SolarScream

This is a project for teaching kids some basic electronics. I teach a variety of kids in a K-12 on an offhand basis things that I think would be fun to learn. This allows me some laxity in choosing topics that don't bore both me and the kids. It is still amazing to me that we spend so many years in school! The school that I teach at seems really low key and open to funny experiences like showing kids how to use their hands...which seems not a thing anymore. This little project allows them to learn how to solder and glue a small inventive project together and take it home. The basic unit is 3D printed in two parts and the electronics are simple to wire together and teach them about energy conversion(fusion energy-electrical energy-sound energy) and the basics of circuitry, positive and negative wiring, wire stripping and the art of design for 3D printing. The whole project costs under $4.

1. The particular solar panel I used was from Adafruit and provided 5v and 40 ma $3 You can easily substitute much cheaper panels from Amazon or China directly to further lower costs but you may have to modify the design of the top solar panel holder.
2. Gikfun 3v active buzzer. $0.80

This device uses pure fusion power so it should be printed out of PET-G rather than the easier to melt PLA. The upper disc requires support. Choose any colors. I used a Bambu P1S printer--always good.

If you are a teacher and want encouragement on how to build this simple project with your kids there are many tutorials on the web that will ease your learning. The important things are a nice soldering iron and good quality lead-tin solder which is easy to melt. The solar panel is easy to solder to and if you watch the video you will see that the easiest way to use it is to apply a bead of solder to the contact pad before you attach the wire. Kids even in third grade can do this if you want to hold their hands and maintain control over the soldering iron at all times. I often let them add the solder or hold the wire as an extra pair of hands which they really enjoy. The thrill of molten metal and the danger of burning heat makes the whole project more advanced than it is. The buzzers from Gikfun all work well and are easy to solder to. I let the kids strip the wires and wrap them around the electrodes. The plus and minus are carefully marked on these units. I use red wire for the plus and black for the ground to start their learning of circuits. Plus to plus and minus to minus and your done. The wires should be about 2 inches long.

The top of the unit and the bottom are joined with E6000. You can use superglue but there is usually a slight gap between the two sections and it is better filled with the E6000. You should let it dry overnight before proceeding with the rest of the assembly. The kids after finishing with the wiring just tap the buzzer into the lower housing as far as it will go. You than wrangle the excess wire into the center recess and glue the solar cell into position with either hot glue or E6000. The kids seem to enjoy the hot glue more....

Just point it at the sun and it screams! Very easy to use...the shape of the downward facing horn provides incredible amplification of the tiny buzzers output. I clocked it at over 110 decibels! You can easily adapt it to have an on/off switch but really you just turn it over and it goes off.