Enabling Technologies

Enabling Technologies,
Medical School Administration
Project: Go-Cart

Go-Cart prototype is a mobile video conferencing unit featuring digital video quality. It can be easily moved from one office or hospital room to another.

To move the Go-Cart, simply unplug the power and ethernet cables and you're ready to roll! The Go-Cart is built from readily available, inexpensive components and supports the following Video Conferencing services:

DVTS - (Digital Video Transport System) DV quality video, requires a network connection capable of 30 mbps
ConferenceXP - requires a network connection capable of 10 mbps
Adobe Connect (formerly called "Breeze") - requires a network connection capable of 6 mbps
Access Grid - requires a multicast network connection capable of 20 mbps

Learn more about Go-Cart:

Design Criteria
Hardware Components
Software Components
howto: do a DVTS video conference
howto: join a ConferenceXP collaboration session (coming attraction)
howto: build your own Go-Cart (coming attraction)

If you're wth the UMMS, you can make arrangements to use the prototype Go-Cart by contacting Karen Kost (kkost @ umich.edu), Office of Enabling Technologies, Medical School Administration, University of Michigan.

If you're not with UMMS but are interested in borrowing the Go-Cart, pleas contact Bob Riddle (bdr @ umich.edu), Office of Enabling Technologies, Medical School Administration, University of Michigan.

Design Criteria

The goal was to create a mobile, DV capable video collaboration tool from affordable, available components that is usable, reliable, and compelling.

High quality video was desired so the "better than H.323" video choices were HD and DV. Low latency transmission was desired, thus uncompressed DV video was chosen and a Sony HandyCam is used as the video capture device.

Good audio without "echo" was desired. While there are many devices that deal with echo cancellation, a ClearOne Chat 50 was chosen because it is affordable, extendable, provides good quality audio and compares favorably to other devices in the same price range.

Since DVTS capability exists in the hardware (Comet PMC) and software, we chose the solution that required the least amount of hardware with the most common user interface. The DVTS freeware is being run on a Windows XP machine.

A 22” computer monitor is used to capitalize on the ability to present an HD (high definition) perspective (16x9).

Hardware Components

A Sony HandyCam DCR HC1000 NTSC unit is used for video capture on the Go-Cart. Any "HandyCam" that support IEEE 1394 (firewire) and an external microphone may be used.

A Chat 50 echo cancellation device is used as both microphone and speaker. A microphone cable is plugged into the HandyCam (white plug seen in the HandyCam picture) from the back of the Chat 50 and a speaker cable is plugged into the speaker port on the computer from the back of the Chat 50.

Wireless keyboard and can easily be removed from the cart and used anywhere in the vicinity.

The computer hosting the Windows XP version of the DVTS software is a Mac-mini. (That's right, a Macintosh computer) This computer was chosen because of the price, the small physical footprint, and because is it a very quiet machine.

We also installed an Uninterruptible Power Supply (UPS) so the Go-Cart is immune to local power failures during a video conference. The current estimate is that the UPS will power the Go-Cart equipment for up to 60 minutes.

Software Components

Windows XP with Service Pack2
DVTS version 0-2 for Windows
ConferenceXP client 4.0
Access Grid Toolkit 3.0

howto: do a DVTS video conference

Let's assume you're logged into the Windows machine. You should see something like this on the monitor:

After you make sure the camera is on and working, Select the icon that is labelled "DVTS Video Conference" double click it to launch the DVTS program.

You should now see a window that looks like this:

The "DV Send" section of the window contains the parameters that control the sending of video and audio. The lower half of the window, "DV Receive" contains the parameters that define the stream that will be received.

Sending your video across the network:

1. select the "DV" device from the pull down menu. Your like selection option will be "Sony DV Device"
2. fill in the "Destination" text box with the IP address of where you wish to send you audio & video
       a) if this is another machine, then enter the IP address of that machine (the unicast address)
       b) if this is to be seen by multiple machines, then enter the multicast address and then
           make sure to fill in the "Multicast TTL" with a number, 64 is suggested.
3. if you want to see the video that is being sent, then click on the "Preview Monitor"
4. click on the "Start Send" button to begin sending the video to the specified destination.

If you chose the "Preview Monitor", another window will open and you will see the video being captured & sent from the camera. If there is no video in that window, make sure your camera is turned on and plugged into the computer.

Receiving video from the network:

If you need to receive a unicast stream from another DVTS node, then click on the "Start Receive" button.

If you need to receive a DVTS multicast stream, then fill in the text box "Multicast Group" with the multicast address as shown below. Then click on the "Join" button and you are done.

Another window should open, displaying the video being sent from the specified endpoint. If no video window opens, it means you are not receiving the specified video stream.