Updating BlueZ on Raspberry Pi (5.43 to 5.48)

This post shows how to update BlueZ from 5.43 (the default version comes with Raspbian Stretch November 2017 version) to 5.48 (the latest as of 2/14/2018) on Raspberry Pi.
According to the release notes [1], many issues (especially GATT related issues) have been fixed and also, Advertising Manager API, which was previously marked as experimental, is now stable in 5.48.

Here is the list of contents of this post.

– Assumptions
– Steps
1. Check Current BlueZ Version
2. Install Dependencies
3. Install Latest BlueZ
4. Verify Update
– Reference


In this post, I assume that you already have Raspberry Pi 3 or Raspberry Pi Zero W running Raspbian Stretch November 2017 version.


1. Check Current BlueZ Version
1-1. Before starting, let’s check the current BlueZ version.

In case you are using Raspbian Stretch (November 2017 version), the BlueZ version should be 5.43.


2. Install Dependencies
2-1. Update the package list.

2-1. Install the dependencies.


3. Install Latest BlueZ
3-1. Download the latest version of BlueZ source code.

3-2. Uncompress the downloaded file.

3-3. Configure.

3-4. Compile the source code.

3-5. Install.

3-6. Reboot Raspberry Pi 3.


4. Verify Update
4-1. Verify the BlueZ version by issuing the command below.

The result should be like this:


[1] BlueZ Release Notes
[2] Installing Bluez 5.44 onto Raspbian? – Raspberry Pi Stack Exchange



Deploying existing Django App to Heroku

Heroku’s free plan is great for experimenting/prototyping cloud applications. This post shows the steps to deploy existing Django project to Heroku cloud platform using Windows host. As an example, I’ll use this django app from GitHub and deploy it to Heroku.

Here is the list of contents of this post.

– Steps
1. Setup Python Environment on Windows
2. Install Heroku CLI and Git
3. Setup Local Environment (App & Django)
4. Verify Local Environment
5. Setup Heroku
6. Deploy your application to Heroku
7. Verify
– Summary
– Reference



Note: If you already have working Python/Django environment with pipenv on your Windows PC, skip Step 1, 3 and 4.

1. Setup Python Environment on Windows
1-1. Download Python installer from here. In this post, I use Windows x86-64 executable installer for Python 3.6.4 which is the latest at the moment.


1-2. Launch the installer.


1-3. Check on “Add Python 3.6 to PATH” option, then click on “Install Now”.


1-4. After Python is successfully installed, open “Command Prompt” (Press Win + x, then select “Command Prompt”.)


1-5. Install pipenv by running the following command:


2. Install Heroku CLI and Git
Since Heroku CLI (Command Line Interface) tool installer also installs Git which will be used in the next step, let’s install both here. Heroku CLI will be required later, in Step 5.

2-1. Download the installer from here and launch it.


2-2. When choosing components, make sure “Set Path to Heroku CLI” and “Git” is selected.


2-3. When setting up PATH environment for Git, make sure “Use Git from the Windows Command Prompt” is selected.


3. Setup Local Environment (App & Django)
Note: In this post, I use this simple-django-login as an example of existing Django app.

3-1. Re-launch “Command Prompt” to load the updated PATH environment variable for Git (and heroku CLI).


3-2. Clone an existing Django app.


3-3. Create a python virtual environment with pipenv.


3-4. Spawns a shell within the virtualenv.


3-5. Install “django”.


4. Verify Local Environment
Before applying any changes for heroku, let’s verify if the app works in the local environment.

4-1. Run the app by typing the following command:

The output should be like this:


4-2. Then access “” with a browser. If everything is fine, you should see “Django Simple Login” page.


5. Setup Heroku
5-1. Download PostgreSQL installer from here and install it.


5-2. Install “django-heroku”. This module configures Django app for deployment on Heroku. [4]


5-3. Add lines below at the bottom of “settings.py” in “login” app.


5-4. In “simple-django-login” folder, create a file named “Procfile.windows” with the content below.


5-5. Verify local heroku environment by typing below:

Then access “” with browser. You should see “Django Simple Login” page same as Step 4-2. Now, the app is working with heroku local environment.


6. Deploy your application to Heroku [5]
6-1. Install gunicorn.

Note: gunicorn is not required on Windows local environment but this step adds it’s package dependency to Pipfile, which will be used on heroku remote.


