Smartphones are fantastic tools for showing off our work, watching movies, or even playing games. Their “big” problem, though, is that their screens are rather small. This means if you want it bigger, you must connect it up to a TV or use a projector. Projectors for phones have been on the market now for a couple of years, but most of the decent ones are quite expensive. So, why not make your own? This video from Matthew at DIY Perks shows us how to build our own “Ultimate Smartphone Projector” from scratch. Matthew first shows us a more traditional DIY smartphone projector. But that type of projector has some issues, which Matthew highlights. Those problems are solved with his rather ingenious periscope-style design.
The more familiar DIY smartphone projector that many of us may be familiar with is simply a shoebox with a magnifying glass. Inside there’s some support to hold your phone, that you might be able to adjust to be able to focus.
The problem with this design, though, is that everything’s upside down and back-to-front. You can fix the upside down problem by locking your phone’s orientation. But that still doesn’t solve the issue of backwards text. Matt’s solution takes this basic design and flips it up on its end. Quite literally. Rather than sitting at the back of the box, your phone now resides on top pointing down. What makes it project out the front is a humble mirror. This mirror flips the image so that it projects the right way onto the wall. The basic parts list is as follows.
Some thick cardSome thin card4 drinking strawsSome thin dowelsA small mirrorMagnifying glass lens
First, a box is made with a hole in the front. This hole is where the lens will eventually go. Inside each corner, a drinking straw is placed. Small holes in the box at the bottom of each drinking straw, allow the thin dowels to be pushed. These become the legs of the projector on which it stands. They also guide the box moving up and down to focus it on the wall. A mirror is glued in place at 45 degrees to the lens.
A thick piece of card is then cut to go on the top of these dowels. A rectangular hole is cut in it so that when your phone is placed on top, you can actually see the display. Be careful with your size here. You want it large enough that as much of your screen is shown as possible but you don’t want your phone to fall through to the inside.
This is, essentially, the whole thing. It works. But, the problem is the phone’s screen not only projects light down toward the mirror, but also off to the sides. This is going to add just enough light into your environment that you won’t be able to see the projection so easily. Matthew takes a leaf out of the large format photographers handbook by making a set of bellows. These will allow Matthew to keep the focusing ability, while preventing light leaking from the phone’s display into your darkened room. He prints out his template onto white paper, cuts it out, folds it where appropriate, then sprays it black on both sides.
With everything assembled, the lens in place, and your phone on top, it’s simply a case of positioning it and focusing it on your wall. Thanks to the mirror, everything flips the way it should be. You’ll want to ensure your phone’s screen is at maximum brightness to make the projection as bright as possible.
Sure, it’s not going to be as good as buying a fancy high end projector. But if you just want something simple and basic that you can make yourself, it’s best inexpensive DIY option out there. And it’s a very simple, but effective, build. It could be very cool for projecting video and images onto subjects in the dark for some photography experiments, too. Of course, if I was going to photograph something that’s being projected, I’d probably go with a Light Blaster instead.
