GSS Mahadevan's Blog

Saturday, August 23, 2014

My Mum's Blog

Today started a blog page on my mum's recipes at this blog site

Sunday, August 17, 2014

I was planning a Home Access Control System for lots of days. Finally got some time over past few months. Finally I finished version-2 of my Home Access Control System.

Current version uses Raspberry for controlling the Main Door lock. Client are: Smartphones and RFID keys.

At present, I have written Android client for controlling. But the system is capable to handle iOS/WinPhones.

I will add more photos and code in coming weeks. More info can be found at at this place

Monday, July 29, 2013

Android Application Bluetooth Low Energy Scanner

After installing the Android 4.3 on Nexus-4, one can write the Bluetooth Low Energy (BLE) programs on Android platform. As still no official samples are available from LG/Google on the SDK samples, I tried to dig through available the Java-docs for new SDK and write an Android-App for scanning all BLE devices available in vicinity.

To use this application, we need following:

Any Android with 4.3 installed and have BLE HW support ( that means the mobile phone should support Bluetooth 4.0)
For getting list of scanned devices, we have two options:

Have real BLE devices (like BLE dongles, chips, SoC, etc)

We need to have a firmware image that allows us to start the discoverability on the device.

Have another Android 4.3 phone with BLE enabled and discovery enabled

I have TI's CC2540DK-MINI development kit and NordicSemi's nRF51822 Development kit. TI's kit comes with a KeyFrob and USB-based-BLE-devices and USB-based firmware loader. For current project, I am using TI's kit's KeyFrob as my BLE device (that I am scanning from Android phone).

I have loaded the project code to the project site.
You can try the same application using the Android application download link

Here is screen shot

Sunday, July 28, 2013

New Android 4.3 Manual Update on Nexus-4 does not contain OpenCL support

After successful update of Android 4.3 on Nexus-4 phone, I have found that my OpenCL Android applications are not running in system. After some initial lookup/debug of problem using:

adb logcat is indicating that libOpenCL is not loaded
abd shell ls -l /system/lib/libOpenCL.so is not returning any entries

So it seems that google/LG will take some more time to make the OpenCL work on Android 4.3

Update of Nexus 4 with Android 4.3

As official OTA update for Android 4.3 from google is not still available on Nexus-4 (4.3 is released on 24-Jul-2013), I thought that let me try manual (risky approach & could brick phone) uploading using various following links:

Disclaimer: Please note that normally one should wait for OTA updates from Google. This manual approach is risk prone and may brick your device. If you try this approach, please keep in mind that you may brick your device & I am not responsible if any thing happens to your device :)

BTW using this procedure, all old information/application in phone will be still intact (unless otherwise something extra things were done).

Prerequisites

You have non rooted Nexus 4 and it is in Android version 4.2.2 and you have PC/Laptop with Windows-XP-SP3 (it may work with other latest window versions, but I have not worked with them for this operation)
You have latest Android SDK tools.

Your adb should have following version:

adb version : Android Debug Bridge version 1.0.31
Note: adb help will not show sideload command while issuing adb help. So please ensure that we have above adb version. The adb sideload command will work when the phone is in recovery mode

You have properly installed windows drivers on computer so that you can see devices from 'adb devices'
You have downloaded the Android 4.3.3 release zip file for Nexus-4 (stock with no ROM modiifcations) from following link . If you other devices other than Nexus-4, please check for the update zip at that site.

