Mini flash with optical slave

Normally each year around christmas I will be involved in a couple of Secret Santas and one of them is a "all hand made" type where buying the gift is not allowed. Some very creative gifts have showed up!

Turns out I had to come up with something for a photographer... being one myself I know there are many usefull things to make but many are expensive or take a decent amount of time to build.
In comes a mini slave flash with an optical trigger!

Like many projects things don't tend to run to well on schedules so I deadbuged the circuit of a disposable camera flash so it would fit inside the case and have room for the battery (nope, didn't happen!). Here is the circuit diagram for the flash from Sam's repair faq.

In order to squeeze the battery inside of the case everything needed to be small and well laid out. Unfortunatly the transformer is what ultimately stop my from my goal. I had to come up with a small and simple trigger for the flash unit. Provably too simple if used in broad daylight, but i works reliably in bright artificial lighting.

Three components make up the trigger. This conects directly to the trigger pins of the flash circuit.

Here is a side view of the little flash unit.

And another from the back. The beam pattern is maybe a bit too wide but it'll do!

And a size comparison to a comercial flash unit.

So what could it be used for? Small spaces, highlights, inside objects... lots of uses!

The person I gave it too seemed to enjoy it quite a bit. I hope he can find a use for it.