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RoadTests & Reviews

12 Posts authored by: amgalbu Top Member
In these post I will note down my impressions about the components of the kit I used in my project, namely MSP430FR4133 LaunchPad Development Kit (MSP-EXP430FR4133) TPS92512 Buck Regulator   MSP430FR4133 LaunchPad Development Kit (MSP-EXP430FR4133) The out-of-the-box impression has been very good. Just providing power by simply connecting the provided USB cable to a PC or a USB charger, makes the pre-installed demo application to run. This gives you a good overview of the display capabili ...
This is the last post of this roadtest The initial idea was to transmit a unique code using the visible light. This has applications in indoor navigation (in museum, shops, etc)   I got a working prototype (I will publish a video in the next days), with several limitations   1. the algorithm used is tailored for my smartphone, so I don't expect it to work on another model. In particular, the algorithm is affected by the frame rate and by the exposure time. Also, not all the possible ...
After introducing the structure of a camera-based Android application, let’s have a look at the algorithms implemented to decode VLC data       smooth The smooth function applies a moving average to the data captured by the camera according to the formula     private void smooth() {     int[] output = new int[numSamples];     int oldestSample = 0;     for (int i=0; i<numSamples; i++)     {   ...
amgalbu

LEDRoadTestPlus - Post 9

Posted by amgalbu Top Member Dec 28, 2015
The receiver of the data encoded and transmitted by the MSP430 LaunchPad  will be decoded by an Android smartphone running a dedicated app The app basically captures camera frames in preview mode and analyzes data. In this post, I will talk a little about the basics of Android camera development, and in the next post I will talk about algorithms implemented to decode data sent through visible light Before starting development on an application with the Camera API, you should make sure you ...
amgalbu

LEDRoadTestPlus - Post 8

Posted by amgalbu Top Member Dec 21, 2015
Here is the video of the VLC transmitter   ...
amgalbu

LEDRoadTestPlus - Post 7

Posted by amgalbu Top Member Dec 20, 2015
In this post the final version of the transmitter will be introduced The transmission of the data is performed inside the Timer1 interrupt routine. Timer1 is initialized to run at 100 us by the following code   // TimerA1 UpMode Configuration Parameter Timer_A_initUpModeParam initUpParam_A1_PWM = {              TIMER_A_CLOCKSOURCE_SMCLK,              // SMCLK Clock S ...
amgalbu

LEDRoadTestPlus - Post 6

Posted by amgalbu Top Member Dec 13, 2015
In this post we will see some specs about the MSP430FR133 Timers, because a timer will generate the PWM signal that drives the LED There are two instances of Timer_A that you can use (i.e. Timer_A is not actually a single timer, but two timers – 0 and 1). The naming is a little confusing: Timer0_A3 and Timer1_A3. Why the “3” on the end? That refers to the number of interrupts that each timer can trigger (these are called capture/compare registers, which we’ll get into ...
To start developing my app on the LaunchPad, the first thing to do is to install the TI Code Composer Studio (CCS) The setup can be downloaded from TI website http://processors.wiki.ti.com/index.php/Download_CCS   The installation is very simple and troubles-free. At the end, I also downloaded the code of the firmware installed by default on the LaunchPad from MSP430FR4133 LaunchPad Development Kit - MSP-EXP430FR4133 - TI Tool Folder   I imported the project by clicking Project -& ...
After deciding how to transmit the preamble and the bit, in this post I will explain how I want to transmit a byte. Since I expect to be in front of a very noisy channel, I will adopt a error-detection-and-correction code like the Hamming 7,4 The notation (7,4) means that 7 bits are required to send 4 bits of information. The extra bits allow to detect and correct a flipped bit among the 7 bits transmitted The following general algorithm generates a single-error correcting (SEC) code for any ...
The whole project proposed in this roadtest is based on  a particular technology used in CMOS camera sensors: Rolling Shutter Global shutters, which are commonly implemented on CCD sensors (although CMOS variants exist), expose all pixels on the sensor simultaneously and gather incoming light over all pixels for the exposure time (Te). After collection has stopped, the data is transferred. Rolling shutters on the other hand, consecutively expose and read-out individual rows of pixels in ...
amgalbu

LEDRoadTestPlus - Post 2

Posted by amgalbu Top Member Nov 26, 2015
The TPS92512EVM-001 evaluation module (EVM) helps designers evaluate the operation and performance of the TPS92512HV buck switching regulator designed for high-current LED-drive applications. The TPS92512HV device is designed to control the drive of high-brightness light emitting diodes and features a wide input voltage range (4.5 V to 60 V), PWM dimming capability, analog dimming capability, adjustable/syncable switching frequency, and input undervoltage protection.     The board i ...
amgalbu

LEDRoadTestPlus - Post 1

Posted by amgalbu Top Member Nov 16, 2015
The project I want to build during this roadtest is a Visible Light Communication (VLC) system between a LED driven by the TPS92512 board and an Android smartphone The idea behind VLC is very simple: light bulbs are pervasive, have ample access to power, and are often ideally positioned for sensing applications. So, why not transform lighting sources into landmark beacons that can be used, for example, for indoor localization? If each light bulb could uniquely identify itself to nearby mobile d ...

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