When Allegra Fullerton got married last November, her niece was the flower girl. Like most her niece was a bit awkward going down the aisle, but Allegra's sister stood in the wings and encouraged her on. What a sweet robot.

Allegra's sister Laurel is "into robots", we're told, and decided to built the flower-blowing bot for her sister's wedding to Andy Fischer. From the pictures it looks like the bot was a hit.

The Flower Girl even took a turn on the dancefloor.

I spoke to Allegra just moments ago. She explained why she had a robot in her wedding:

I have always, always loved robots and have a collection of books, toys, and now an actual robot! How can you compete with a robot crusing down the aisle spitting out flowers on the ground? I wanted my wedding to have a playful feel and pay tribute to my upbringing (Dad and sister are both engineers) and really give a San Francisco feel to the event.

My sister built the robot and has been building robots since she was in high school. The ah ha moment for having a robot flower girl was one sunny afternoon at brunch with my fiance. I had a vision, thankfully he shared it and after a chat with my sister (who was a Mechanical Engineer Grad Student at Stanford at the time) she said she would make it happen and we went from there.

Update! Engineering Sister Laurel writes in with details of the build:

WeddingBot (or so I call it) was built for my sister, Allegra, since she didn't know any young children to act as flower child or ring bearer. I had recently finished building a water-squirting remote-controlled duck boat for a class (details at: http://www.stanford.edu/~laurelf/duck/ ) so she asked me to make her a remote-control robot that would spew flowers.

WeddingBot was mostly designed and built during my internship at Pocobor ( http://www.pocobor.com/ ) a small mechatronics consulting company in San Francisco. When I wasn't working on projects for them they were happy to let me to use their software and tools to design the circuit boards and program the bot.

The chassis of WeddingBot was pretty simple, two boxes from Daiso, some wooden columns, and a motor kit with wheels. A large computer fan with plastic ducting was used to blow flowers out of the top. The bot was powered by RC car batteries (purchased at a hobby shop) and had a circuit board I designed for translating wireless commands from the controller (sent via an xBee Pro) into motor/fan responses.

The controller was based on an old Microsoft Sidewinder joystick I've had since middle school. I took it apart and connected the button and stick position outputs to another circuit board to translate the joystick inputs into wireless commands the robot could understand.

Both the joystick and robot circuit boards had microcontrollers that I programmed in C.

Driving WeddingBot was pretty straightforward. The amount the stick was tilted forward or back determined the overall speed and the left/right position determined how much it would veer left or right at that speed. Holding the trigger button would turn on the fan so that flowers would launch out. The back button would switch left/right turn commands to make driving the robot towards you more intuitive (since your left and the robot's left are opposite in that situation). I added an extra red button that could be used to re-center the joystick if the default position somehow became skewed.