Setting Up Bluetooth OOB Pairing with NFC on Raspberry Pi

This post shows steps to setup Bluetooth Out-Of-Band (OOB) pairing using NFC [1] on Raspberry Pi using nfcpy [2]. The goal is to pair a phone and Raspberry Pi by just touching each other.

 

Prerequisites (parentheses indicate my environment)

 

Steps
1. Installation
1-1. Install nfcpy.

1-2. Verify installation by running the module.

The output should be like this:

1-3. As the output suggests, copy line 11 above and execute it.

1-4. Reboot the system.

1-5. After reboot, run the module again.

This time, the output should be like this:

 

2. Setting up Bluetooth OOB Pairing
2-1. Download example code [3].

2-2. Create NDEF data [4] for Bluetooth OOB pairing [5].

Note: Replace “XX:XX:XX:XX:XX:XX” with your Raspberry Pi’s Bluetooth device address.

2-3. Write NDEF data to NFC adapter [6].

2-4. Open another terminal and launch Bluetooth command line interface.

2-5. Enable the pairing agent.

2-6. Set the agent as default agent.

2-7. Enable discoverable mode.

 

3. Test
3-1. Enable NFC on the phone.

3-2. Move the phone close to the NFC adapter.

3-3. Allow the pairing request on the phone.

3-4. Allow the service authorization on Raspberry Pi if requested.

 

 

References
[1] Bluetooth Secure Simple Pairing Using NFC – NFC Forum
[2] Python module for near field communication – nfcpy
[3] nfcpy – GitHub
[4] NFC Data Exchange Format – nfcpy
[5] make btcfg – nfcpy
[6] emulate – nfcpy

 

 

Setting Up Wi-Fi Simple Configuration with NFC on Raspberry Pi

This post shows steps to setup Wi-Fi Simple Configuration with NFC adapter on Raspberry Pi using nfcpy[1]. The goal is to enable “tap-to-connect” a NFC enabled phone with a Wi-Fi access point [2].

 

Prerequisites (parentheses indicate my environment)

 

Steps
1. Installation
1-1. Install nfcpy.

1-2. Verify installation by running the module.

The output should be like this:

1-3. As the output suggests, copy line 11 above and execute it.

1-4. Reboot the system.

1-5. After reboot, run the module again.

This time, the output should be like this:

 

2. Setting up Wi-Fi Simple Configuration
2-1. Download example code [3].

2-2. Create NDEF data [4] for Configuration token [5].

Note: Replace “NETWORK_NAME” and “PASSWORD” based on your environment.

2-3. Write NDEF data to NFC adapter [6].

 

3. Test
3-1. Enable NFC on the phone.

3-2. Move the phone close to the NFC adapter.

3-3. Allow to connect if the phone asks for permission.

 

 

References
[1] Python module for near field communication – nfcpy
[2] WPS adds NFC “tap-to-connect” for simple set up – Wi-Fi Alliance
[3] nfcpy – GitHub
[4] NFC Data Exchange Format – nfcpy
[5] make wificfg – nfcpy
[6] emulate – nfcpy

 

 

Changing a Bluetooth Device Address on Raspberry Pi

This post shows how to change Bluetooth device address on Raspberry Pi.

Bluetooth device address (aka BD_ADDR, Bluetooth MAC address) is a 48-bit identifier assigned to each Bluetooth chip. Whether it can be changed is depends on each chip. Fortunately, Raspberry Pi’s on-board Bluetooth chip (Cypress/Broadcom) allows device address change.

 

Assumptions
Raspberry Pi board with on-board Bluetooth chip (e.g. Raspberry Pi3 B+Raspberry Pi Zero W)

 

Steps
1. Prep
1-1.Install prerequisite package.

1-2. Download the archived file of bdaddr tool. [1][2]

1-3. Extract the archive file.

1-4. Make.

 

2. Bluetooth Address Change
2-1. Check the original Bluetooth address..

2-2. Change Bluetooth device address.

The result should be like this:

2-3. Reset hci device.

2-4. Also, restart bluetooth service.

 

3. Verify
3-1. Check the change with bdaddr tool.

3-2. Check the change with bluetoothctl.

 

References
[1] Change your bluetooth device mac-address
[2] Wget: Error 403- Can I get around this?

 

 

Qt Creator Cross Compiling Environment for Raspbian Stretch using QtRpi


This post shows how to create Qt Creator cross development environment on Ubuntu PC for Raspbian Stretch by using QtRpi. Although QtRpi does not officially support Raspbian Stretch [1], additional few steps make it possible to create the cross development environment for Stretch. (For Raspbian Jessie, please see this post.)

 

Contents
– Assumptions
– Steps
1. Host Preparation (Ubuntu)
2. QtRpi Installation
3. Deploy to Raspberry Pi
4. Raspberry Pi Configuration
5. Qt Creator Configuration
6. Verify Cross Compiling Environment
– Reference

 

Assumptions
Here are some assumptions for the steps below.

  • Ubuntu Linux running on host PC
  • Raspbian Stretch running on target Raspberry Pi
  • Qt Creator running on host PC
  • SSH access from host PC to target Raspberry Pi

In this post, the versions I use are below:

  • Ubuntu 18.04 (host)
  • Qt Creator 4.6.1 (host)
  • Raspbian Stretch April 2018 version running on Raspberry Pi 3 (target)
  • Qt 5.7.0 (target)

 

Steps
1. Host Preparation (Ubuntu)
1-1. Install dependencies.

