ASSIST-ME: a SLIDE PROJECTOR DESIGNED FOR WORKSHOP

INTRODUCTION

This project is an example of how an advancement in one technology can give new life to old products. Computer, affordable high resolution printing and bright LED are three technologies that are used in this instructable for giving new life to old slide projector. Let us have a look at the major changes that these technologies have brought to a slide projector,



1. Inefficient incandescent light bulb was replaced energy efficient bright LED.
2. Overall size of the projector was reduced by using small sized LED.
3. Portability and long operating hours without external power source are now possible with energy efficient bright LED.
4. Eliminated expensive and time-consuming photography labs for producing slides by computer and printer helped.
5. Computer allowed archiving of digital data on slides.



MOTIVATION

Diapod is the source of inspiration for the project. But has totally different design from Diapod. Since, it's design is completely different from original Diapod, so it can be made without any issues. Basic functionality, ease of use, robustness, continuous usage capability and other good features are the only things in common with the original product.

It is designed as a tool to assist you in your workshop and hence its name. An all aluminium construction has been preferred and adapted the project to suit harsh workshop environment. Aluminium stock is used to reduce cost and simplify construction. Mostly basic tools are required but very few operations like use of hole-cutting saw might require tools a little more than basic.

Main reason for building a slide projector is its versatility as a tool in a sophisticated workshop. Computer enables one to make highly customized slides for the projector.


APPLICATIONS

Assist-Me can be used for (in addition to the uses of Diapod),



• replacing costly LCD projectors in many cases,
• giving presentations,
• archiving and display of technical drawings, electronic circuit schematics, workshop reference charts, etc. right at your workbench,
• displaying instructions right on the spot,
• projecting grid/cross hairs for different purposes like,

• taking big measurement,
• as markers for placing objects on wall,
• for non-destructive marking of various materials while machining, etc.

Step 1: Tools and Materials

Following tools and materials are required to make Assist-Me.

TOOLS



1. Saw
2. Riveter
3. Steel rule
4. Tri square
5. Craft cutter
6. Hole cutting saw
7. Drill press with drill bits
8. A computer with inkscape
9. Laser printer or any other equivalent printer capable of printing on transparecy



MATERIALS



1. A lens from a magnifying glass (shorter focal length or the one with higher magnification is recommended; this will reduce projector length)
2. Card stock
3. Pop-up rivets
4. 1" Aluminium angle
5. A4 size Transparency
6. Bright white 5mm LEDs
7. 1/2" Aluminium square tube
8. 2 M6 bolts, 8 M6 nuts and 4 washers
9. 3 mm acrylic sheet (transparent CD jewel case can also be used)

Step 2: Concept and Design

CONCEPT

The concept behind Assist-Me is that a static slide projector (the present LCD projectors are dynamic) can be a very useful tool in a workshop if it has certain features. As a result, the following features are incorporated in Assist-Me for making it suitable for use in workshop environment:



1. It is rust-proof as it is built mostly with aluminium.
2. It is shock-proof as it works on a battery. Also charging is done using a 5V charger.
3. It is shock-proof! This time I mean mechanical shocks.
4. It works in daylight. If LED used is bright enough it can even work in direct sunlight!
5. It can be given a fixed configuration by fixing focus.
6. It is portable and economic.
7. It can tolerate dusty environment of a workshop.



DESIGN

Assist-Me design is a little complicated but once the structure is ready it is very convenient and has sufficient space for placing internal components like battery, LEDs, and other things. The basic structure design is flexible that can be used with the different components available.

The complete structure design is provided as two .pdf files. One gives the dimensions of the parts and the other shows the assembly. Internal circuitry and lens assembly is not provided as it is self evident from the photographs. Since, these are the parts depend on the local components available, design of these parts will vary from person to person.

Step 3: Lens and Structure

The lens is held in position by placing a suitable lens in a hole cut in acrylic sheet part using hole cutting saw. The ON/OFF switch is mounted on the structure by cutting a hole using profile cutting saw.

The photographs show stage wise assembly of structure. A stainless steel wire mesh is also provided. This mesh is not only aesthetically pleasing but also provides adequate space for ventilation which allows better cooling of the battery while charging.

Step 4: Light Array

An array of bright white LEDs is used for providing the projector with light. QCB was prepared for the array. A casing of aluminium was provided for reflection of light into the slide.

Step 5: Final Assembly

These photographs show the finished product.

Step 6: Slides

Old slide format (135-35mm; http://www.diyphotography.net/making-35mm-slide-photography-business-cards/) has been followed for the design of Assist-Me. All the templates used are provided in the instructable in .svg and .pdf formats.

A laser printer with transparency as medium was preferred for making slides. The reason being that Assist-Me is designed to be able to bear rough handling and hostile environment of a typical workshop. So do the slides. So a transparency with laser printing is more robust than a gateway sheet with inkjet printing.

The orientation of slide depends on the correct view of the slide by the projector. The slide is to mirrored while before printing and is to be placed upside down. Assist-Me is designed such that it can be placed both in landscape and portrait orientations.

Step 7: Assist-Me in Action

Few applications shown in the photographs are as follows:



1. Presentation
2. Illustration
3. Reference chart
4. Painting
5. Electronic circuit schematic
6. Gear
7. Map
8. Engineering drawing
9. Polar grid for measurement of large objects