Sunlight Detection Alarm with Arduino, How to Build a Fun to Use, Very Inexpensive, and Easy DIY

Most technology Instructables are fun to construct, and often easy to build. This is one that shares those features, but also solves a practical problem we had. To prevent fading of furniture, carpet, and the wood flooring in our foyer, my spouse and I installed one-way blackout shades. However, after installation and use, a problem arose. The air in the foyer began to have a slightly musty odor as no sunlight was coming in. My solution was to build a direct sunlight detector, allowing us to close the shades only when the buzzer went off. On overcast days the shades would stay open, as the direct sunlight would not set the alarm off (we live in the Eastern US, so overcast days are not uncommon). It also meant that we could leave the shades open until we heard the alarm on clear days. The result all the mustiness is now gone and as a bonus the foyer is less gloomy. A quick, inexpensive and winning solution on all counts. The video shows the alarm “in action”.”