Bengala
How to project Halloween on your house
Published October 9, 2026
Short answer. Light one spot, not the whole house. Pick something pale and flat: a window, the front door or the garage door. Set the projector level with it and a few meters back, plug in your phone with an HDMI adapter, and drag the corners of a shape until the picture lands only on that spot. Use an effect that is mostly black. Wait for full dark, then walk to the street and look.
A projector throws a rectangle. A house is full of things that are not rectangles: windows, trim, a porch light, a door set back under a roof. Aim the beam at all of it and you light the downspout and the neighbor’s car too. Mapping stops that. You tell the picture where the door is and it fits itself to the door. The rest of the house stays dark, and that dark is what makes the effect work.
What you need
- A projector bright enough for the spot. The table below has the numbers, and the cheap projector guide explains what to look for on a spec sheet.
- An iPhone or iPad with Bengala, and a USB-C or Lightning to HDMI adapter.
- An HDMI cable, 3 to 5 meters (10 to 16 feet).
- Power where the projector sits. An outdoor-rated extension cord, with the plugs off wet ground.
- A tripod or something solid. Wind moves a stack of boxes.
- Shelter. A porch roof, or a plastic bin with a hole for the lens and the back left open for air.
- Tape for the cables.
If you only have a cheap lamp that throws a fixed ghost on the wall, that is a different kind of gadget. This page explains the difference.
Pick the spot
Choose one thing to light and make it good. Brightness is in ANSI lumens, for a pale surface, and these are estimates.
| Spot | ANSI lumens | Notes |
|---|---|---|
| Pumpkin or hedge | 300 | Small and close. A circle shape fits a pumpkin. |
| Window | 300 | Light comes from inside, through something translucent. See the window guide. |
| Front door | 500 | Tall and narrow. See “Tall things” below. |
| One-car garage door | 1,000 | The largest flat surface you have. See the garage door guide. |
| Two-car garage door | 2,000 | Twice the area. |
| The whole house front | 3,000 | More near a streetlight. One bright section beats a dim whole. |
The surface counts as much as the lumens. Pale, flat and matte is best: cream siding, painted wood, smooth stucco. Dark brick and dark paint swallow light. Rough stucco and brick show every bump when the beam comes from the side. Glass lets the light through, which is why windows get their own guide.
How far back
Distance to the wall is the throw ratio times the width of the picture. The throw ratio is on the spec sheet. Most small projectors sit between 1.2 and 1.5.
| Picture width | Distance at 1.2 to 1.5 |
|---|---|
| 1 m (3 ft), a pumpkin or a small window | 1.2 to 1.5 m (4 to 5 ft) |
| 2 m (6.5 ft), a big window | 2.4 to 3 m (8 to 10 ft) |
| 3 m (10 ft), a front door and its frame | 3.6 to 4.5 m (12 to 15 ft) |
| 5 m (16 ft), a two-car garage door | 6 to 7.5 m (20 to 25 ft) |
| 8 m (26 ft), a section of the house front | 9.6 to 12 m (31 to 39 ft) |
Closer gives a smaller, brighter picture. Farther gives a bigger, dimmer one. If the projector has a zoom ring, use it before you move the tripod.
Tall things
A projector’s picture is wider than it is tall. A door is the other way round. To cover a door 2 meters (6.5 feet) tall, the picture has to be 2 meters tall too. That makes it about 3.6 meters (12 feet) wide, so most of the beam lands on the wall beside the door. You waste light and the gray rectangle gets big.
You can live with it and buy more brightness. Or you can turn the projector on its side. Many cannot run that way, lamp models especially, so read the manual first. If yours can, choose Rotated left or Rotated right under Projector rotation in the editor menu, and the picture fills a tall shape instead of a wide one.
Set it up, step by step
- Put the projector where nobody walks. Straight in front gives the sharpest picture. Off to one side works too, because dragging the corners fixes the angle. A steep angle does stretch the picture, and the far edge goes soft, since a lens focuses on a flat plane. Keep clear of the path to your door. Trick-or-treaters who walk through the beam leave shadows on your effect.
- Level it and set the distance. Use the table above. Turn off keystone correction in the projector’s menu, including any “auto” setting. It shrinks the picture digitally and softens it, and the app already does the straightening.
