Hi! At last a micro-engineering question! Micro-engineering is basically designing and making anything useful that has components that are less than a mm. It includes micro-sensors like accelerometers which tell your car when to set off an airbag, pressure sensors, micro-gyroscopes like the ones you get in the i-phone etc. and even electronic noses that can detect gases. I design and make new micro-devices and I have to do this in a clean room because if any dust gets on my little machines it can stop them performing properly – or even stop me being able to look at them through a microscope because the dust or fibre is bigger! I could go on all day – if you have a more specific question get it in quick and I’ll try and answer