How Does a Reverse Peephole Viewer Work?

by | Learn

Last Updated on June 2, 2021

A peephole allows you to look outside from the inside. George Winningham invented the peephole in 1932.

The best reverse peephole viewer, as the name suggests reverses the effects of a peephole. It means you can see inside from the outside. It works as the viewer’s lenses reverse the effect of the peephole’s convex lens. So by using a peephole you can see who is knocking at the door.

How Do You Reverse a Peephole?

To make a reverse peephole, you should insert the lens of the peephole in such a way that it faces the inside of your home. Then, you should insert the viewing piece of the peephole in such a way that it would face outside. You should push the viewing piece towards the center of the door until it fits tightly.

How Do You Clean Door Viewers?

peephole

Since a peephole allows you to see who is knocking at the door you should keep your peephole clean.

  1. Soak a cotton swab in a glass cleaner and clean the interior side of the peephole with it.
  2. You can use a glass cleaner and a paper towel for cleaning the exterior side of the peephole.
  3. Then, you should look through the peephole to verify that everything is clearly visible and there is no moisture or streaks on the lenses.

Can you see both ways through a peephole?

Whether you can see an eye or camera someone is watching. If there is no light source on the other side it may be harder to tell. To see if it goes all the way through you may sometimes also go and check the other side of the wall the peephole is in.

How Does a Reverse Peephole Viewer Work?

A reverse peephole viewer reverses the effects of a peephole. That means it allows you to see the inside from the outside. The viewer’s lens reverses the effect of the peephole’s convex lens. These peepholes are pocket-friendly and easy to fit. (1)

What do you call a peephole in a door?

A peephole in a door is also called a spy hole, peek hole, door hole, or door viewer. It is a small opening through a door that allows an individual to look from the inside to the outside. 

Alternatively, a reverse peephole allows an individual from the outside to the inside.

Can You See in a Peephole?

You cannot see from the outside to the inside from the door peephole.  You can see outside, but outsiders cannot see inside. A standard peephole is a very simple structure with just two lenses at either end of a tube. On the other hand, the iVision Intercom is a wireless video unit than the standard analog peephole. It also uses a small camera so there is nothing to look through. (2)

Which Lens is Used Indoors?

We use a concave lens also called a diverging lens in the wide-angle peephole indoors. This lens acts as a door viewer’s lens and is a small opening through a door that allows you to look from the inside to the outside.

Why is it Preferable to Use a Door Lens?

A peephole is made up of convex lenses.  It allows you to see who is on the other side of the door. So, you can use it for security reasons. For better visibility at night, it is preferable to have a door light outside the door. 

How High Do You Install a Peephole?

The height at which you want to mount a peephole is an important factor to consider while installing a new opening to the outside. It can vary from house to house, but the average height to install a peephole is between 4 and 5½ feet from the ground. Anybody who would open the door should be able to look through the peephole.

How Do You Look Through a Door?

peephole

To look through a door, grab a small reflective surface. The idea behind this is to use the reflection to peer through the bottom of the door. You should kneel down next to the door you wish to see under. Place the reflective surface flat on the ground, which is next to the door gap. Then, look at the edge of the reflective surface that is closest to the door.

How much does a peephole cost?

A handyman will charge between $50 and $55 to install a peephole. It includes labor and material cost. But you can save money by buying the device for $18 and installing it yourself.

Frequently Asked Questions

Are peepholes always required?

Peepholes are not always required. In most societies, the owner is not required to provide tenants with doors that have peepholes and chain locks. However, many societies have adopted the Uniform Building Security Code that requires a peephole for doors in newly constructed buildings.

Do doors come with peepholes?

Peepholes come in two parts – lens and sleeves. First of all, drill the door hole, and then insert the lens from the inside. Thereafter insert the sleeve from the outside, and then screw them together for a peephole. With fiberglass, metal, or composite doors, use a standard bit. 

How do you remove a peephole from a door knocker?

For removing a peephole from a door knocker, grasp the inside part of the peephole with the needle-nose pliers and apply pressure to the outside lens using a couple of fingers. Then, turn the pliers anticlockwise to loosen the inside piece from the rest of the peephole assembly. Finally, remove both ends from the door.

Bottom Line

A reverse peephole viewer reverses the effects of a peephole. It allows you to see in from the outside. It works as the viewer’s lenses reverse the effect of the peephole’s convex lens. So by using a peephole you can see who is knocking at the door. Thus, peepholes are used for security reasons. 

References

(1) convex lens – https://www.synopsys.com/optical-solutions/learn/optics-for-kids/lenses.html
(2) Vision Intercom – https://www.bhphotovideo.com/c/product/1002902-REG/optex_i_vision_ivision_2_way_wireless_video.html

About Gadgets Spy

Hi, I’m Michael, a security and surveillance expert. I co-founded and write for GadetsSpy and help teach people about new tech and Gadgets.