2 minute Optocoupler January 4, 2011 Not much to say about it, all it actually is is a LED and a photo resistor inside a tube of heat shrink tubing. Related Posts 433MHz RF Communication Home Automation – The interface V0.01 Voltage Dividers and Arduino About The Author Mikey Add a Comment Cancel replyYour email address will not be published. Required fields are marked *Comment Save my name, email, and website in this browser for the next time I comment.