A Modular-Reconfigurable Presentation System Design and Implementation Based on LEDs


This project “A modular-reconfigurable presentation system design and implementation based on LEDs” consists of a LED screen design and development at hardware and software level, features cited in the name of this project.

In order to approach its design, we have started making an art state investigation, through which some similar projects to this one have been looked into.

Next, we carried out a hardware design and implementation. During this stage two hardware versions were developed.

Then, the software design and development have taken place. A first software stage is executed by the PC and the other stage is executed by the microcontroller. During this phase of the project we have developed many block versions which made the software architecture up.

Later, different hardware and software level tests were performed.

Finally, some full system tests were also carried out.

The project has been developed in seven phases as shown as per below chart.


As said before, the presentation system is made up of a hardware and software structure. The hardware structure is constituted by some elements, from which It is emphasized the relevant LED screen and the development board that includes a microcontroller. The software structure has been coded at PC and within a microcontroller too. This main project aim has been to desing a modular system presentation and resettting based on LEDs.

The main objective is broken down into four purposes

  • Draw up a modular and reconfigurable LED screen.
  • Develop a microcontroller software to allow using the LED screen.
  • Develop a software by PC to display a photo on the LED screen.
  • Develop a software by PC to display a video on the LED screen.

It is relevant to clarify that every pixel of this screen is encoded by 24 bits. These bits are G7, G6, G5, G4, G3, G2, G1, G0, R7, R6, R5, R4, R3, R2, R1, R0, B7, B6, B5, B4, B3, B2, B1, B0 as shown as per below chart.


The hardware architecture is a set of physical blocks through which this system is based on. In the basis of the system outcome and the hardware requirement some hardware architecture blocks have been defined.  The hardware architecture that makes up the bits is described as per below.

  • PC: It executes processor-transmitter software blocks.
  • USB-serial converter: It Carries GRB bits forward to microcontroller.
  • Microcontroller: It executes receiver-presentation software blocks.
  • Logic level converter: It goes the amplitude up from the PWM to the microcontroller pins GPIO output, from 3.3 [V] to 5 [V].
  • LED screen: It is made up of LED modules. Each module has 25 LEDs. For LED modules manufacturing purposes some LEDs SMD 5050 have been chosen, these LEDs mix an integrated circuit enclosed in. This circuit incorporates a signal amplifier and depending on the manufacturer also a sequential logic block. This way, the signal is empowered through each LED and 24 bits data is addressed to, from which 8 bits are related to sub LED G, 8 are linked up  to sub LED R and 8 bits are connected to sub LED B. So that, color and bright are separately controlled for every LED.
  • Power supply: It is setup into a star topology. Supplies 23 [A] to the system.

By means of next chart, hadware arquitecture is shown as per below.


The LED screen is composed by four module rows of LEDs, each module row is assigned by a data line as per below.


For the LEDs screen, it has been decided to use several parallel data lines, due to it aims to overcome a LEDs handicap. This handicap consists of when broadcasting a 30 [frames/s] – streaming video. It does not allow to connect more than 1024 LEDs into serial architecture. Essentially because of timing  purposes. Which are exposed by means of this reasoning: If the rate to broadcast this video is 30 [frames/s], this indicates every 0.033 [s] a frame to display on LEDs is loaded. Tframe = 0.033 [s].

On the other hand, Tbit=1,25 [µs] which is a value forced by the LEDs.

As discussed earlier in this report, 24 bits are related to every single pixel, immediately after sending all bits towards the LEDs, a time must be saved for a 50 [µs] reset. This way, sending period expression, it is as it follows:
Tsend = ( 1.25 [µs/bit] x 24 [bits/pixel] x 1024 [pixels] ) + Treset = 0.03077[s]

Checking out on, Tsend < Tframe.

That is, this limitation resides in central premise that, sending time cannot be greater than frame time, whether more than 1024 LEDs are connected in cascade architecture, it is need a time greater than frame time, therefore it breaks that premise.

