The goal of this project was to create a simple badge that Cub Scouts (ages 7-10) could put together. All of the parts needed to be simple two or three wire through hole parts, with clear labels and orientation marking (after testing this with a group of cubs, there are some changes I need to make to improve orientation notation). The cubs started by learning the basics of soldering (SAFETY, SAFETY, SAFETY!), as well as the names of the different components and what they do. Resistor value codes can also be covered. An online simulation of the circuit allowed them to see how the circuit works, and even play with some of the parameters to see how changing the values of the resistors and capacitors can affect the behavior of the circuit (surprisingly the cubs I worked with had a lot of fun with this, even though I only had one laptop to show the whole group of nearly 20).
View an online simulation of the circuit here (screenshot below).
Screenshot of the simulation. Component values can be edited by double clicking on the part.
Assembly time of the badges for kids this age varied quite a bit, but everyone was able to complete them after the third 1.5 hr meeting, so if you do plan to do this with a group make sure you have something for the kids who finish early to do! Overall, the kids were very happy with this project, and I got a lot of positive feedback from them, as well as from their parents.The Build
I recommend attaching the pin clasp first, as this requires a LOT of heat and solder. Make sure you have plenty of solder on your tip, and if you have replaceable tips, put a larger flatter tip on at least one soldering iron to make this easier. The rest of the components can be assembled in any order. Put the battery into the holder last. If all goes well, throw the switch and the eyes should start blinking!The Design Process
To achieve the organic shape of the wolf, I started in Inkscape with an image of a cub scout scouter badge. After tracing the image to convert the bitmap to a vector, I cleaned it up a bit to separate out the outline and the details. I decided to use three different colors: Black Soldermask, White silkscreen, and soldermask holes which show the bare FR4 below.