[Android-NDK] Creating shared library and using them in Android Oreo 8 and 8.1

[Android-NDK] Creating shared library and using them in Android Oreo 8 and 8.1

In this post I’m going to show how to build shared library for android and using them. I’m using Ubuntu 16.04 LTS running inside a VM and Android Studio 3.2.1 running on windows 10.

Step1: Setting up the environment

  • Get Android NDK (https://developer.android.com/ndk/downloads). At the time of writing this post I’m using android-ndk-r19c-linux-x86_64.zip
  • Unizp the downloaded file and change directory into android-ndk-r19c. In this directory you should see a binary called “ndk-build”. We will use this binary to build the shared library.
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Logstash JSON filter to detect events

Logstash JSON filter to detect events

I wanted to filter out JSON encoded data coming from OSSEC client to logstash and then forward the parsed JSON to clients connected over websocket. This filter could be useful for detecting and sending alerts on occurrence of certain events, so I wrote a filter to parse only the JSON encoded data and discard any other data.

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PIC32 and ILI9328 TouchScreen User Interface using Microchip Graphic Library

PIC32 and ILI9328 TouchScreen User Interface using Microchip Graphic Library

I developed this user interface (UI) using pic32, microchip GDD tool and microchip graphic library.

I recorded the test in this video

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Testing ILI9328 2.8″ TFT (Touch Screen) with PIC32MX795F512L

Testing ILI9328 2.8″ TFT (Touch Screen) with PIC32MX795F512L

performed a simple test to interface ILI9328 2.8″ TFT (Touch Screen) with PIC32MX795F512L, later on I also wrote SPI based touchscreen driver for analog devices ADS7843. The main program checks for the data available pin and if touchscreen data is available it reads through SPI:

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Testing Texas Instruments keyfob (CC2540) with custom android app

Testing Texas Instruments keyfob (CC2540) with custom android app

I build a test android app to communicate with Bluetooth Low Energy keyfob CC2541 kit from Texas Instruments.

The end project was to design and develop a small size anti-theft/forget device and mobile phone application which can communicate with the device. This device can be placed inside wallet, briefcase, etc  and on link loss the app can alert mobile phone user about lost item. And device should be able to run on a coin cell for duration of 8-12months.

During Schematic and PCB design I also added accelerometer and intervalometer for future application. Unfortunately the project never got off the ground but app and PCB was designed and developed.

pcb schem

inductor, capacitor and resistors used were 0201 size.

intervalometer for taking picture on phone using the device.

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MCP3208 A/D converter on Pinguino 18F2550

MCP3208 A/D converter on Pinguino 18F2550

If you are working on Pinguino and want to use MPC3208 ADC for reading analog sensors then the following code will be helpful to you. This code is based on arduino example, I have ported it to pinguino 18F2550.

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Interfacing 16×2 LCD with Pinguino 18F2550

Interfacing 16×2 LCD with Pinguino 18F2550

Recently in one of my project I needed to add 16×2 LCD so I tried to use Pinguino LCD library provided in the example folder of the IDE. But for some reason it didn’t worked, so I downloaded HD44780 datasheet and build my own LCD interface program.

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Open Source Tracking Platform – DhruvTracker

Open Source Tracking Platform – DhruvTracker

In every few days I am getting constant news from TV, internet and newspapers that some or the other group has developed a vehicle tracking system which can track vehicles online using GPS and GSM. From a year or so I also had a thought to build a tracking device but I was not able to build it at that time. Few days back I had a need to put a tracking device in my car for surveillance purpose so instead of buying one I thought to build one and now since there are lots of people working on this so I have started to build an open source tracking platform which will help other individuals and developers to build their own tracking system.

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FM Transmitter

FM Transmitter

This is a simple FM transmitter. It have an audio amplifier stage, modulation stage and finally an isolation stage of antenna and tank. All the components used are easily available. For making inductor use 28 AWG wire (the same wire which connects harddrive with motherboard), strip off the copper wire so you’ll be only left with wire and no outer cover. Now wound this wire (5 turns) on refill of a ball pen (the plastic tube that holds ink).

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