# Projectors Projectors are simple gadgets in principle: Take a display source (like HDMI) and render it on a transparent LCD, take a light source (like a powerful LED) and shine light through the LCD, and use lenses/mirror to focus and project. [Keystone correction](https://www.cnet.com/tech/home-entertainment/what-is-keystone-correction-for-projectors-and-why-you-should-avoid-it/) is an extra nice-to-have. HDMI carries audio as well, so projectors often come with built-in speakers which are usually not of great quality. Some projectors can be operated using an infrared remote. But projector manufacturers needlessly complicate this by bundling in "smart" features like WiFi, BlueTooth, built-in Android (which is outdated and cannot be upgraded) to deliberately reduce the product's life. And it is almost impossible to replace parts for longevity of the product. What is frustrating is that these resources could have been spent on aspects that actually matter: display resolution, lamp brightness and build quality. Here are some resources for a DIY projector. * [DIY Perks: Building a TRUE 4k home cinema projector](https://www.youtube.com/watch?v=YfvTjQ9MCwY) * [DIY Perks: DIY Smartphone projector](https://www.youtube.com/watch?v=FKL9_bdtHq0) * [Pocket Projector built using a Raspberry Pi](https://www.mickmake.com/products/piprojector-1-x-series-documentation/) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://www.isfixable.com/electronics/projectors.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.