For the case in which the rate to broadcast this video is 60 [frames/s], could be linked into  cascade connecting factors up to 512 LEDs.

Therefore, there is an inversely proportional relationship between the video rate broadcast and the number of LEDs to be connected in cascade.

The software architecture is composed by two phases, one developed to PC and another to microcontroller.

In the PC phase, processor and transmitter blocks have been processor defined. This stage consists about reproducing a video signal and executing some processor and transmitter blocks for each frame from the video signal.

In the microcontroller phase, it is been defined both receiver and presentation blocks. In this stage continuously some bytes are received through UART and are shown on the screen.

The next diagram shows the software architecture.


Now we describe the software blocks functions

  • Processor block: This block extracts the pixels from each frame and it organises them according to the data line of LED screen. Then, it moves these GRB bits to the corresponding bit of data line and then it stores those GRB bits in an array.
  • Transmitter block: This block is in charge of transmitting in serial the array obtained in the processor block.
  • Receiver block: This block receives in serial the bytes of array transmitted by the transmitter block. That array contains sorted pixels according to line mapping data on the LEDs screen.
  • Presentation block: This block carries the symbols “1” or “0” to GPIOs MCU. Those symbols are generated as from extracted pixels from each frame. It should be clarified that GPIOD pines within microcontroller are linked up to the LEDs screen.

The symbols are illustrated below.


Consequently, it is graphically represented by the way different blocks interact one another.


For a video composed by n frames, first the processor block is run for all the pixels within frame 1, then transmitter block sends GRB bits associated to frame 1 towards MCU. After that, receiver block is run for frame 1 and while presentation block shows GRB frame 1 bits on the screen, also GRB bits are received from frame 2.

This way, successively software blocks are run for video n frames.

This system has been tested projecting a video composed by 462 frames, this video is reproduced at 29.97[frames/s] speed. Next link illustrates that test.

Poster about Methodology for implementation of Synchronization Strategies for Wireless Sensor Networks


On the occasion of the II edition of the Symposium “Tell us your thesis” organized by the Universidad Politécnica de Madrid I created a poster summary of my thesis.

Both the thesis and the poster are entitled “Methodology for implementation of Synchronization Strategies for Wireless Sensor Networks“.

In the poster I intend to explain the process that every researcher and/or developer must carry out to add synchronization tasks to his Wireless Sensor Network.

180216 Methodology for implementation of Synchronizatoin WSN
Methodology for implementation of Synchronizatoin WSN

First of all it is needed to know what is the objective of the user application in which we want to add temporary synchronization.

Based on the application we will have some requirements to fulfill. That is, each application will have different requirements regarding timing, maximum permissible error regarding temporal precision or accuracy, network topology, message distribution method, battery consumption and life time objectives, hardware resources of different nature and different price, etc.

Since there are many options and possible ways, a methodology is needed that helps the researcher and/or developer to obtain a solution, in order to achieve a time synchronization in their wireless sensor networks, which is adapted to the needs of the application.

The development of this methodology is the objective of this doctoral thesis.

Download the poster with full resolution [PDF 18 MB]

STM32F4: Configurar el PWM con Timers


Un timer no es más que un contador. Es como un reloj que se usa para medir eventos temporales. Se configura a través de unos registros especiales y se puede elegir, entre otras cosas, su modo de funcionamiento.

En el ejemplo de hoy vamos a trabajar con la placa de desarrollo 32F411-DISCOVERY y nuestro objetivo va a ser aprender a configurar el TIM4 en modo PWM para controlar la intensidad de luz del led Naranja que viene integrado en la placa.

Esta placa está basada en el microcontrolador STM32F411 el cual dispone de hasta 11 Timers, de los cuales 6 pueden ser de 16 bits, y 2 de 32 bits, cada uno con hasta 4 canales de IC/OC/PWM o contador de pulsos. Además de 2 timers watchdog y un Systick Timer.

