DIY Teleprompter for Your Phone: Three Ways to Build One

If you are new to teleprompters, start with how to use a teleprompter, which covers pace, text size and rehearsal. This post is about the hardware choice. It contains no photographs and no measurements from a build of ours: where numbers appear, they are plain geometry that you can check, and the sizes of your own gear you must measure yourself.

How a real teleprompter works

A studio unit does one clever thing: it lets you read while looking at the lens. According to Wikipedia, the screen sits in front of the lens and usually below it. Its text reflects off a piece of clear glass, or a beam splitter, towards the presenter’s eyes. Light from the presenter passes through that glass into the lens, so the camera sees you and not the text. A shroud around the lens and the back of the glass blocks unwanted light.

The reflection also explains the mirrored text. A reflection reverses an image, so the screen has to show the text reversed for it to read correctly in the glass. Wikipedia notes that the monitors in these units often have their scanning reversed to offset the mirror reflection.

Everything below is a different way of getting your eyes close to the lens. The closer the text is to the lens, the more you appear to be looking at the viewer.

Way 1: a second screen below the lens

The simplest rig is a tablet, a laptop or a second phone placed directly under the phone that records. The script scrolls on that screen and your eyes drop slightly below the lens.

What you need: the filming phone on a tripod or a stable stand, a second screen, and something to hold it at the right height.

Setting it up

1. Mount the filming phone at eye level.
2. Place the second screen as close under the lens as it will go, tilted towards you.
3. Put the script text in a narrow column at the top of the screen, so the words you are reading sit nearest to the lens.
4. Use large text and short lines, so your eyes move down and not sideways.

The honest limit is the eye line. The further the text is from the lens, the more your gaze appears to be off camera. Because it is geometry, you can work out how far. The angle between the lens and the text is the arctangent of the offset divided by the distance to you.

These are calculated values, not test results. They show two things: halving the offset halves the angle, and sitting further back makes the same offset look smaller. If you can step back and zoom in a little, a second screen under the lens can look natural.

Way 2: a glass rig

A glass rig copies the professional design. A pane of clear glass is held at an angle in front of the lens, and a screen sits below it facing up. The reflection of the screen appears in the glass, in line with the lens, and the camera shoots through the pane.

What you need

• A pane of glass or other clear, rigid sheet, held in a frame or clamp at a stable angle.
• A screen to reflect: a second phone or a tablet, facing the glass.
• A shroud, such as a dark cloth or a card hood, to block light from the sides.
• A stand for the filming phone with its lens at the glass.

Geometry: if the screen faces straight up and the pane is tilted at about 45 degrees, light from the screen is turned through 90 degrees, towards the speaker. A glass rig works by that turn.

Mirrored text. The reflection reverses left and right, so the prompter needs a mirror setting. Which flip you need depends on how the screen faces the glass: try horizontal first, and if the text then looks upside down, use the vertical one. Cuelift offers both, and mirroring is part of its free app.

Setup notes

1. Make the pane clearly larger than what the lens sees, then look at the live preview for edges or frames in the picture.
2. Keep the room dim around the pane, so the reflection of the screen is brighter than the reflection of the room. This is the job Wikipedia gives to the shroud.
3. Clean the glass on both sides before you start, because dust shows up in the reflection.
4. Use white text on black. Wikipedia notes that teleprompter text is usually shown this way, for readability.

Glass safety. Treat glass as the hazard it is. The Canadian Centre for Occupational Health and Safety lists cuts and lacerations from sharp edges as a hazard of working with glass, recommends eye protection for cutting and grinding, and recommends gloves and footwear when handling sheets. If you are not experienced with glass, do not cut it yourself. Get it cut to size by a supplier, wear gloves when you handle it, and keep the pane away from children and pets.

Way 3: a prompter app with the reading window by the lens

The third route needs no extra gear. A prompter app on the phone you are filming with scrolls the script in a reading window near the camera, and records at the same time.

Cuelift is our own app for this, and its page describes it in these terms: the reading window sits next to the camera lens, under it in portrait and beside it in landscape on a phone. You set the speed, text size, line spacing and side margins, choose left or centre alignment, and read in white on black or black on white. There is an optional countdown of off, 3 or 5 seconds, and a progress bar and the time remaining stay in view. You can record up to 1080p, and free takes run up to 3 minutes with no watermark. Writing, scrolling and recording work offline, and there is no account.

Because the text is on the same screen as the lens, you do not need mirroring here. The free app still includes mirroring, which a glass rig needs. The Cuelift page in the Store lists what it does and what Pro adds.

Light and distance for each

A general rule applies to all three: if you cannot read a line comfortably from where you sit, make the text larger before you change anything else.

What to avoid

• Mirrored text on a plain screen. It is unreadable. Mirror only when a reflection is involved.
• Long lines. Your eyes sweep sideways across them, and it shows on camera. Keep the column narrow.
• A wobbly pane. A glass that moves by even a little makes the reflection jump.
• Reading too fast. The scroll speed should follow your natural pace. Slow it down until you can pause for breath, and see our guide on reading a script on camera naturally.
• Cutting glass yourself without the right protection. See the safety note above.
• A phone that moves. Stabilise the filming phone first. Everything else depends on it.

Which way to choose

If you only need to read a script and film it, the app route is enough. A glass rig is worth the effort when you record often, want the text to be in line with the lens, and are prepared to build it carefully. For a checklist of what to look for in a prompter app, see our teleprompter app checklist.

Questions

How can I turn my phone into a teleprompter?

Install a prompter app, paste your script and record: the text scrolls in a reading window next to the lens while the phone films you. For a physical rig, hold a second screen under the lens or build a glass rig and mirror the text.

How do I make a DIY teleprompter?

Choose one of three routes: a second screen under the lens, a pane of glass angled in front of the lens with a screen below it, or an app on the filming phone. The app route needs no building, and the glass rig needs the most care.

Why do I need mirrored text for a glass rig?

A reflection reverses the image. The screen shows the text flipped, so that it reads correctly in the glass. Without the flip, you would see backwards text.

Is there a free teleprompter for the phone?

Yes. Cuelift’s free app includes scripts, the prompter, mirroring and recording up to 1080p with no watermark. Free takes run up to 3 minutes. It works offline, with no account.

How do I film on my phone while reading a script?

Keep the phone steady at eye level, light your face from the front, and put the text as close to the lens as you can. A prompter app that scrolls and records together lets one device do both jobs.