Experiments with Tiny LCD projection

Mobile phone LCD

LED Focus Light with Driver

Cardboard Lens Housing

• Since a long time wanted to build a small projector like the ones on instructables.com. It seemed tougher than it actually is.
• Basically the idea is to rip apart the reflector and the LED/tube portions of an LCD and just use the glass. The glass without the backlight works as a slide, in front of which there is a lens for magnification and a powerful light for illuminating the slide.
• LCD: After multiple trials, breaking different LCDs, found an old mobile a Videocon  V1293 which has a resolution of 128x128 in 1.44 inches and comes with a 3GP player. Managed to remove the casing without damaging the glass. As seen in the LCD pic, the white plastic casing is the rear part of the LCD housing and a portion of the reflector can still be seen.
• Lens: 
• Tried various lens from local shops, but reasonable quality lens are available from scientific equipment shops. Vasa Scientific in Malleshwaram has some choices. Got a 75mm dia 25cm FL, 50mm 10cm FL & 50mm 5 cm FL lens. Current projector uses the 50mm/10cm FL.  Cost under 100 INR.
• A fresnel lens is necessary to collimate the rays from the light source. It makes sure a point light source becomes wider and uniform. They are available at stationery shops. But one has to ask for page magnifiers that look like a scale, else the usual answer is a shake of the head. Depending on the size, for a 10 inch by 3 inch,  the cost is around 45 INR. This lens has not been used cos the LEDs came with focus lenses.
• Light Source:
• Metal Hallide bulbs are usually used for projector and they get hot.
• The idea here was to use LEDs. Illumination did not have to be great so as to be visible in day time. Vision in a dark setup was ok. 
• Got 3W high power LEDs from Om Electronics in SP Road along with an LED driver. One has to be careful here as they get very hot and the heat has to be dissipated. The 3W LEDs are from ProLight and roughly around 200 lumens/LED.
• Many ways of heat dissipation were considered:
• TO get a computer processor heat sink, apply thermal compound and paste these LEDs and then drill them down to the heat sink. This was all too much work and there were no tools to do the same.
• Luckily got a LED focus light with 3x1W LEDs and a driver and the enclosure at a local light shop for 200INR. Initial trials were done with 3x1W illumination and then finally desoldered these LEDs and changed them to 3x3W LEDs with the other LED driver. The enclosure comes with its own lenses that narrow down the light. After desoldering had to apply thermal compound to make the new LEDs connect to the LED heat base. Even though the area for dissipitating heat is smaller the heat sink gets slightly hot. Plan is to add a computer fan to cool it further.
• Assembly
• Cardboard was used to make the projector assembly. Could try with plastic, etc at a later point in time.
• Content conversion
• Used ffmpeg to convert movies to 3GP format to play on the mobile. The 3GP player looses audio sync very often. A few samples from the Super cartoon series and Family guy are shown. 
• Magnification
• The image was roughly 1.5 feet for a distance of about 7 feet.