A través del software CubeMX activaremos el PWM Generation CH2 del TIM4 en la pestaña Pinout. Además de que asociaremos el pin PD13 la función alternativa de TIM4_CH2 (Channe2 PWM Generation CH2).


Con esto habremos conseguido dos cosas: por un lado configurar el canal 2 del Timer4 en modo PWM, y por otro lado asociar la salida del PWM al pin PD13, que es donde se encuentra el led naranja.

Tras esto pasamos a la pestaña Configuration y ahí configuramos el control del TIM4. Dentro de la pestaña de Parameter Settings hay 3 parámetros numéricos que debemos entender para configurarlos correctamente.

Prescaler (PSC – 16 bits value).

Con este valor podemos fijar la frecuencia del reloj asociado al Timer dividiendo la frecuencia del reloj de sistema.

Counter Period (AutoReload Register – 16 bits value).

Será el valor en el cual nuestro Timer saltará y nos avisará de alguna forma, ya sea reiniciándose o lanzando una interrupcion, etc.

Pulse (16 bits value).

Con este valor podemos fijar el ciclo de trabajo de nuestro PWM.

  • FreqTimer = FreqClock / (Prescaler + 1)
  • Prescaler = (FreqClock / FreqTimer) – 1
  • FreqPWM = FreqTimer / (CounterPeriod + 1)
  • Period = (FreqTimer / FreqPWM) – 1
  • Pulse = ((Period + 1) * DutyCicle) / 100 – 1
Queremos llevar a cabo dos ejemplos, por un lado queremos ver parpadear el led a varios ciclos de trabajo diferentes, y por otro lado queremos configurar un dimmer del led.

Ejemplo 1. Parpadeo del led.

Para el parpadeo del led queremos un periodo de trabajo lento para que nos de tiempo a ver esa conmutación entre encendido y apagado del led. Es por ello que hemos fijado el la Frecuencia del PWM a 1Hz. Luego, para hacer el resto de operaciones más fáciles hemos fijado la FreqTimer a 10 Khz. Con estos datos y usando las ecuaciones anteriores obtenemos:

  • APB2 timer clocks = 96 Mhz
  • Objetivo de PWM Freq = 1 Hz
  • Prescaler = 9599
  • Period = 9999

Para poder ver el cambio de parpadeo del led usaremos estos tres valores de Pulse (% Duty cicle). Estos cambios se podrían hacer en tiempo de ejecución.

  • Pulse: 99 (1%), 4999 (50%), 9899 (99%)

Ejemplo 2. Dimmer del led.

En este caso queremos que el periodo de trabajo sera muy pequeño para que las transiciones sean fluidas para el ojo humano. Es por ello que en este ejemplo hemos fijado la Frecuencia del PWM a 10 Khz. Luego, para hacer el resto de operaciones más fáciles hemos fijado la FreqTimer a 2 Mhz. Con estos datos y usando las ecuaciones anteriores obtenemos:


  • APB2 timer clocks = 96 Mhz
  • Objetivo de PWM Freq = 10 Khz
  • Prescaler = 47
  • Period = 199

Para poder ver un dimmer en el led recorreremos todos los valores posible de Pulse (% Duty cicle). Este cambio de valor hay que hacerlo en tiempo de ejecución.

  • Pulse: 0 (0%)-199 (100%)

Ejecución de los ejemplos

Una vez hemos generado la plantilla de código con CubeMX es momento de continuar en Eclipse.

Ahora debemos tener en cuenta que para que el PWM se ponga en funcionamiento tenemos que llamar a la función 

Y para poder hacer cambios en el valor de Pulse en tiempo de ejecución debemos llamar a la macro 

STM32F4: Interrupción externa


En el ejemplo de hoy veremos como asociar la generación de una interrupción externa al botón de usuario que hay en la placa de desarrollo 32F411-DISCOVERY. Después vincularemos a la atención de esa interrupción el toggle del led rojo.

