Connect the projector

1. Cable: best

A USB-C to HDMI adapter (Android phones with video out, iPhone 15 and later) or Apple's Lightning Digital AV adapter (older iPhones). No lag, and sound goes over HDMI to the projector.

Not every Android phone has video out over USB-C; look up "DisplayPort Alt Mode" for your model. Get an adapter with a charging port for long shows.

2. Wireless mirroring

Android: Quick Settings → Cast or Screen cast, to a Chromecast or a projector with Google Cast. iPhone: Control Center → Screen Mirroring, to an Apple TV or an AirPlay projector.

No cable, but 0.1–0.3 s of lag and some blur on fast motion. Fine for mapping; content may run a beat behind the sound on the phone.

3. Second screen (Chrome)

Tools → Project → Present to a screen sends only the output to a Chromecast, a cast-capable projector or a connected display. This device keeps its controls, so nothing you do here is projected.

Videos and images are copied to the screen over Wi-Fi when it needs them; big videos take a while.

4. Laptop

Use the projector as a second display, then Tools → Project → Open output window. Chrome puts it on the projector by itself if you allow window placement; otherwise drag it there and click it once.

When mirroring

  • Everything on the phone screen is projected. Map in landscape, then tap Show: only the content is left. Double-tap to come back.
  • Turn on Do Not Disturb so notifications don't pop up on the projection.
  • The phone is wider than the projector, so you'll get thin black bars at the sides. That's normal.

On the projector

Turn off keystone and auto-keystone, and set the picture to "native" or "just scan" (no overscan or zoom). This app does the correction; the projector's own softens the image and can shift it after you've mapped.

Device check

Paste the report into an issue to record what was tested on which phone.

Find surfaces with the camera

  1. Prop this phone up 30 cm to 1 m to the side of the projector (not on top of it), back camera facing the set. Further to the side tells surfaces apart better.
  2. Dim the room lights. Check the preview shows the whole projected area.
  3. Tap Start and don't touch anything for about half a minute. The projector shows stripes; tap the screen to cancel.

Photograph the set from the projector

  1. Hold this phone right beside the projector's lens, as close as you can, back camera facing the same way as the projector.
  2. Leave the room lights as they are. Check the preview shows the whole projected area.
  3. Tap Take the photo and hold still for a few seconds: the projector goes black, then white.

Line up the photo

Drag the four corners onto the corners of the projector's picture in the photo. Everything outside them is cut off.