Difference between revisions of "Project Straylight"

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== Goal ==
== Basics ==
To build a $500 educational project to display and demo at the upcoming EDExpo (late February 2015)
We have a $500 Budget (funded!) to build an educational project to display and demo at the upcoming EDExpo (late February)


== Plan ==
== Plan ==
Build a portable, RaspberryPi based Lightboard for recording lessons/lectures/demos. A lightboard allows the instructor to write on a whiteboard in front of them while facing the camera. See: [https://sites.google.com/site/northwesternlightboard/ Northwestern Lightboard] for examples
Build a portable, RaspberryPi based Lightboard for recording lessons/lectures/demos. A lightboard allows the instructor to write on a whiteboard in front of them while facing the camera. See: [https://sites.google.com/site/northwesternlightboard/ Northwestern Lightboard] for examples
Demo videos:
[Youtube|https://www.youtube.com/watch?v=ZsAPPUVK-DY&list=PLqATPiC_Bcl-t8vrzZlnGi3HTurs9Yuf3]


== Status ==
== Status ==
The basic lightboard is assembled and working.
Randy has RasPis, a Wolfson Audio board (use or not for audio input?), RasPi camera, a ton of 25mm black anodized aluminum extrusion.
 
The RaspberryPi and camera is set up to automatically boot into camera preview mode with the image flipped horizontally.
 
== Project Description ==
A lightboard allows an instructor to record educational material to be presented online (either streaming live or after additional post processing and editing) in a natural manner. Notes and diagrams are easily written directly on the transparent board between the presenter and the camera, without the need for the presenter to turn their back to the virtual students (as in a traditional classroom setting with a whiteboard behind the presenter).
 
The presenter writes and draws naturally in their own handwriting as the camera handles flipping the image horizontally before the student views it. The real-time preview screen aids in the presentation. It is like watching oneself in a mirror instead of a traditional studio monitor that is inverted left to right. Additionally the text drawn on the lightboard is seen immediately in the same orientation as it will be viewed by the students.
 
The edge lighting of the transparent dry erase board creates an effect of bright, clear letters easily viewable that appear in midair in front of the presenter and the black background. The dark solid background also allows for easy insertion of images using post production video editing software, or through a hardware video mixing board.


Project Straylight is built using commonly available aluminum extrusion sections holding a sheet of ¼” acrylic, RGB LEDs for edge lighting, and a RaspberryPi single board Linux based PC with an inexpensive HD camera. The backdrop is heavy black canvas fabric on a PVC frame. In a studio environment, the back wall could be painted a matte black finish instead.  
Steven is in charge of the LED edge lighting. We'll need to do some back and side lighting of the subject too.


DMM is looking at an open stack for video switching


== Budget ==
We'll need lots of fab help, and likely some programming and integration help on the RasPi side
=== RaspberryPi Recording ===
* RaspberryPi B: $35
* RaspberryPi Camera: $30
* Monitor with HDMI input: $100
* Powered USB Hub: $10
* USB sound card for recording: $10
* Microphone: $15
* HDMI and misc cables: $20
* RaspberryPi Mount: $0 (3D printed)
* VESA Mount to monitor: $0 (Laser cut from scrap acrylic)
* Software: $0 (all open source)


=== Lightboard ===
== Needs ==
* 3x6" .220" thick Acrylic: $100
=== the glass/acrylic ===
* 25mm extruded aluminum frame: $80
We can get 3x6' 6mm/.25" acrylic for $110 locally. Need to price a piece of similar sized tempered glass (with at least one top and one side edge polished so it can be edge lit) . Not married to the size, but approximately this ratio and probably not smaller than 3x5' or larger than 4x8'. It would be great to find a readily available piece, either something kept stocked or a frameless shower door that wouldn't break the budget. 6mm or .220. If larger than 6mm we'll have to mill out the slot in the aluminum (up to maybe 10 or 11 mm) to fit it. More work and heavier.
* LED lighting strip and power supply: $25
* Neon EXPO dry erase markers: $15
* Black canvas for backdrop (2.75 yards): $10
* PVC for backdrop stand: $15 (estimate as this was scrap)
* Baskets for markers: $5
* Misc screws and brackets: $25


'''Total: $495'''
Pros/Cons
Acrylic will be lighter (and maybe cheaper), but prone to scratching and harder to clean. Risk that some markers might have chemicals that can etch the surface. Glass is heavier, some greater risk of breaking in transport, but won't flex when being written on or scratch.