6-2. In “simple-django-login” folder, create a file named “Procfile” with the content below:


6-3. Create a Heroku account from here if you don’t have it already.


6-4. Login heroku account by using “Heroku Command Line Interface”.

You’ll be asked for your credentials.


6-5. Create heroku application. It automatically creates the git remote too.

The output should be like this:


6-6. Add files to git repo.


6-7. Commit it.


6-8. Upload to Heroku remote.


6-9. Migrate database.


7. Verify
7-1. Open the app by typing the command below:

The command automatically open “https://simple-django-login.herokuapp.com/”.




Now, your django app is up and running on Heroku cloud and you can access from anywhere.




[1] Migrating an existing Django project
[2] Heroku Django Starter Template
[3] How to Deploy Django Applications on Heroku
[4] Django-Heroku (Python Library)
[5] Deploy your application to Heroku



Changing Screen Resolution of Mac OS VirtualBox Guest

The default screen resolution for Mac OS X VirtualBox Guest is 1024×768.
Below shows how to change the screen resolution of Mac OS VirtualBox guest running on Windows 10.



1. Open “Command Prompt”. (press Win + x and select “Command Prompt”)

2. Navigate to VirtualBox folder in which “VBoxManage.exe” resides.

3. Set resolution by typing the command below.

The third parameter (i.e. “High Sierra”) should be your VM name.

4. Start the VM



[1] Fix VirtualBox macOS High Sierra Screen Resolution (1920×1080 – 4K – 5K)



Setting Path Environment Variable on Windows 10

The steps below shows how to set a file/folder path to the ‘Path’ System Environment variable on Windows 10.




1. Right-click on Windows start menu icon at the bottom-left corner of the desktop, then select “System”


2. Click on “Advanced system settings” on left side of the “System” window.

3. Click on “Environment Variables…” button on “System Properties” window.


4. Double-click on “Path” in “System variables”.

5. Click on “New” button, then type a path you want to add.



Enabling Webcam in VirtualBox Guest OS on Windows Host

This post shows steps to enable webcams in a VirtualBox guest OS on Windows host. OS/software and the version I used are below. I tested it with Microsoft Surface Pro 4 and Dell Precision 3510.

Host: Windows 10 running VirtualBox 5.2.6.
Guest: Ubuntu Linux 16.04.03 / Mac OS X High Sierra


Here is the steps.

1. Install ‘Oracle VM VirtualBox Extension Pack’
VirtualBox Extension Pack is required in order to use webcams in VirtualBox guest OS. [1]

1-1. From the VirtualBox Download page, download the extension pack which has the save version as your VirtualBox. In my case, my VirtualBox is v5.2.6 so I downloaded this:

1-2. Launch “Oracle VirtualBox Manager” and navigate to “File” -> “Preferences”.

1-3. In ‘Preferences’ window, select ‘Extensions’.

1-4. Press ‘Add new package’ icon.

1-5. Select the extension pack and install it.


2. Attaching webcam to guest OS
2-1. Launch the guest OS.

2-2. Launch “Command Prompt” on Windows (Press the Win + R keys, then, type ‘cmd’ and enter) and go to VirtualBox folder.

2-3. List available cameras.

The result should be like below. In case of Surface Pro 4, it has 2 cameras (front and rear).

2-4. Attach webcam(s) you want to use. The number at the end of the line specifies the camera. In this example, if you want to attach the front camera, type like this:

* Replace “Ubuntu 16.04.3” with your guest OS name.
* You can attach multiple cameras if you want.


3. Verify (Ubuntu Guest)
In case of Linux, cheese is handy to test webcam functionality.

3-1. Install it if it’s not already.

3-2. Then, just type ‘cheese’ to launch. You should be able to see a video stream in newly opened ‘Cheese’ window.


4. Verify (Mac OS Guest)
In Mac OS X, I used ‘Photo Booth’ application to verify.

4-1. Launch ‘Spotlight Search’ by clicking the magnifying glass icon in the upper right corner of the screen.

4-2. Type ‘Photo Booth’ and enter to launch. You should be able to see a video stream in ‘Photo Booth’ window.


[1] Oracle VM VirtualBox User Manual 9.7. Webcam passthrough
[2] VirtualBox Download page
[3] Install VirtualBox Extension Pack on Linux and Windows
[4] Connecting a webcam to a VirtualBox guest OS