Arduino Photocell Sunflower for Valentine's Day
Blog Postciricutio teamJune 13, 2017

Today's featured project is actually one that we put together a while ago, While it's going to be a while till Valentine's day rolls around again, this little 3D printed sunflower hooked up to a light sensing Arduino photocell is a charming little creation that will help you make an impression on that special someone in your life. After all, why wait for Valentine's day to be romantic?

In this build, we use an Arduino Photocell to measure environmental light levels which, when triggered by sufficient light will cause a motor to open the sunflower's 'petals'.

Putting it together

This is an intermediate project that is more suitable for builders who already have some experience as well as access to a 3D printer to fabricate the body of the 'sunflower'. The coding work, however, is quite simple and is great for those looking to improve their assembly skills and move up from beginner level projects.

For a full breakdown of the parts you will need as well as all the code required to get the Arduino ready for this project, you can visit our handy tool right here

Customize it

There are a lot of ways to customize and improve on this basic design. If you're an advanced builder you could consider changing the design to make it self-contained, this would need a larger flower model, but with a big enough battery, you could enable this cyber sunflower design to function independently and completely off the grid. To power it, you could place photovoltaic cells on the inside of the sunflower so that it creates its own energy to charge the battery during daylight hours.

The other trick of sunflowers is how closely they track the course of the sun across the sky. While the purist way to deal with that would be to use multiple Arduino Photocells arranged around the flower and have it turn towards the photocell with the strongest result this is both harder to achieve and not as reliable since the sensitivity of the photocells may not be enough for the system to register the changes effectively. But since we know the trajectory of the sun along with the timings of when it rises and sets, we could create a timer based system to rotate the flower to face the sun throughout the day. A hack admittedly, but one that saves a lot of time and still delivers a fairly convincing result.

It will take a bit of balancing to find the ideal balance of size, battery capacity and the number of PV cells needed to make your sunflower energy-independent, but once you experiment a little to find the right balance that works for your location (Since areas with high sunshine and high daylight hours need fewer PV cells) you'll be all set.

Alternative Applications

We hooked up our Arduino photocell to a system to control the opening and closing of our 'sunflower' but there are plenty of great alternative projects you could create using the same light metering photocells. You could create automatic lights that activated in low light conditions and switched off on their own during the daytime. This would be extremely useful for lights that are typically on throughout the night. Or, if you're a morning person you could create a coffee maker that starts brewing first thing in the morning as soon as the rising sun triggers it. And while you're at it, make sure you choose the right capsule with the coffee capsule detector.


If you're looking for something more challenging, you could create automatic skylights that are open during the day to help air circulation and which shut and self-lock at night. Or perhaps automated blinds that are set to perfectly adjust themselves throughout the day similar to advanced sunflower build we described in the previous section?

The Arduino photocell that we've featured is quite a useful bit of kit for every home inventor and has plenty of applications that you could use to make a wide variety of fascinating and practical inventions.

What will you create?

These more advanced projects with articulated movement (even the fairly simple motion demonstrated here) are always a lot of fun to build and we love putting these new creations together in the office. Let us know what you thought of this Arduino build. Did you try it out for yourself? Or create your own build with some interesting modifications, or maybe even created your own unique project using the Arduino photocells to trigger alternative actions ? Why not share some images or videos of your work with the rest of the community in the comments.