55c083f9 cc93 4de5 ba4a f87775b18a8e


Lego Valentine

by JackANDJude

Published on February 11, 2015

Surprise your loved one with an electronic Valentine.  :)   When your special someone comes home and turns on the light, the heart will spin and the buzzer will sound at different rates.  As the heart casts its shadow over the light sensor, the DC motor will spin slower and the buzzer will change pitch.

This project uses red legos and 3 brick adapters.  Redesign yours with cardboard if you don't have legos.

Here is the video link: http://youtu.be/W5LgbGme758

How To Make It


Assemble circuit Assemble this circuit on brick adapters: power + wire + light sensor (light mode)+ wire + DC motor + buzzer
A996b94a 5a7a 4d9e 90db f3ecc5d5db52


Build a heart Build a lego heart as shown in the pictures, or substitute your own paper/cardboard heart.
412cb678 b57a 4e39 a268 60501e93f3b5


Build a tower with shelves Build a lego tower with 2x6 bricks or a combination of 2x4 and 2x2 bricks. Make shelves with 4x6 base plates. This is where your brick adapters will rest. I made 3 shelves: 1) The bottom shelf holds an upside down brick adapter underneath it for the power + wire. 2) The middle shelf holds an additional 4x6 base plate at a 90 degree angle. This is where I situated the wire + light sensor + wire on a brick adapter. 3) The motor sits on the top/center of the tower on a brick adapter with a buzzer next to it.
6813b402 09e0 4a34 ad26 3a1bdb9c7878


Test & adjust Rearrange the shelves and adjust the light sensitivity so that the heart can cast a shadow on the light sensor only some of the time. That way the motor will go slower sometimes, and the buzzer will go on and off. It takes patience to make this electronic valentine turn on when someone turns on the light, but it is possible.
C8fc1f2a c245 4247 9b0d b064948037ea

Related Projects

Mini, Rotating Personal Fan

Small enough to carry in a bag to work, school, the library, or place on a car seat, etc.

Turn Down For what bag! #HackPack

This bag is the only turn down for what bag in the world!Besides of having a sound system, it can sensor the enviroment and measur...

Jack the Elf cookie stealer Detector. #HACKYOURHOLIDAY

The kids wanted to set a trap for the elf but I told them he was too quick... So I set up a motion detector to send me a text when...