All posts by edwardm

General

Subscribe to AppInventor.Pevest.com by email

I have added a new “Subscribe by email” feature to provide another way to be alerted to new posts on this web site.

Look for “SUBSCRIBE TO POSTS BY EMAIL” in the right column of this page, then enter your name and email address and click on Subscribe.

Check your email for a confirmation message and click on the link in the email to confirm your subscription. If you do not receive a confirmation email within a few minutes, check your Spam mail folder – and then check to make sure you entered your email address correctly!

I have only tested this feature with my own email address but hopefully it will work well for anyone who wishes to receive post alerts via email!

Facebook is a simple way to be alerted to updates, but you may also wish to use Twitter, our RSS newsfeed, or the new email subscription – or all of them! My intent is to make it simple for you to receive new posts in what ever way works best for you.

App Inventor News

App Inventor Classic (version 1) to Shut Down on July 15 

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Most users are already using AI 2 and are unaffected by this change. But if you are still using AI Classic (version 1), then this message is very important – please click through the link to read the full story!

May 24, 2015 — MIT App Inventor Classic will shut down on July 15, 2015. After July 15, 2015, you will not be able to access or edit your existing AI Classic projects. It will be impossible to create new AI Classic projects.This shutdown applies only to AI Classic (AI1). App Inventor 2 (AI2) will not be affected.

MIT will not automatically convert your AI1 projects to AI2 projects. But MIT will provide a conversion tool that will help you convert the AI projects that are important to you into AI2 projects. We expect to release this converter in about 2 weeks (i.e., around June 8).

Source: App Inventor Classic to Shut Down on July 15 | Explore MIT App Inventor

How do you know which version you are using?
Login to App Inventor and create or open a project. If the URL address in your browser begins with
http://ai2.appinventor.mit.edu/

then you are using Version 2.

Components, Programming Method, Tips

Can you make a video player in App Inventor? Not really, unfortunately.

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A question from a reader: Can we make a video player in App Inventor?

The short answer is, unfortunately, not really.

In the App Inventor Designer, in the Palette’s Media section, you can drag a Video Player into the viewer. But this Video Player only plays video files (WMV, MP4) that are stored inside your app (not on the web) and these files are limited to just 1 megabyte in size. Therefore, the Video Player feature in App Inventor is so limited as to not be very useful for most applications.

 

Tips

Android battery life – and how to extend your battery power

When I had a Nexus 4 running Android 4.3 and earlier, I used an app called Juice Defender to extend the time between battery charging. I often went 2 days without recharging the battery!

But Juice Defender has not been updated since 2012 and due to Android changes, Juice Defender no longer works well.

Then, Android 5 resulted in worse battery life for many of us! My phone was discharging half the battery in 8 hours, even when not being used.

The only way to extend battery power is to reduce power demand. That means turning off hardware features that may not need to be used all the time (WiFi, Bluetooth, GPS location), dimming the screen or turning it off and so on. Another way to is reduce the frequency that apps wake up to “sync” or go online.

Good “Battery Saver” apps work by intelligently switching features off and reducing their frequency of use. Some battery saver apps are good and some are awful; in fact, some have displayed false battery status to pretend they are saving power! I have tried numerous Battery Savers but found only one that works effectively on the Nexus 5: Avast Battery Manager (see link below).

With that in mind, here are ideas that may help your device reduce its power demand and extend is battery life between charges:

  • Install Avast Battery Manager from Google Play. This works well for me using its “Automatic mode” settings. The app also provides information about which apps are consuming power on your phone. You may choose to stop, disable or uninstall apps that consume excess power.
  • Google Chrome and GMail apps are power hogs relative to other apps. It seems that if you visit a page, like a financial page, that periodically “auto refreshes” (e.g. for stock market data), this auto refresh may continue to occur periodically when you are not using the phone (this is my hypothesis – its not yet verified.) Avoid leaving Chrome on such pages, if you can. In GMail, go to the GMail menu (the one where you can select Inbox, Sent, Outbox, etc), scroll all the way to the bottom and choose Settings. For your GMail account, uncheck Sync GMail – and then manually resync GMail by swiping down from the top when you are using GMail. For POP3/IMAP email accounts (if any), set the sync time to 60 minutes (the longest option available) – or go to Settings | Accounts, select the email account, and turn off sync completely.
  • Many apps start up when your device is powered up and drain a small amount of power running in the background. Even if you never use the apps. Uninstall apps that you no longer use or you do not need.
  • Use Wi-Fi, if available, instead of cellular data. Generally, good Wi-Fi data links are much faster than cellular data, which means data can be uploaded or downloaded in less time. That means the transmitter (which uses more power) is active for less time, helping to reduce power. Further, due to some issues in how the cellular data protocol works, the cellular transmitter remains in an elevated power state for several seconds after being active for a data transmission. Related: While out and about and using only cellular data, turn off WiFi. You may also consider disabling Bluetooth and Location services.
  • If battery life seems to be getting worse, go to Settings | Storage, and scroll down to Cached data. Select “Cached data” and then follow the pop up menu to clear the cached memory. This is not something you do every day – but when the battery has gotten bad, taking this step every once in a while has significantly improved the battery power.
  • If you are using Avast, you can likely skip this step: Go to Settings | Battery and click on the 3 vertical buttons at upper right. Then click on Battery Saver and set this to “On”. Normally, Android’s own battery saver only activates when the battery is very low, but you can activate it manually. This built in Battery Saver reduces app data synchronization with the network, disables location services and does a few other things to reduce power. The Battery Saver is automatically turned off and remains off, once you plug in to a charger.
  • Aggressive: Set your device to Airplane mode. This turns off all built in radios and suspends background apps from doing data communications. Again, if using Avast, you are already getting good power management and this step adds only a little to the battery life. And while its activated, you cannot receive voice or text messages either!

Hopefully these suggestions are helpful to you!

Arduino, General

New Arduino Zero controller board

Atmel introduced the new Arduino Zero controller board, which includes new support for Bluetooth, Wi-Fi and sensors, apparently (I do not yet have details). A couple of weeks ago, I showed how to use App Inventor and Bluetooth to communicate with an Arduino board.

Here is a video clip about the new Zero controller board. I think App Inventor will also play an important role in the “Maker” / do-it-yourself community in terms of linking smart phones to external hardware devices, like this controller.

I am back from Maker Faire and will start catching up over the next few days. I was mostly offline while down there.