1-2. Configure environment variable for Qt version. As of writing this, QtRpi supports only 5.6.2 and 5.7.0. [2]

1-3. Configure environment variable for Raspberry Pi model. For different models, check the official site.

1-4. Configure environment variable for target IP address.

1-5. Generate SSH key. Just press enter when you asked about pass phrase.

1-6. Copy the key to the target so that you can log in without requiring a password afterwards.

 

2. QtRpi Installation
2-1. On host, download QtRpi from GitHub.

2-2. Then run “init-qtrpi-minimal.sh” script. This will take a while.

 

3. Deploy to Raspberry Pi
Before start the deployment script, one modification is required since a name of a package has been changed. [3]

3-1. Open the deployment script file.

3-2. Look for the line below and replace “libinput5” with “libinput10”.

After the change, the line should be this:

3-3. Then, run the deployment script.

 

4. Raspberry Pi Configuration
4-1. Login to Raspberry Pi.

4-2. Create symbolic links since some libraries has changed names in Stretch. [4] [5] [6]

4-3. Copy font files.

Note: This step is a workaround for font display. (see troubleshoot in the previous post for detail.)

 

5. Qt Creator Configuration
5-1. Device Configuration
5-1-1. Launch Qt Creator on host.
5-1-2. Navigate to “Tools” > “Options…”
5-1-3. In Options window, select “Devices” from left side bar.
5-1-4. Select “Add…”
5-1-5. Double click on “Generic Linux Device”

5-1-6. Enter information below into “New Generic Linux Device Configuration Setup” window.
Configuration name:

IP address:  (your RPi’s IP address)

Username:

Authentication type:

5-1-7. Click on “Next”, Then “Finish”. Then, it will automatically start “Device Test”.
5-1-8. Click “Close” to close “Device Test” window.

5-2. Debuggers
5-2-1. In Options window, select “Build & Run” from left side bar.
5-2-2. Click on “Debuggers” tab
5-2-3. Click on “Add” button
5-2-4. Put information below:
Name:

Path:

 

5-3. Compilers
5-3-1. Click on “Compilers” tab
5-3-2. Navigate to “Add” > “GCC” > “C”
5-3-3. Enter information below:
Name:

Compiler Path:

5-3-4. Navigate to “Add” > “GCC” > “C++”
5-3-5. Enter information below:
Name:

Compiler Path:

 

5-4. Qt Versions
5-4-1. Click on “Qt Versions” tab
5-4-2. Click on “Add…”
5-4-3. Navigate the qmake path:

5-4-4. Enter below as “Version name”.

5-4-5. Click on “Apply” button

5-5. Kits
5-5-1. Click on “Kits” tab and then “Add” button
5-5-2. Enter (or select) information below:
Name :

Device Type:

Sysroot :

Compiler: C:

Compiler: C++:

Debugger :

Qt Version :

5-5-3. Click on “Apply” button, then “OK”.

 

6. Verify Cross Compiling Environment
Let’s check if everything is OK by building a sample project on host and executing it on RPi.

6-1. “File” > “New File or Project”
6-2. “Application” > “Qt Qucick Application”, then click on “Choose…” button.
6-3. Enter project name and click on “Next”.
6-4. Click on “Next” on “Define Build System”.
6-5. Select “Qt 5.7” and click “Next” on “Define Project Details”.
6-6. Check on “Rpi 3” and click “Next” on “Kit Selection”.
6-7. Click on “Finish” button on “Project Management”.
6-8. Open .pro file from the project tree.
6-9. Replace “Default rules for deployment” portion with the two lines below.

6-10. Select “Projects” icon on left side bar.
6-11. Click on “Rpi 3” under “Build & Run”.
6-12. Click on “Run” icon on the left side bar.

 

References
[1] QtRpi Requirements – GitHub
[2] What versions of Qt is available? – QtRpi FAQ
[3] deploy-qtrpi.sh “unable to locate libinput5” #69 – qtrpi – GitHub
[4] Games that uses libGLESv2.so doen’t work in raspbian stretch – raspberrypi.org
[5] ArchLinux Qt eglfs – raspberrypi.org
[6] Linking the Application to the Static Version of Qt – Qt Documentation

 

 

Enabling Equalizer on Raspberry Pi using ALSA equal Plugin


This post shows how to setup a system wide equalizer on Raspberry Pi using ALSA equal plugin. Below are my setup.

  • Raspberry Pi3 B+ with Raspbian Stretch (2018 April version)
  • 3.5 mm plug Speaker

 

Contents
– Assumptions
– Steps
1. Equalizer Plugin Installation
2. ALSA Configuration
3. Play audio
4. Verify Equalizer
– Notes
– Reference

 

Steps
1. Equalizer Plugin Installation

 

2. ALSA Configuration
2-1. Create .asoundrc.

2-2. Add the lines below, save and close the file.

2-3. Reload .asoundrc.

 

3. Play audio
Play a sample sound file in a loop for testing.

Note: Press Ctrl+C to exit.

 

4. Verify Equalizer
Adjust the equalizer by using alsamixer command.

The sound from Raspberry Pi’s speaker should change as you change the equalizer values.

 

Notes
Since Raspbian Stretch, Bluetooth audio is handled by ALSA using bluez-alsa [2]. So if A2DP sink is enabled, this equalizer can be also applied on Bluetooth audio.

 

References
[1] Raspbian: the great Equalizer
[2] Raspbian Stretch has arrived – Raspberry Pi Official Blog