Lightpainting LED Wand
About This Project
This device is a tool for long exposure photography. It is a collapsible strip of LEDs that the user moves horizontally across the plane of view of a camera taking a long exposure image. While this happens, each RGB LED pixel of the strip is individually addressed. The final result is a user selected custom image.
I took on this project since I have always been fascinated with light painting and wanted to develop a way of painting custom images with it.
Interactive Model
Exploded View
How It Works
The device is controlled remotely by a Raspberry Pi. The user uploads any custom image of choice over WIFI which is then processed using Python with PIL. The user runs the program via a touch screen connected to the Pi and takes a long exposure image with a camera simultaneously. As the camera takes the image, the user moves the strip of LEDs horizontally in front of the camera's plane of view. Each LED is individually addressed during this time with it's respective RGB value at the correct timing. Since the camera is taking a long exposure image, all light that is exposed to the camera's sensor will be captured, this is what makes light painting possible.
Design Requirements
Must be able to collapse and safely fit into a backpack
Portable, battery pack supports Raspberry Pi + 144 RGB LED cells
LEDs must not be under tension when collapsed to prevent damage
Notable Engineering Decisions
Designed a slot following hinge-mechanism that prevents over rotation for the carrying handle
Thoughtfully designed hinge mechanisms to de-tension the LED strip before folding to prevent damage.
Designed slot follower mechanism to prevent the handle from over-rotating during use.
Developed python script the address each LED individually with the correct RGB value and timing.
How It Was Made
The device was fabricated using custom designed SLS 3D printed components and 6mm laser cut clear acrylic.Â
The electrical work involved sourcing appropriate power sources for the Raspberry Pi and LED strip and soldering necessary connections.
For reference from ideation to final product, this project took 8 days including fabrication time and waiting for parts.
Results
Folding mechanism reduces the length of the wand from 1000 mm to 370 mm, easily fits in backpack.
Python script re-sizes images and converts the image to readable data for the Raspberry Pi to address LEDs with appropriate coloring at the respective timing.
Can wirelessly upload images over Wi-Fi to Raspberry Pi
Capable of producing multi-colored high-resolution light-painted images.
Battery packs sized by calculations allow for 2.5 hours of battery life with constant usage.
