What is the difference between Bluetooth vs Wifi?

Linh wonders about bluetooth and wifi, and Dimitri tries his best to explain it… slowly…

References:

• https://en.wikipedia.org/wiki/Bluetooth
• https://www.bluetooth.com/about-us/bluetooth-origin/
• https://en.wikipedia.org/wiki/Wi-Fi
• https://en.wikipedia.org/wiki/Fidelity
• https://en.wikipedia.org/wiki/Infrared

Errata:

• Bluetooth is named after a Viking king
• Wifi: Wireless Fidelity
• Fidelity: faithful or loyal
• Sine or sinusoidal wave
• Infrared is in the nanometer spectrum