oscillophone :D

[littlefeller]

found this, amazing
http://www.instructables.com/id/Oscillo ... cilloscop/

[BladeRunner919]

That's pretty cool. I have been looking at buying a cheap oscilloscope but I do like making stuff so I could see myself having a go at this.

[therealdb1]

I took the easy route and purchased a very nice Hameg twin beam scope on eBay for £20 which has far superior specifications to the smartphone adaptor shown in the link!
Keep your eyes peeled and you can buy digital storage scopes for about £50 sometimes.
Of course you do not get the enjoyment of buiding it yourself but then you can always use it to develop and build something else.