== Todo/Version 2 ==
=== backdrop and frame ===
=== Software ===
Some sort of black fabric that can be hung behind the subject with low reflection
* Video mixer to be able to overlay images into the background in real time
A frame of some sort to set this up on. Height and width TBD based upon the glass size
* Experiment with the RaspberryPi cameras settings for white balance, image stabilization, etc for optimal recording
* Script that automatically starts and stops recording of video and audio on a trigger
* Script to mix the audio and video into a single file for easier post-production
* Auto-mounting of a USB thumb drive at boot time and set this as the default location for recordings, or post-mixing drops to eliminate users from needed access to the RaspberryPi


=== Hardware ===
=== HDMI or composite monitor or TV ===
* Give the presenter a remote control to start and stop recording from behind the board. Keyboard or mouse would be fine.
Something the subject can see themselves on. Needs HDMI or composite input so it can be driven from the RasPi
* Redesign the floor mounts of the board to be sturdier and to allow for a heavier board
Something VESA mountable a big plus
* Use tempered glass instead of acrylic for better long term durability (current budget wouldn't allow for this at approximately twice the cost, plus twice the weight)
HDMI to DVI/VGA adapter might work too with some existing surplus screens we have
* Edge light with solid white LED strip instead of RGB strip (RGD was available so was used although not necessary)
* Add a second RaspberryPi/monitor/45degree piece of acrylic in front of the camera for a teleprompter
* On-air light: Add a red LED to the VESA mount, hooked into a GPIO on the RaspberryPi, that can be turned on and off via script. This will edge light the mount with a red glow when the Pi is recording.
* Add WiFi and set up Network Time Protocol (NTP) or add a real time clock (RTC) to the Pi so the time stamping of files is accurate.
* If Lightboard is set up in a semi-permanent location (The podcast studio?) set up better ambient lighting for optimal recording

Revision as of 19:35, 28 January 2015

Basics

We have a $500 Budget (funded!) to build an educational project to display and demo at the upcoming EDExpo (late February)

Plan

Build a portable, RaspberryPi based Lightboard for recording lessons/lectures/demos. A lightboard allows the instructor to write on a whiteboard in front of them while facing the camera. See: Northwestern Lightboard for examples

Status

Randy has RasPis, a Wolfson Audio board (use or not for audio input?), RasPi camera, a ton of 25mm black anodized aluminum extrusion.

Steven is in charge of the LED edge lighting. We'll need to do some back and side lighting of the subject too.

DMM is looking at an open stack for video switching

We'll need lots of fab help, and likely some programming and integration help on the RasPi side

Needs

the glass/acrylic

We can get 3x6' 6mm/.25" acrylic for $110 locally. Need to price a piece of similar sized tempered glass (with at least one top and one side edge polished so it can be edge lit) . Not married to the size, but approximately this ratio and probably not smaller than 3x5' or larger than 4x8'. It would be great to find a readily available piece, either something kept stocked or a frameless shower door that wouldn't break the budget. 6mm or .220. If larger than 6mm we'll have to mill out the slot in the aluminum (up to maybe 10 or 11 mm) to fit it. More work and heavier.

Pros/Cons Acrylic will be lighter (and maybe cheaper), but prone to scratching and harder to clean. Risk that some markers might have chemicals that can etch the surface. Glass is heavier, some greater risk of breaking in transport, but won't flex when being written on or scratch.

backdrop and frame

Some sort of black fabric that can be hung behind the subject with low reflection A frame of some sort to set this up on. Height and width TBD based upon the glass size

HDMI or composite monitor or TV

Something the subject can see themselves on. Needs HDMI or composite input so it can be driven from the RasPi Something VESA mountable a big plus HDMI to DVI/VGA adapter might work too with some existing surplus screens we have

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