In this instructable a slide projector with an electrical power consumption of 195 W is being rebuild to function at 18 W (corresponding to 91% energy saving). As a result, the light yield of the bulb has reduced by 95%. However, since the luminous power in the original state is far above what is required for atmospheric lighting, the new state of the slide projector is perfectly suited for use in the evening, when it's getting dark. The modification is completely reversible, it will not affect the slide projector's state (see also step 1 on safety). All pictures in this instructable show the case of the modified projector.
The diapositives used in this instructable show paintings by the Dutch painter Vincent van Gogh (1853–1890): 'Landscape at Twilight' (1890), 'Farmhouse with Two Figures' (1890) and 'The Langlois Bridge' (1888).
Core of the rebuild is to replace the 150 W (24 V, 4500 lumen) halogen bulb by a 14 W (12 V, 205 lumen) halogen bulb. Initially the plan was to use a powerful LED instead, but this didn't work out well. The highly concentrated, powerful and uniform light that a halogen lamp provides is key for creating a nice lighting effect with a slide projector.
Another major improvement is that the cooling fan that was required for the 150 W lamp could be replaced by a much smaller and thus more silent fan. This modification makes the slide-projector particularly suitable for use in a living room.
Note that the slide projector used is a conventional device based on a light bulb with an incandescent filament, placed in the focus point of a lens and a reflector. It might work with a modern LCD-based projector as well, but it's not sure that this can be done in a reversible manner. Moreover, the advantage of a slide projector is that the mechanism to hold the diapositive is in place already.
Safety warning: both in the original setup as in the modified state the fan is required for cooling the lamp. Cooling will remain absolutely required, also in the new layout with the less powerful bulb. Omitting the fan will most probably result in a fire. For this reason the device should never be run unattended and supervision of a knowledgeable adult is required. See also step 1.
In the last steps of this instructable two previous openproducts lighting projects have been displayed: the Giant Ceiling Light (step 7) and the Wooden Light-rail (step 8). Step 9 documents the innovative aspects of the Low-power Slide Projector and step 10 addresses licensing issues.
Step 1: Safety and Risk of Fire
For powering the cooling fan preferably use the same transformer to make sure that the fan is automatically on when the light is on.
If a temperature sensor is in place (usually close to the lamp) it can be integrated in the circuit powering the lamp. This has not been shown in this instructable. Note that this measure makes the setup safer, but continuous supervision remains required.
Step 2: List of Material
If it is not important to keep the slide projector intact it is also possible to take out the lens and mirror of the projector. This will result in a smaller installation dimensions. From the slide projector only the lenses, reflector and the holder of the diapositives are being used.
- a slide projector and slides
- 12 V 14 W halogen bulb (or similar*) including a socket
- a cooling fan: low power, low noise (and low voltage)
- a transformer to power the halogen bulb (and the cooling fan)
In this instructable a modified halogen desk lamp was used as a lighting source.
* The modification works fine as well with a 5W halogen bulb (9 W including transformer and fan, resulting in 95% energy saving). Cooling remains required. It is strongly discouraged to use bulbs with higher power rating because of the risk of fire, see also step 1.
Step 3: The Original Setup
An alternative approach is to use a dimmer-switch for reducing the energy consumption of the slide projector. This however was not successful: power consumption was reduced to 50 W at almost no light emitted.
Remove the lamp from the projector to start rebuilding the projector (see next step).
Step 4: Installing the New Bulb
Attach the transformer to power the bulb. Do not yet switch on the light as the cooling fan first needs to be installed properly. See the next step.
Step 5: Installing the Cooling Fan
Step 6: Hide the Projector
Step 7: Other Lighting Objects by Openproducts: UFO Lamp
Step 8: Other Lighting Objects by Openproducts: Wooden Light-rail
Step 9: Innovative Aspects
1. Replacing a high-power lamp in a slide projector by a low power lamp leaves its functionality intact (albeit at lower light yield) and reduces electricity consumption significantly;
2. Replacing the noisy built-in cooling fan by an external silent fan reduces the noise and makes the projector suitable for continuous use in the evening;
Important to note however is that the original safety measures such as temperature sensor and fuse are being bypassed, which makes cooling an important aspect. The modified projector requires constant supervision of a knowledgeable adult. See also Step 1 on safety.
The next step elaborates on the license type chosen for this instructable.
Step 10: License
Republishing this instructable in a non-commercial venue under that same license is allowed, provided it is being attributed properly (cite the name openproducts, link to www.openproducts.org, https://www.instructables.com/member/openproducts, or the original Instructable.
For other arrangements send a Private Message through the instructables member page (https://www.instructables.com/member/openproducts). Openproducts is open to agreements on innovative business models for commercializing the low-power slide projector.
If this design infringes any rights then refer to Article 28 in the Terms of Service (https://www.instructables.com/tos.html).