Traffic light – a simple electronic kit


Quite new things can sometimes be made from old electronic devices. This is an instruction for a simple electronic kit for children or for complete beginners, who will thus become familiar with the process of manufacturing and wiring a circuit on a printed circuit board. Basic things that you can find at home will be enough for this.




A CR2032 coin cell battery case is found in every computer.




I saved colored LEDs and switches from other electrical waste.



For production, we will need a case for a button cell battery, LEDs of different colors, switches and a piece of clean printed circuit board.


Traffic light electronic kit scheme


Let's lay out the layout of the parts according to the diagram. This is a parallel connection to the battery poles, with each branch interrupted by a switch.



We will prepare a clean printed circuit board and adhesive tape.




According to the size of the parts and their distribution, we cover the places that we want to remain conductive with adhesive tape. The letters covered by the marker should also remain, but I left it etched too long and they were too thin, so in the end there was nothing left.




Dip the printed circuit board into the etchant. Ferric chloride is usually used, but it can also be another iron, acid or base that can etch the metal. I only had a small amount of etchant left, so I poured it only on the surface of the board.




After some time, the etchant will dissolve the copper that was not covered by the tape. Covered areas will create conductive paths for electrical current. We remove the adhesive tape from the flat joint, wash and dry it. According to the spacing of the legs on the components, we drill holes, install and solder the components. Attention, LEDs only conduct current in one direction. Be sure to check for correct polarity before soldering.



Traffic light – a simple electronic kit for kids

Front page with parts. Orientation is designed for left-handed people.



Traffic light – a simple electronic kit


Finally, I glued a plastic prism on top with three holes that resemble a traffic light. You can also use wood. It looks simple, but the entire production process can take a relatively long time. I wish you a lot of fun.