Help! I want to build a electronic circuit for science fair. Ideas?

I am building a electronic project for science fair. I am skilled at building electronics circuits. I want to build something amazing but easy enough to be understand by people who do not know electronics.
Example:
Power bank or cellphone charger
LED Paradise
.
.
Please Help me!

I have the perfect project for you -- a cloaking device: https://www.electronicproducts.com/News/Mercedes_uses_LEDs_to_create_invisible_car.aspx

It has been done, sort of, but that is obviously inferior work. I am sure you can do better.

Please let us know how it turns out.

John

Sound (hand-clap, whistle etc) -activated flashing lights?

Or basic and amazing detectors like in www.techlib.com/electronics
- batteryless AM radio (Crystal radio)
- static charge or cloud charge detector
- Lightning detector
- Line noise detector
- ion chamber
- electric field detector produced by car's tyre or honey bee
- two transistor siren generator
- single or two transistor AM radio etc

Ideas: https://www.crystalradio.net/

I made a spark gap radio transmitter like Guglielmo Marconi did. A un-tuned transmitter is very simple.
I used a crystal receiver.
Sent code 2 feet.

ronsimpson said:

I made a spark gap radio transmitter like Guglielmo Marconi did. A un-tuned transmitter is very simple.
I used a crystal receiver.
Sent code 2 feet.

Click to expand...

Felt interesting to know how actually Marconi discovered the radio technology. Are there any detail (but basic) description just to see its operating concept.

But Tesla discovered it before Macaroni, didnt he? His tesla oscillator functioned in much the same way as Marconi's spark gap transmitter.

(misspelled on purpose-hehe)

Willen said:

Felt interesting to know how actually Marconi discovered the radio technology. Are there any detail (but basic) description just to see its operating concept.

Click to expand...

It has been 50 years ago that I read a book on Marconi. I think he was at the kitchen table. His transmitter was made of two frying pans. A battery gave power to the pans. One was positive and one negative. The handles were pushed together to where the voltage would spark across. I think the receiver was also two frying pans with the handles almost touching. Sparks flew. (probably my memory is a little off)

He was not the first to do this. The transmitter/receiver was not tuned to a frequency. He did not call call this "radio".
Also see; James Clerk Maxwell, David E. Hughes, Nikola Tesla