Introduction: Colander Effect Lamp Using a Magnifying Glass

About: Openproducts' focus is on design of new products and on innovative approaches towards improving existing products. An example: the CountClock, a concept facilitating children to learn telling the time. Purpose…

This Instructable shows how optics creates a colander effect from an LED spotlight. To set the scene a colander is used as a lampshade, but the real trick applied is a magnifying glass, resulting in a pattern of light spots under the lamp. This gives an effect as if the light shines through the holes of a colander.

Safety warning: in order to reduce heat generation in this project it is important to use a low-energy LED spotlight.

Step 1: Optics

The large picture shows how the rays of light travel from the individual LEDs in the spotlight through the magnifying glass to the opposite surface. The magnifier does not only swap left over right, but it also exchanges the upside for the downside. This is irrelevant for the colander effect lamp, but it’s good to know, for example if you like to use the magnifying lens to make projections or if you use multicolored filters. Note that the translucent green and red bricks in the picture are only for demonstration purposes: they highlight the paths of the rays.

Step 2: Shopping List

To make a Colander Effect Lamp you’ll need the following parts:

  • A colander for the lampshade;
  • An LED spotlight. Make sure to choose one with many individual light points, because together these will make up the colander effect, as the light spots will be projected to the opposite surface;
  • A socket that matches the LED spotlight;
  • A strain relief to pass on forces to the sleeve of the cable, in order to spare the electric connections;
  • A magnifying glass;
  • A stud bolt that matches the size of the magnifier glass grip (not pictured above).

Step 3: Colander Lamp

A colander lamp can be easily made: put a socket and a colander together and ready you are. It’s a funny design because you’re replacing the lampshade by an object of a similar shape but with a different function. Depending on the bulb type used, the effect of spots may be projected on the surrounding walls in the room, but not on the surface under the lamp.

And that is exactly what makes the Colander Effect Lamp different: its distinguishing feature is a magnifying glass that adds a spot pattern under the colander lamp, as will be explained further below.

Step 4: The Socket

You’ll need an LED spotlight and a socket that matches its screwcap. In this Instructable a porcelain E27 socket was used and its internal connector was replaced by a GU10 socket, thus matching the LED spotlight. It’s better however to use parts that do not need to be modified. Here the GU10 socket was glued onto the E27 ring (it’s needed to keep the socket in position when screwing in the bulb).

Another important criterion for the socket is that it allows to clutch onto the colander.

Step 5: Fixing the Colander

Make a wide hole in the bottom of the colander. Use for example an old screwdriver and a hammer to shape the hole. Place the socket in the hole and screw it together.

Step 6: Fixing the Magnifier Glass

To keep the magnifying glass in the right position a stud bolt is used. The nuts allow to fix the magnifier. The stud bolt should be smaller than the grip of the magnifier to allow drilling a hole into it. Here a 4 mm (0.16 in) hole was made to fit an M4 stud bolt, and the grip has a diameter of 8 mm (0.31 in).

Step 7: The Colander Effect

The light of the individual LEDs in the LED spotlight travels through the magnifying lens and is focused on the surface underneath the lamp. The pictures show the points of light on a round table.

Step 8: What’s the Point of It?

The Colander Effect Lamp is an original way to bring light into a room. There’s one application that may be functional though: the points of light may be used as a free interpretation of a game board for playing Ludo (United Kingdom) or Parcheesi (North America).

Step 9: Another Project With Dots of Lights

If you read this Instructable down to here: thanks for your interest!

When you’re fascinated by dots of light you might also like another Openproducts project, the CountClock. The device is shown in the picture and in the animations above. The CountClock is designed to assist young children in learning to tell the time: the confusing concepts of an analogue clock (the double scales and double hands, the numerals (or their absence), the half hours and quarters) are all decomposed and offered as separate learning steps, tuned to young children. Multi-colored lights indicate time on separate hour and minute scales. Just by counting one can read off time. The first animation (the top one in the series of the three animations above-right) shows what the learning level 'Quarters' looks like.

The device is user-programmable, so original concepts of indicating time can be designed, such as a rainbow (second animation above) or a tidal mode (third animation). More info on the open source CountClock concept and the tidal mode can be found in the series of Instructables, available at: (published January to August 2018).

Step 10: Stay Tuned

If you’d like to be informed on new work by Openproducts, feel free to follow and share via social media (via Twitter and FB You might also point people to the Instructables gallery by Openproducts or point them the CountClock website Openproducts also has a webshop at


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