Category Archives: General

Does your device support Bluetooth LE? Here is how to find out.

See Part 0 for a brief introduction to this series and Bluetooth LE plus our past tutorial series on classic Bluetooth for communicating between Android devices, and between an Android device and an Arduino board with external Bluetooth transceiver.

Note – Bluetooth LE was introduced in the Bluetooth 4.0 specification. As of this writing, the latest version of the specification is 4.2. Bluetooth LE introduced capabilities to support very low power, battery operated devices that are designed to operate for weeks to months on a single battery or battery charge

Does Your Device Support Bluetooth LE?

To find out if your smart phone or tablet can work with Bluetooth LE: Go to the Google Play store and install the free app “BLE Checker” on your Android device. The app is simple – it tells you whether your device supports Bluetooth LE or not and that is all it does.

Devices that support Bluetooth LE will support BLE connections between compatible devices. However, this app does not tell you if your device supports a special BLE feature called “advertisements”. You can use Bluetooth LE without the “advertisements” feature but you will not be able to use all BLE features.

Continue reading Does your device support Bluetooth LE? Here is how to find out. web site read in 183 countries around the world!

Wow! I just checked the web server data and the server estimate the web site is now read in 183 countries!

Using the United Nation’s count of 241 countries and territories, that means residents of 58 countries and territories have not visited yet!

But that means people in up to 183 countries are learning how to program Android apps using MIT App Inventor!

Some computer joke in this

Saw this sign at a campground, identifying 4 separate roadway loops where people may camp.

For programmers, this sign is amusing. “A Loop”, and “BCD Loops”. BCD stands for binary coded decimal, which is a way of storing decimal numbers for financial calculations. I know, bad joke – but one of those things that makes us software developers have a good laugh 🙂


MIT Professor Seymour Papert, passed away 31 July 2016

MIT Professor Seymour Papert was a forward looking visionary who pioneered the adoption of computing concepts in children’s education, including the development of Logo, Mindstorms and turtle programming. His distant work back in the 1960s and 1970s lay the foundation for today’s use of MIT App Inventor in children’s education. His contributions to education and computing are greatly appreciated.

Much more about Paupert’s background may be read in the NY Times or in this essay by a colleague here.

Introducing my “Internet of Things” Blog

The “Internet of Things” refers to connecting all types of products and sensors to the Internet.

Sensors, microcontrollers and communications are so inexpensive they can be built in to many objects and devices.

For example, a light bulb (or light switch) can detect the presence or absence of people in a room – and automatically turn a light on or off. A light bulb that can detect people in a room could also become part of a security system by transmitting the room status to another device (security alarm) or to a smart phone app or to an Internet application running in “the cloud”.

In this way, a “dumb” device (light bulb) becomes enhanced to perform new functions and become more valuable than “just a light”.

The Internet of Things (or IoT) refers to adding sensors, controllers and communications to all sorts of “things”. Devices become connected to the Internet – and even our lightbulbs might end up with IP addresses!

I just launched a new web site – “Coldstreams Internet of Things” – that will focus on the Internet of Things, and the related subjects of robotics and automation.

Regarding robotics and automation, the same inexpensive technology that makes IoT possible is creating new opportunities for robotics and automation. We will see the development and adoption of new kinds of automation, far sooner than most people realize. These technologies are not in the distant future but are available now, particularly in business and industry.

To visit the web site, go here: Coldstreams Internet of Things

Follow on Facebook here:

While IoT is separate from App Inventor, there will be overlap. I am sure many of us are dreaming of MIT App Inventor apps that interface with external devices! I know I am!

Why the name Coldstreams? Long story but I’ve had that name and URL for a very long time. It was used in the past for a small business and then for a blog on technology and business. I have relaunched the web site to focus on Internet of Things. That said, about 2,000 original and now dated blog posts are still there – and on the Facebook page!

Sorry for the delays in getting more tutorials up!

I have been busy with other projects.

But I have a big list of ideas for more tutorials and App Inventor projects! As time becomes available (which should be soon!) I will be posting more items here.

I am also beginning to study the Internet of Things market and technologies. App Inventor may play a role in this exciting new technology where everything is potentially able to communicate with other objects and the Internet.

Ed usage

This web site is now receiving 25,000 unique visitors each month! I am very pleased that these tutorials are helpful to so many people all over the world!

Web site access is nearly the same every hour around the clock, implying a global readership (update: 145 countries!)

Operating System Used

  • 82% of the visitors use Windows
  • 7% use Linux
  • 4.4% use Mac OS X
  • 1% use iOS (iPhone/iPad)
  • A very tiny number have accessed the web site via Java Mobile, Blackberry and … the Nintendo Wii plus a few miscellaneous devices.


The web server output an average of about 800 kbytes per minute delivered to those viewing the web site. That is nearly 1 megabyte per minute.

Browser Used

  • Internet Explorer 42%
  • Chrome 32%
  • Firefox 12%
  • Opera 5%
  • Safari 2%
  • Android browser on smart phone 1/2%


I do not yet have a count of countries. I am working on that.

UPDATE: 145 countries!

How Do People Find

  • 67% come directly to the web site by typing the address or using a bookmark
  • About 1% come from a link on another web site
  • About 32% come from an online search, and almost all of those come from Google searches.

The most common search is for information about App Inventor (duh!), followed by information about Bluetooth! High in the search list are also searches for information on Android or App Inventor and Arduino and searches related to App Inventor sensors (such as orientation sensor) and TinyDB.

How Do We Know This?

When you visit any web site, your browser sends information about the operating system used, screen size, browser used, and so on, to the web site so the server can optionally deliver a web page customized to your configuration. When you search for something online, the search service (such as Google) passes the search text to the web server so web developers can optimize their content or learn what content is most desired by users.

The web server does not know who you are.

Anti-spam feature added to this web site blog

Spammers are starting to hit this web site pretty hard – registering fake accounts, attempting to post comment spam and more. I have just paid for a software plug-in that appears to prevent the fake accounts and comment spam.

I hope this does not impact the ability of readers to post their questions and comments and I will be checking on this over the next week to adjust settings, if needed. So far today, the plugin has successfully blocked 100% of the spammers.

With volume 4 done and rain in the forecast soon, I should have a moment to resume work on new tutorials and examples! is back online!

On 28 March 2016 you may have received a “Bandwidth Limit Exceeded” error message when trying to access

This occurred because interest in tutorials on coding in MIT App Inventor is high! And the web server had exceeded the total bandwidth permitted for the month of March. I should have paid attention to the bandwidth logs and noticed sooner that I was closing in the bandwidth limit.

As soon as I learned about the problem, my Internet host (Tierpoint/ responded very quickly to increase my bandwidth to six times more than it was previously. Hopefully this will hold us for a few months! It costs me a bit more but I want to ensure you have access to the current content and more to come!


P.S. Tierpoint/ has been a great hosting provider for this and other web sites I have run for years, with excellent customer service. I am glad to put in a plug for them!