When wired networking or data connections can’t be made, for reasons of distance or practicality, various wireless protocols are available to us. Wi-Fi is among the most common, at least as far as networking personal computers is concerned, but other methods such as LoRa or Zigbee are available when data rates are low and distances great. All of these methods share one thing in common, though: their use of radio waves to send data. Using other parts of the electromagnetic spectrum is not out of the question, though, and [mircemk] demonstrates using light as the medium instead of radio.
Although this isn’t a new technology (“Li-Fi” was first introduced in 2011) it’s not one that we see often. It does have a few benefits though, including high rates of data transmission. In this system, [mircemk] is using an LED to send the information and a solar cell as the receiver. The LED is connected to a simple analog modulator circuit, which takes an audio signal as its input and sends the data to the light. The solar cell sends its data, with the help of a capacitor, straight to the aux input on a radio which is used to convert the signal back to audio.
Some of the other perks of a system like this are seen here as well. The audio is clear even as the light source and solar cell are separated at a fairly significant distance, perhaps ten meters or so. This might not seem like a lot compared to Wi-Fi, but another perk shown is that this method can be used within existing lighting systems since the modulation is not detectable by the human eye. Outside of a home or office setting, systems like these can also be used to send data much greater distances as well, as long as the LED is replaced with a laser.
world, which could make for some very interesting non-trivial applications.
concerns of privacy and data security; they look less and less attractive the closer you look. Luckily the Raspberry Pi and its friends have improved the accessibility to the point where it’s positively easy to create whatever you want with whatever hardware you need, and to that end we think [Mehrdad] has done a splendid job.
The robot face is introduced to us with a soundtrack befitting Stranger Things, or maybe Luke Million. The build was inspired by The Doorman, a creepy art piece with animatronic eyes. [Jens’] build started with a 3D model of a 3D mask, with the eyes and mouth modified to have rectangular cutouts for LED displays. The displays are run by a Raspberry Pi Pico, which generates a variety of eye and mouth animations. It uses a camera for face tracking, so the robot’s evil eyes seem to follow the viewer as they move around. In good form, the face has a simple switch—from good to evil, happy to angry. Or, as [Jens] designates the modes: “Fren” and “Not Fren.”
