVC pipe because I find it easier to machine than other materials and through hole components for first-time builders.
The following image is of a much smaller device. Patents and non-disclosure agreements prevent me from showing you anymore; however it is an example of what can be achieved with a little ingenuity.
Small IR flasher
