I was asked by a friend to create an enchanted rose prop for an upcoming production of Beauty and the Beast, and I agreed. It had to have petals fall off with an RC controller, and enchanted lights. Not to be outdone by existing models that can be found on the internet, I created my own petal dropping mechanism from scratch and very soon regretted doing so.

The base of the flower head: the levers snapped onto the bars and their string went through the holes underneath.

The base for my rose was a fake rose from the craft store. I removed all the petals and designed and 3d printed little pegs to put on each petal. These petals were then put into the head of the flower, which had six little levers to pop the pegs out. These pegs were pulled by fishing line run down along the stem and to a set of servomotors in the base of the prop.

The competed electronics mounted in the base

The flower mechanism built. Just pull on one of the strings and the petal falls out!

In the end I found that my mechanism was not as robust as I needed and the size of the petals made them interfere with each other and not fall. Faced with a time constraint I chose to reduce the number of petals to three, using every other spot. This way the petals did not touch each other, and allowed the rose to function the way it was intended. However, I did not have time to finish programming and attach lights.

In its limited final capacity, the use of a microcontroller became unnecessary, but I did not have time to take the base apart and attach the servos directly to the RC receiver.

Oh and after the show I found out that one of the mechanisms broke on opening night and the crew went the whole week using two petals

Overall a mediocre success.

The electrical components, all held in a 3d printed base, consisted of:

• XIAO-form microcontroller (SAMD chip): controlled the servos and the lights

• RadioLink T8S/R8EF pair to tell the XIAO when to drop the petals or turn on/off the lights

• 6x SG90 servomotors to pull on the strings and drop the petals

• 2x DC/DC converters: took two 9v batteries and converted them to 5v for the servomotors and 3.3v to power the XIAO

Circuit board with the XIAO, DC/DC converters, and pinouts