Your Smartphone Can Make 3D Holograms!

Well everyone, the future is finally here. I'm going to be showing you how to turn your smartphone into a 3D holographic display, where you can turn any 3D file into a hologram that can be viewed in three dimensions from any angle. In order to understand how this is working, first I need to introduce you to a concept called persistence of vision. Persistence of vision is the phenomenon where an image continues to appear in your vision for a fraction of a second after exposure to the original image has stopped. I can show you that your brain does this using this white ball here. So if I turn on the lights in this ball, it turns kind of a purplish color here. But I can assure you that there isn't purple lights in here. There's actually three different lights, a red light, a green light, and a blue light. And what's weird is there's actually only one light on at a time. The green one turns on and then off, and then the blue one turns on and then off, and then the red one turns on and then off. None of them are actually on at the same time. But the reason we see them all on at the same time is because the stimulation of the visual system is faster than the time it takes for the cones to stop responding to the stimulus. So if the lights are flashing fast enough, you'll see all light colors at the same time, even if they were never on simultaneously. So these lights are blinking faster than your brain can even reset the images. But that's only because they're all blinking in the same spot. If I change the location they're in when they blink, then the light signals won't overlap. So if I spin it, now you see each individual light blinking, and the light signals don't overlap because they're blinking at different spaces, so they hit different spots of your retina. This ability for the brain to retain an image even after the signal is gone is what will help us make our 3D display. This is just a cylinder that has a strip cut out of it. In the center, you can put a phone with an image on it. This strip makes it so that we can only see one strip of the screen at a time. But that's okay because I'm going to spin the whole thing so that the strip sweeps across the screen, and we'll see the whole image. And because of persistence of vision, if we spin it so that the strip sweeps across the whole image in less than about 100 milliseconds, then our brain will just think we saw a normal image and not strips of an image. So why go to all this work just to see an image on a screen? Well, because with this setup, you can stand anywhere around the cylinder and see the image. So it becomes an omnidirectional display. And what's neat is that it doesn't need to be a still image. You can display a video as well because the strip is moving across the screen fast enough so you can still see the individual frames of the video. So this is my omnidirectional video display that I showed in a previous video. I also called it an and a trope based on the guy who discovered it. After I made this video though, I got an email from a guy named Peter Pjanic. He told me that he has a way to use the same setup that I have here to actually view objects in 3D instead of just a flat image that looks the same no matter which direction you look. He called it a parallax multiview 360 degree display. And it's actually not that hard to do once you have this setup here. So let's go back to an individual picture like this. All we do is instead of displaying a constant picture, we update the picture with a slightly rotated view of the picture on the screen. Then we do that again and again. So this will make it so that on your screen there's a rotating figure. But now if you rotate your phone and the cylinder at the same rate as the image on your phone, then depending on where you're standing, you'll see a different view of the object. Let me show you. Look how cool this is. Finally, I can make a real 3D display at home. I can think of so many applications of a display like this. And what's cool about this is it's really not that hard to make. Let me show you all of the pieces to make this at home for yourself. But before we continue, let me tell you about today's sponsor, Odoo. With Odoo's website builder, you can build your own website to elevate your brand in minutes, totally free, with hosting and support included. This is my website, which I made with Odoo. Odoo makes it super simple. Your first app is free for life, and they even include a custom domain for the first year. No hidden costs, just a full website builder that gets you online and growing your brand completely free. And the setup is lightning fast. Just a few clicks and you're good to go. With Odoo's drag and drop tools, there's zero coding needed. You can customize everything exactly how you want. And Odoo's chat GPT integration helps you craft and polish your text effortlessly. Odoo doesn't just give you the tools, they back it up with unlimited hosting and support, so you're never on your own. So if you're looking to boost your brand and create a professional online presence, try Odoo by clicking the link in my description. Now let's get back to our experiment. Now I want everyone to be able to try this if they want. So if you wanna do this too, all you need is a smartphone and a turntable. You can buy a turntable exactly like this on Amazon for less than $30. This is just a mini pottery wheel. And it's nice because you have a knob where you can precisely adjust the speed of rotation. As for the cylinder, I'll put the 3MF file I made for my setup here. I have it big enough for two phones to slide in. That was in case I didn't wanna spin it as fast so I can get twice the frame rate. But you can just use it with one phone as well. You may have to play with it so that your smartphone exactly fits in it though. Now what about the spinning image? Well, Peter was kind enough to make a URL that has the rotating images on it. I'll put a link to his webpage where you can get these rotating images. And that's all you need. Now the hardest part about this setup is syncing the rotation of the image with the rotation of the cylinder. If they don't match exactly, your image will start to rotationally drift. This kind of ruins the whole effect because you can just look at a rotating 3D image like normal on a phone. So you have to be very precise with setting the rotational speed. You'll likely have to adjust to every few minutes as well. There's a lot of solutions to this, but one of them is to use a synchronization LED sensor that corrects for the drift. There are a few other problems that can arise as well due to the refresh rate of your screen. I'll put a link to his paper that describes this in detail and solutions to these problems. And thanks for watching another episode of the Action Lab and we'll see you next time.