- Connect the phone. Adapter into the phone, cable into the projector, then pick that HDMI input on the projector. Bengala shows the projector at the top of the Home screen. Keep the phone dry and on power, with the app open. The projector shows your picture only while a project is open, and the screen stays awake while it is.
- Show the test pattern and focus. On Home, tap the projector status, then Show test pattern. A grid fills the wall. Turn the focus ring until the lines are sharp on the spot you are lighting, not on the lawn in front of it. Do this at dusk or later.
- Add a shape and drag its corners. Open a project, tap +, and choose Rectangle, or Circle for a pumpkin. Points adds more corners when the surface is an odd shape. Drag each corner onto the matching corner of the real thing. Zoom in on the phone for the last few millimeters. The picture bends to fit. While you drag, the projector draws a grid on that shape, and about a second after you let go it fades. Keep the corners a finger’s width inside the edge so light does not creep onto the trim.
- Pick an effect. Double-tap the shape and choose one. See the next section for what suits which spot.
- Walk to the street and look. Stand where your audience will stand. Dim? Make the shape smaller or move the projector closer. Light on the trim? Pull the corners in. Phone lag when you drag a corner? You are on AirPlay, and HDMI fixes it.
- Decide when it goes off. Pick a time to switch it off and stick to it. Do not leave a projector running unattended all night.
What to project
Black is not light. An effect that is mostly black lights only the part that moves, so the house stays a house. That is why eyes, bats and ghosts read well on a facade, and a bright full-frame color wash does not.
- A window: Friendly Phantoms (nine cartoon ghosts, free), Behind the Blinds or Shadow Play (both Pro).
- A pumpkin on the porch: Candle Grin, a carved face with a flickering candle. Free.
- A door: Bone Sprint, a skeleton running in place. Pro.
- A hedge: Night Watchers, eyes that open and glance around. Pro.
- A big wall or a garage door: Moon Swarm, bats flapping across a full moon. Pro.
Keep the motion slow. Something that takes ten seconds to cross the door is scarier than something that flashes past.
Free and Pro
You can do every step on this page on the free plan. It gives you one project, which can hold as many shapes as you like (rectangles, circles and a set of free stencils), corner dragging, and a set of free effects. Two of the free ones are for Halloween, Friendly Phantoms and Candle Grin. The catch is a small Bengala watermark that drifts across the projection.
Pro removes the watermark, adds unlimited projects and every effect, and new 3D effects arrive regularly. It comes as a weekly plan, a yearly plan with a 3-day free trial, or a one-time lifetime purchase. The app shows each price in your own currency before you buy.
Neighbors and safety
- Do not aim at the road. A moving picture distracts drivers.
- Do not point the beam into a neighbor’s window.
- Some effects flash or change brightness quickly. If a child or a guest might be sensitive to flashing light, stay with slow effects.
- Projectors get hot and need air. Keep the vents clear and curtains, paper and fake cobweb away from the exhaust.
- A cheap projector is not weatherproof. Keep it under a roof or in a ventilated bin, and never seal it.
- Apple says an iPhone is made to work between 0 and 35 °C (32 to 95 °F). On a cold night, keep the phone somewhere warm, or run the cable in from inside the house.
- Tape cables flat. Children run.
Questions
How bright does the projector need to be?
For a window or a pumpkin, 300 ANSI lumens in a dark yard. A front door needs about 500, a one-car garage door 1,000 or more and a two-car door 2,000 or more. A whole house front needs 3,000 or more, and more again near a streetlight. Many cheap listings print big numbers that are not ANSI lumens, so look for that word.
Can I use AirPlay instead of a cable?
Yes, if the projector supports AirPlay or you plug an Apple TV into it. Expect some lag when you drag a corner, and a softer picture that can show banding in dark glows. Fit the shapes over HDMI, then switch if you must. The AirPlay vs HDMI guide has the details.
Does it work in the rain?
Not out in it. Keep the projector and the phone under a roof or in a ventilated bin, and keep plugs off wet ground.
Do I need internet at the house?
Only to download an effect the first time you use it. Once it is on your phone it plays offline. Download the ones you want at home before you carry anything outside.
How long does it take?
The corners take a few minutes. Plan about an hour the first time for the rest: carrying, cables, distance and focus. The second night is faster.
Can I light more than one thing?
Yes. Each surface gets its own shape, and each shape shows its own effect. See the Halloween house projection ideas for combinations that work.