Synopsis: We built motorized LEGO cars powered by small DC motors and 9 volt batteries.
Age Group: Elementary Aged
Prep time: several hours
Budget: around $50 for a program with 12 children attending
9 volt batteries
3D printed axels (to connect gearbox to LEGO axel)
Lots of LEGOs (especially wheels and axels)
I wired and soldered all of the electronics ahead of time, because this process is not safe for children. Begin by soldering the wires to the motor leads. Then solder one motor wire to a lead on the switch. Solder another motor wire to the battery clip connector. Solder the other wire from the battery clip connector to the other switch lead. Refer to the picture for the final result.
Next insert your 3D printed axels (mine are blue in the picture) onto your gearbox axels. Then insert LEGO axels into your 3D printed axels. Connect the 9 volt battery and turn on the switch to see if it all works. Refer to the picture for reference.
Now use glue dots to place a couple of LEGO pieces on top of the gearbox, on top of the battery, etc. These LEGO pieces will serve as the starting point for kids to build and connect other LEGO pieces to make their car. Also make sure to use glue dots to position the battery. Refer to the picture for my final outcome. Yours may look a little different and that’s fine.
When the program began, I placed all of the wired motors and batteries on a table, so that children could grab one and get building.
Encourage children to be as creative as they want. Many of the kids in my program built some interesting looking cars! We even set up some ramps using cardboard and wooden blocks, which was a big hit.
Conclusion: This program was a hit. I would grade it as a B+/A- based on the enthusiasm and interest level of the children. I allowed each child to take their pre-wired motor, battery, gearbox, etc. so that they could continue to build at home. The only downside of this program is the expense of materials and the time spent soldering, 3D printing, and putting things together.