My 10x / 30x microscope and my 2 GigaSample/Second oscilloscope are my two most cherished tools. Without my microscope, there is no way I could possibly hand solder 0603 caps and 0.5mm pitch TQFP ICs. Without my oscilloscope, I would be completely blind to electronic signals transitioning a billion times a second. This link isn’t my exact scope, but it has similar attributes. I REALLY wish I had bought the more expensive 4 Channel Owon scope – but oh well – make due. My largest FPGA PCB is 2″x2″ so a small scope like this is perfect for SMT assembly. Boards larger than 6″x6″ would require a scope with a boom extending arm like this.
My friend DaveP built a custom iPhone4S to microscope adapter so I could take incredibly clear digital pictures using my iPhone’s 8MP camera. The adapter is a $1 piece of PVC pipe with a carefully measured slit the iPhone slides into at the exact right distance from the eyepiece.
For $10 I purchased a micrometer slide that allows me to measure down to 0.01mm.
I dropped and broke the Keyfob to my car the other day, using my microscope I was able to solder the small SMT switch that was shocked loose from the impact.