The Very Spring and Root

An engineer's adventures in education (and other musings).

This content shows Simple View

video

Use Your Phone as a Streaming Document Camera

As a science teacher in an increasingly technology-driven world, I have found document cameras to be very useful for a number of purposes. A connection to the SMART Board or projector allows students an enhanced or alternative view of any class demonstrations, and I can also ask students to explain their written or solved work for the class with everyone following along on the screen.

Document cameras ain’t cheap though. The official SMART Document Camera runs about $800 (!), and even a generic webcam can run $40-50 or more depending on what you are looking for. For the budget-conscious (or budget-constrained) educator, these options can be beyond reach.

I was looking for a cheaper alternative and thought, wait a minute. I’ve got a camera right here on my Android phone already. Why not find a way to use that?

Here are the results from trying out two different apps.

Phone Stats

I have a smartphone, but its a pretty generic one. Go back to that bit about budget-constrained. Right.

LG Optimus V (Virgin Mobile), with Android 2.2 and a 3.2 MP camera.

IP Webcam

The Android app IP Webcam allows you to turn your phone into a little video stream server. You can adjust various settings (video resolution and quality, orientation, etc) and then stream to a local IP address. The stream URL can then be viewed via a media client like VLC or Quicktime, or directly through your browser’s native video player.

You can also have it fade the screen to blank to save battery (it doesn’t let you actually shut off the screen, since that seems to be linked to ramping down the processor as well).

The partial screen capture (scaled to 60%) below shows the feed in Firefox with the phone held about a foot away from the document under a normal table lamp in otherwise dim lighting conditions.

ipwebcam_shot

Here is another screen shot, also holding the phone about a foot away, that shows resolution of handwritten text and diagrams for demonstrating problems.

ipwebcam_writing

Five minutes of WiFi broadcast at 640×480 (3MP), full quality, and phone screen on fade-mode resulted in a battery drain of only 2%, which is pretty good. If the display were left on, I’m sure this would be much higher. I also have a very weak processor and no autofocus, both of which would take more power if your phone has them. However, I see no reason why you couldn’t just plug in your phone while streaming if you needed it.

As you can see from the browser control interface below, the app supports many ways to access the stream (including Skype integration), and also allows screen-capture photos and audio streaming as well (I did not test the bitrate).

ipwebcam_control

I was not able to get the stream to work over 3G, since the IP address that the cell tower assigns to my phone seems to be LAN only. It would be an interesting experiment to see if another Virgin Mobile customer standing next to me (and hence presumably connected to the same tower) would be able to see my stream on his/her phone!

DroidCam

The DroidCam app works through either WiFi or USB, and hence requires a client install on the viewing laptop. The pro version claims to also add 3G and bluetooth connectivity, as well as remote control for flash, zoom, autofocus, etc.

The app performs poorly compared to IP Webcam. The video quality is noticeably lower for the same resolution, and the phone experiences a higher battery load (3.5% in five minutes, same conditions). Also, the option to display the stream through the browser via an http connection is disabled unless you buy the pro version, so you must use their client software to view the stream.

The advantage over IP Webcam presumably is that you can use USB mode to stream directly to a client computer even when you don’t have WiFi available. However, I was not able to get the USB mode to work properly on my Windows 7 netbook with minor fiddling. I would assume that if one could get the USB mode working, battery drain would be significantly less, since the phone should be able to draw on the USB power bus while connected.

Conclusions

Of the two apps tried above, I would go with IP Webcam for sure. I tried the app on WiFi mode while connected to the BPS network and it worked fine (the app uses the standard http web port 8080, which means that its highly unlikely anyone will block the port). There seems to be no need to try very hard to get the USB on DroidCam to work, especially considering that the quality is lower.

At only 3MP, fine detail is going to be lost, but for visual enhancement it seems like this should work fine! Also, if you have a higher resolution phone camera than me, obviously your phone will deliver a higher resolution image.

Bonus: the web streaming means that any student with the right IP address (which you can give them) on the local net can actually get the stream directly on their smartphones or laptops anywhere in the school. I don’t think even the $800 SMART Document Camera will do that, and this app is FREE!



We Need More Science Teachers

One more video posted from BTR, this one an interview on science teaching in particular and why we need more science teachers.