After download rename the file to update.zip
Length of file: 177,524,837 , MD5: a62d34fef0fda5a512ffdc87b59ed9d4

While doing update, you may need to add extra USB device drivers for adb sideload

Add following entries in your Drive:\opt\Android\android-sdk\extras\google\usb_driver\android_winusb.inf

In section [Google.NTx86]

%CompositeAdbInterface% = USB_Install, USB\VID_18D1&PID_D001

In Section [Google.NTamd64]

%CompositeAdbInterface% = USB_Install, USB\VID_18D1&PID_D001

You need to do this in case when your adb sideload says no devices found. Above USB VID(Vendor ID) and PID( Product ID) are for Nexus 4.
If your device is not Nexus-4, the VID & PID might change and you get them via (please ensure that you are connected to PC via USB cable and the phone is in recovery mode -- go to that mode by: adb reboot bootloader & procedure below):

My Computer -- Manage -- Device Manager -- Other Devices -- Nexus 4 -- Properties -- USB VID & PID from Combox over there

Update procedure

Goto boot recovery mode:

Without SDK tools:

Stop Android phone
Press Volume-UP and Volume-Down and Power buttons simultaneously

With ADB

adb reboot bootloader

Use Volume buttons to select 'Recovery Mode'

Use power button to select the operation

Phone should show Android Icon with Exclamation mark. Press Volume-UP and Power buttons
Use Volume buttons to select 'Update from ADB'

Use power button to select the operation

Then it will show load using adb sideload

Ensure that you have configured Nexus 4 Recovery mode USB drivers as mentioned above for your Nexus 4 device

Then from PC issue following command

adb sideload c:\update.zip
It will take few minutes for doing updates (if everything is went fine).

Hope this helps who wants to get 4.3.3 updates and can't wait till google OTA update comes officially and want to take risk :)

Tuesday, June 18, 2013

Got working Arduino Pro Mini for Home Automation work - 1

For my home automation projects, I have been doing lots of R&D on various factors like:

Low cost MCU and MCU related board (commercially available)
Low power consumption in deep sleep (may not be the best , but reasonable low current consumption, so that MCU can withstand power outages)

Lots of cheap boards are there. For the time being I have chosen following Arduino boards

Arduino Pro Mini clone for 4.25$ per board with free shipping

Cheap availability of wireless connectivity solutions

Bluetooth 4.0

In coming future, I would be using BLE-Soc chips likeNordic nrf51822 and TI's cc2540 & cc2541 -- as we have cheap assembled boards at various internet shops (like alibaba, dealsextreme, ebay, etc) .These boards typically come for 6 to 12$

Zigbee

I tried initially, but their board's cost is high very high even at above shops and difficult solder because of QFN-soldering, wireless antenna's design, etc.

Proprietary wireless protocol

I found Nordic radio transceiver NRF24L01+ at 2.4GHz spectrum at following site for around 1$ per board

Free compiler, open source libraries & knowledge base in net. If not free some trial based compiler for doing R&D (like cc254x chips).

Arduino fits the bill, but their overall solution costs more than 15 to 20$ before an year back (with my research at that point of time). So I dropped Arduino idea and looking for other solutions. Recently I casually browsed Alibaba site and found that I can get a reasonably powered Ardunio for less than 5$ and wireless connectivity for another 1$. So brought these items and finally started doing first helloworld on this boards.

Here are pictures for this board

This is for connecting this board with typically USB-to-Serial-Dongle(Prolific based) and correpsonding RS232 TTL convertor

This is showing minimal connections needed for powering and burning the program to Arduino. These yellow wires do connect to above USB-RS232-Dongle (RX & TX appropriately)

Board view from top view with an empty board on side

Connections from Arduino Board to RS232

Please ensure that you connect serial port cross-connection like following:

Board-Longer-Side RXI to RS232 TX

Board-Longer-Side TXD to RS232 RX

Arduino IDE Options

Select proper Serial port
Select board as either of these boards. For my both voltages have worked out

'Arduino Prop or Pro Mini (5V, 16MHz) w/ Atmega328'
'Arduino Prop or Pro Mini (3.3 V, 8MHz) w/ Atmega328'

Select Programmer as 'Arduino as ISP'

Actions need to be taken while pressing Upload from IDE

As current setup does not use DTR/RTS on RS232 and only uses RX/TX (from USB to Rs232 converter), we need to press reset button just before the flashing (i.e., when console logs shows lines something like following in verbose-burning-mode-preferences)

Using Port : /dev/ttyUSB0

Using Programmer : arduino

Overriding Baud Rate : 57600

avrdude: Send: 0 [30] [20]

For more details on why we need to press reset button, refer following section Automatic (Software) Reset in given link

Problems/Issues faced

Serial Port not detected in Linux

Run as root, then the Arduino IDE recognizes the Serial port . Select appropriate serial port from output of 'dmesg' command in linux.

