Controle automatico de bomba d'àgua. http://blog.novaeletronica.com.br/controle-automatico-de-bomba-dagua-pelo-nivel-da-caixa-dagua/
How To Test Electrical and Electronics Components with Multimeter
Learn how to make a spot welder - for cheap with this tutorial. Useful for spot welding and to buy one would probably be upwards of 200 dollars but you can make your own for way less.
Ports (super helpful!!)
Resistor Color Codes
Picture of High Power LED Driver Circuits
Cell Phone Detector Circuit
Schematic Diagrams: Joule Thief
old laptop to digital photo frame...
Different types of #sensors #ECE #EEE