Why Teach? – BTR Promo Videos

My teaching residency program, Boston Teacher Residency, has released a series of video interviews about the program and about urban teaching. Including my colleagues Randyl and Malcolm, as well as yours truly! Check them out below:

Randyl Wilkerson giving an introduction to BTR:

Malcolm Jamal King on being a male teacher of color and why he chose to teach:

And here’s me talking about why I chose to change careers from engineering to teaching:



Lesson Plan: Conservation of Energy using a Music Video

Lesson 2.2: Exploring Conservation of Energy

Unit: Work and Energy, Component 2 – Conservation of Energy
Date: January 10th, 2013
Day/Block: Day 1 –  A/E/F
Time Available: A 58min / E 48min / F 65min

Objective:
You will be able to design and analyze a Rube Goldberg Machine using the Law of Conservation of Energy.

Criteria for Success:
Can I design my own machine that transfers mechanical energy between objects through work?

Can I use the Law of Conservation of Energy to explain how my design transfers energy?

Assessment:
Handout with machine design and analysis questions.

Agenda:

[10 min] DoNow:

The complicated chain of events in the music video is called a “Rube Goldberg Machine”. These machines use many transfers of energy between a whole lot of objects in order to do a very simple task.

Invent your own small (2 objects) Rube Goldberg machine. How would you use one object to make another object do something else? Where is there work and energy? How does one object transfer energy to another?

Example:

[10 min] Discussion: Music Video

Show OK Go’s music video for “This Too Shall Pass”: (4 min)

Note: Watching the video was assigned as homework the previous night, along with the following guided questions: Where do you see work? Where do you see energy being transferred from one form to another? Write down at least 1 example (note the video time), and make sure to explain what object is doing work on what other object, what kind of energy is being transferred, and how you know.

Talk to a partner next to you and share 1 example of work and energy being transferred from one object to another. I will ask several students to share an observation that their partner noticed, and explain to me what object is having work done on it and what kinds of energy are involved.

Possible questions to ask:
What did you see? Be specific, tell me what happened to the object that makes you think there was work done. What kinds of energy do you think that the object has?  How do you know that the object has that kind of energy?

Record student observations on the whiteboard.

[15 min] In-Depth Analysis: Tire

Show video clip of the tire section twice (7 second clip starting at 1:03). Ask students to write down exactly what they see happening to the tire. Have students share their observations, and assemble a record of the tire’s journey on the board to refer to later.  (Make sure that the bucket hitting the tire is included.)  Hand out the worksheet for scaffolded analysis of the tire scenario.

Refer to your handout. Take 30 seconds to answer the first question by yourself. Ask one student to share what they wrote with the class.
1. At the beginning of the scenario, does the tire already have mechanical energy? If so, what form(s) is it in, and how do you know?

Take two minutes to answer questions 2 and 3 with a partner.  Ask one or two pairs to share, depending on time.
2. During the scenario, is work done on the tire by any other object?  Is this work positive or negative, and how do you know?
3. What happens to the tire’s total mechanical energy when the work is done to it?

Take four minutes to answer questions 4 and 5 with a partner. Ask one or two pairs to share, depending on time.
4. Describe what happens to the tire’s GPE, KE, and total ME as it goes through the scenario.
5.  What happens to the tire’s mechanical energy at the end of the scenario?

[15 min] Creative Activity: Design and Analyze

Turn over your handout. Now you have a chance to design your own Rube Goldberg machine! Draw your machine in the space provided, and use the Tire Analysis as a guide to answer the analysis questions below. The questions are due tomorrow for stamps. If you don’t finish in class, please complete the analysis questions as homework.

6. Draw your own piece of this Rube Goldberg Machine that uses 1 object. You must include at least 1 transfer of energy from one object to another.

7. What is your main object in this scenario? :

8. Describe what happens to your object’s GPE, KE, and total ME as it goes through the scenario beginning to end..

9. Where is work done on your object or by your object? How does this work change your object’s total mechanical energy?

10. Explain how your machine obeys the Law of Conservation of Energy, MEi + W = MEf.



BTR at Americorps Opening Day 2012

“Boston Teacher Residency’s 10th Cohort was well represented at the 2012 Americorps Massachusetts Opening Day in Boston. Juliet Buesing and Randyl Wilkerson sang “Lift Every Voice” (the Black National Anthem) and Malcolm Jamal King presented the introduction to what BTR does. Cohort X followed the ceremonies with an afternoon of service at Cradles to Crayons.”

 




top