Shine the light
Projectors are extremely simple devices; light is shone through the object that you wish to see, in this case the images from the cartridges. This is then shone through the lens, magnified, and finally projected onto the wall. This means that they have very few electronics inside of them. There are many more projector technologies, and some of the latest use lasers! Yup, we can now fire lasers at our home. These projectors are not like the one which we tore down; rather, the lasers project the shapes using wireframe.
You can also find cheap HDMI projectors – typically restricted to around 800×480 resolution, but they will scale down a 1080p signal – for around $70 on Amazon. These projectors also use LEDs to project the video/image. Because of their low power they need almost total darkness to work, but they’re cheap, and easy to modify, so we’re sure that someone out there can hack them into a useful project!
At the lens end of the projector we have a small fan that is there to keep the unit cool, but is nowhere near the LEDs that project the light. As for the LEDs, we have four 1 W LEDs, commonly used in torches (aka flashlights for our American readers). These LEDs are focused through a thick lens, and this gives us the best beam of light possible for the projector. To rotate the inner lens used to magnify the projected images, we see a low-speed, high-torque DC motor. The motor and LEDs are directly connected to the power, and there are no other electronics in place to control the projector. But, for those of us with the equipment, we could easily sneak in a Raspberry Pi, Arduino, or ESP32, and the appropriate buck converter (LM2596 to drop 12 V to 5 V for the boards) and motor controller (L298N would be ideal), so that we can control the projector using a web interface or sensor to trigger the projector to life!
This is a simple, fun projector. It has very few electronics, but plenty of space for us to add to it. The unit is water-resistant, but not for use in downpours, as the seal will ultimately fail. The cartridges are easy to open, and grant us the ability to make our own images, meaning we can truly make this our own! For £20, the ‘4 W’ projector is a bargain, while for £30, the 6 W version will produce a brighter and clearer image while retaining the ‘hackability’ of the unit we tore down