I have an iPad and an iPhone. Unfortunately I don't know what apps exist on Android for Flipping, but much of the general commentary and advice should hold no matter what mobile device you use.
By far the easiest way to go is set up a phone or tablet and record. This could be with the camera pointed at a white/chalkboard while you deliver a short lecture or pointed at a piece of paper recording your hand with a pen or pencil writing on paper. If you are standing at your board you will have to be sure to speak very loudly and work when there is no (or little) background noise. Most mobile devices can simply take the recorded video and then upload it directly to YouTube or Google Drive either directly or with the use of free apps. They will also have apps available to allow you to do some editing of the content as well.
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This has become my favorite way to create videos for my students. It is just so easy and requires no extra setup at all. You'll need some sort of app. I've used Explain Everything on my iPad and I would strongly recommend it. There is also an Android version of Explain Everything and while I've never tried it, if I had an Android tablet I'd buy it simply based on my experience on the iPad. It's not a free app and I say that's a good thing! It only costs $2.99 and I'd still buy it if it cost $29.99! Developers need to eat too and I want to make sure they keep making this awesome app even better in the future. You can see my complete set of iPad recommendations as well as Explain Everything tutorials in my iTunes U course "Flipping with an iPad"
Whatever program you use, you'll want to make sure you can download or save a copy of the actual video file. Some of the free apps will only stream your video from the cloud. If you can access the original video file you end up with a lot more options. Also you don't want to create a year's worth of material and then have the company that was hosting it go out of business and take your material with it. If this happened in the middle of the school year this would be even more tragic.
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