Experimenting with pinhole / camera obscura

A friend showed me a lens cap with some duct tape and told me he took photos with it.
"But... don't you need a lens? How do you take photos through a piece of tape?"
When I looked up close I saw a tiny hole. My friend told me you can take photos through that tiny hole and showed some of his photos on his phone. I saw some strange effects and was immediately inspired.

I borrowed his lens cap and started taking some photos.
My experience: It's difficult!
You're going to need lots of light, watch out for dust (even though it gives a cool effect on some pictures) and be really creative!

This is a photo I took of my cursor on my computer screen, definitely my favourite.

Dirty mirror :( but also a cool effect!

The chip on my PIN card.

I can't remember what is in this picture, it looks like a honeycomb :D

Want to make pinhole photos yourself?

It's really easy:

1. Take a lens cap and make a tiny hole. If the hole is too big, put duct tape over the hole and make a new hole.
2. Set your camera to manual and have fun! :D

In stead of duct tape you could use silver/gold foil. I haven't tried it out myself, but I think it could give a cool effect to your photos!

What's your experience with pinhole?