AC Current monitoring data logger

Hi Everyone, welcome to my first instructable! By day I am a test engineer for a company that supplies industrial heating equipment, by night I am an avid technology hobbyist and DIY’er. Part of my work involves testing the performance of heaters, on this occasion I wanted to be able to monitor the RMS current draw of 8 devices over 1000hrs and log the data to graph the results later. I have access to a data logger but it was already committed to another project and I needed something low cost, so I decided to cobble together this basic datalogger. The project uses an Arduino Uno to read analogue sensors via analogue to digital converter (ADC) and records the data with a time stamp on an SD card. There is alot of theory and calculation involved in designing the circuits, so instead of explaining absolutely everything, I will just show you how to make it. If your interested in seeing the FULL hit then let me know in the comments and I will explain further.”