Flashing Issues

After selecting the board as 'Arduino Prop or Pro Mini (5V, 16MHz) w/ Atmega328' and correct serial port. After trying to flash image to board has given following error messages.

Binary sketch size: 2,654 bytes (of a 30,720 byte maximum)avrdude: stk500_recv(): programmer is not responding

Now enable the verbose upload option via File -- Preference --'Show verbose output during' = 'burning' .

After this step , I got following messages

Binary sketch size: 2,654 bytes (of a 30,720 byte maximum)

**/arduino-1.0.5/hardware/tools/avrdude -C/opt/arduino-1.0.5/hardware/tools/avrdude.conf -v -v -v -v -patmega328p -carduino -P/dev/ttyUSB0 -b57600 -D -Uflash:w:/tmp/build5308589158935848821.tmp/ASCIITable.cpp.hex:i

avrdude: Version 5.11, compiled on Sep 9 2011 at 16:00:41

System wide configuration file is "**/arduino-1.0.5/hardware/tools/avrdude.conf"

User configuration file is "***/.avrduderc"

User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/ttyUSB0

Using Programmer : arduino

Overriding Baud Rate : 57600

avrdude: Send: 0 [30] [20]

avrdude: ser_recv(): programmer is not responding

avrdude: stk500_recv(): programmer is not responding

avrdude done. Thank you.

Another error which slightly different at end

Using Port : /dev/ttyUSB0

Using Programmer : arduino

Overriding Baud Rate : 57600

avrdude: Send: 0 [30] [20]

avrdude: Recv: . [00]

avrdude: stk500_getsync(): not in sync: resp=0x00

avrdude done. Thank you.

As this not typical USB based driver (which is available in little costlier Arduino boards) and I am using hard coded RS232 wiring, I tried to flash the image by pressing the reset button on the board. This made the flashing to occur successfully. Actually if we reset the board, MCU waits for flashing-data from RX/TX pins few seconds. If no recognized flashing data comes to RX/TX pins, MCU will boot with previous programm that is there in flash. One has to find appropriate time to press reset button -- this timing can be assisted by putting verbose-burning-option.
So successful flash sequence is shown as:

Binary sketch size: 2,654 bytes (of a 30,720 byte maximum)

***/arduino-1.0.5/hardware/tools/avrdude -C***/arduino-1.0.5/hardware/tools/avrdude.conf -v -v -v -v -patmega328p -carduino -P/dev/ttyUSB0 -b57600 -D -Uflash:w:/tmp/build5308589158935848821.tmp/ASCIITable.cpp.hex:i

avrdude: Version 5.11, compiled on Sep 9 2011 at 16:00:41

System wide configuration file is "***/arduino-1.0.5/hardware/tools/avrdude.conf"

User configuration file is "***/.avrduderc"

User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/ttyUSB0

Using Programmer : arduino

Overriding Baud Rate : 57600

avrdude: Send: 0 [30] [20]

avrdude: Recv: . [14]

avrdude: Recv: . [10]

AVR Part : ATMEGA328P

Chip Erase delay : 9000 us

PAGEL : PD7

BS2 : PC2

RESET disposition : dedicated

RETRY pulse : SCK

serial program mode : yes

parallel program mode : yes

Timeout : 200

StabDelay : 100

CmdexeDelay : 25

SyncLoops : 32

ByteDelay : 0

PollIndex : 3

PollValue : 0x53

Memory Detail :

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