Prepare Your Device
Storage Space?
Video files are large, compared to other digital data. So you need to be sure you have the room on your phone
Free Up Space On Your Android Device
Disable Notifications
When you are recording a video, you probably want to disable notifications. Text messages, updates from apps, and even phone calls can be a nuisance that adds noise and breaks your concentration while you are trying to film. Both iOS and Android have a Do Not Disturb feature that can help with this
Do Not Disturb (Notification Control) on iOS
Do Not Disturb (Notification Control) on Android
Camera Apps
iOS and Android phones both come with apps that take photos and record video. These will probably do what you want them to.
App Settings
You may need to shift from static photography to video. This is usually a pretty obvious option. (In the Android Example image, "Camera" will take still images, while "Video" records motion picture).
You need to choose a resolution. 1080p might be a good all-around resolution, but if you want or need higher quality (as in the Android Example image), and your device can record it, you can choose that instead. However, that will mean a larger video file.
If you really want higher performance in your videos, and think it worth your while, you can experiment with third-party camera apps available in your app store. They can often do things the native apps in Android or iOS cannot, such as offer more focus modes, or turn-off auto-focus so you can force the camera to maintain focus.
For instance, a popular and powerful app for Android is Open Camera. But if you are satisfied with the native app, it's probably easiest to stick with that.
Top-Down Video Recording
You can use your mobile device to record top-down video. This can be handy if you wish to use handwriting, instruments, financial calculators, or even just discuss a photo or image in a book as a mini-lecture. This may be an essential part of your lecture or demonstration teaching, or it may simply be a creative way to teach with video, instead of using screencasting or filming yourself.
Gooseneck Arms
Obviously, you'll need a way to support your mobile device (or camera) above your workspace. You may have audio-video equipment such as scissor arms for supporting microphones (you can get adapters to go between screw-thread sizes) but if not, gooseneck arms, together with mobile phone clips, can be low-cost options:
Here's a small-budget example that's strong enough to support a webcam or mobile phone.
Here's a more expensive option that can support mirrorless digital cameras, or possibly lightweight DSLR cameras as well.
Simultaneous or Separate Audio?
With top-down recording (as with screencasting) you have the option of recording your voice while you are recording the video, or recording your voice narrative separately, and attaching it to the video later using editing software.
Recording simultaneously is obviously faster, although depending on what you are doing, it could be trickier to get a clean, clear narrative. It's probably best to try simultaneous recording first, and if you find that it's difficult, record the video and narrative separately.