Hi everyone. I'm trying to help my son with his 7th grade science project. We are testing a model of a geothermal power plant. Basically we will use steam to spin a turbine connected to a motor to make electricity. We would like to connect the motor to some kind of charging circuit connected to an 18650 and then connect that to a USB port to charge a phone just to show a useful application. We can do whatever soldering we need to but I'm not sure of the pieces we will need to charge the battery and output via USB. Any help will be much appreciated.
Having been a judge at my share of High School Science Fairs, let me first congratulate you on having a 7th grader (approximately the onset time of hormonal insanity) who does not have a project based on some perceived difference between genders or which type of music makes plants grow the best.
I take it that you “engine” is somewhere between this
Only US$29.99, buy best Aluminum Alloy Stirling Engine Generator Model Science Developmental Toy sale online store at wholesale price.
and this.
**broken link removed**
Assuming also that you are familiar with the safety regulations at the school concerning projects, you want a nifty demonstration and one that can be understood and explained by the 7th grader (not you).
The battery charger is a bit problematic. On the one hand, it is compelling because one of the few things a 7th grader actually does understand is that their phone has to be charged. On the other hand, a charging circuit has a number of other considerations and, even in the best case, would probably take a while to actually charge a battery making an on-site demo difficult.
I would offer two suggestions.
First, while I am reasonably certain that the output of the generator can turn on a single LED, if it could turn on a string of them, they could be incorporated into a model house or model street lights. Then, and this is important, the 7th grader would have to explain how large and efficient the generator would have to be to get beyond the model and into the practical….you see where I am going?
The second would be to use the generator to power a BLE beacon that could transmit some environmental information or just an advertisement that it is on. The second part of the project is that the 7th grader would have to write the simple app that could tell when the engine was running. If it is a one other thing that 7th graders know, it is that they love their apps.
Ok, more seriously, what is it that the kid is going to demonstrate that he has learned more than say, ye old active volcano?