Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Musical greeting cards are usually a battery, piezo speaker, switch, all wired together on a piece of board with black blob on it. The 'blob', is a C.O.B. (circuit-on-board), in this case a programmable device. The COB is simple and cheap to manufacture, and tough to rip off...
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