Empezaremos configurando CubeMX, donde ya por defecto nos han puesto el GPIO PA0 configurado como GPIO_EXTI0 que indica que ese pin está configurado como interrupción externa. 

Para ello en la pestaña Configuration, dentro de la configuración de GPIO seleccionamos el pin PA0-WKUP y lo configuramos en modo External Interrupt Mode with Rising edge trigger detection, No pull-up and no pull-down.

Ahora debemos activar dicha interrupción bajo la pestaña Configuration, en la configuración de NVIC, debemos activar la línea EXTI line0 interrupt

Activando estas opciones en CubeMX nos generará el código correspondiente a la inicialización del sistema y activará la interrupción asociada a la linea 0, que en nuestra placa está vinculada al botón de usuario.

Si abrimos el fichero main.c y pinchamos sobre la definición de la función MX_GPIO_Init() podemos ver dos líneas al final del método que fijan la prioridad y activan la interrupción.

Si abrimos el fichero stm32f4xx_it.c podemos ver como ha aparecido una función para la gestión de la interrupción EXTI line0. Si pulsamos sobre la definición de HAL_GPIO_EXTI_IRQHandler(), nos lleva a otro método que limpia el flag de interrupción asociado al GPIO que ha generado la interrupción y llama a su callback asociado HAL_GPIO_EXTI_Callback(). Si vamos a la definición de esta última función vemos que está definida como tipo __weak y en un comentario nos dicen que debe ser implementada en espacio de usuario.

Como nosotros somos muy obedientes copiamos la definición de la función y nos lo llevamos al fichero gpio.c donde dentro del USER CODE 2 pegamos:

A este callback acudirá nuestro programa cuando se detecte una pulsación del botón. Ya que es recomendable hacer el mínimo de operaciones dentro del callback de una interrupción, en este callback sólo realizaremos la operación de toggle del led.

Para ello, dentro de este callback haremos la llamada a HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_14). De esta forma cada vez que se pulse el botón de usuario el led rojo de la placa debe conmutar.

Se deja al lector la resolución de varios problemas tales como el sistema antirebotes software que habría que poner asociado a las interrupciones que se generan a través del botón, o el problema asociado a que dentro del callback habrá que distinguir entre los diferentes GPIOs que generen interrupción.

Solo nos falta compilar, y debuguear en Ac6 STM32 C/C++ Application. Y con eso podremos ver conmutar el led rojo de la placa cada vez que pulsamos el botón de usuario.

STM32F4: Primeros pasos con el entorno de desarrollo


En el tutorial que vamos a llevar a cabo hoy veremos como instalar todas las herramientas de desarrollo para poner en marcha la placa de desarrollo 32F411-DISCOVERY. Una vez tengamos todas las herramientas instaladas procederemos a compilar y ejecutar un programa que haga parpadear un led.

Unos de los entornos de desarrollo integrado (IDE) que nosotros usamos en el B105 es eclipse. Para trabajar y poder compilar de forma cruzada para los STM32 existe una versión de eclipse que contiene todos los plugins y librerias necesarias para trabajar con dispositivos de STM llamada System Workbench for STM32 (SW4STM32). Es una herramienta gratuita que debéis descargar e instalar en vuestro ordenador. Para poder descargarla tendréis que registraros en la web. Es posible, que si no lo tenéis instalado todavía, tengáis que instalar Java en vuestro ordenador.



Ahora procedemos a descargar e instalar el software STM32CubeMX que nos es más que un generador de código de inicialización para los microcontroladores y plataformas de desarrollo de ST. Con este software podremos crear el código inicial con las capas de abstracción hardware con las que queremos inicializar nuestra plataforma.

cubmxAl instalar SW4STM32 y CubeMX se nos deberían instalar los drivers correspondientes para poder usar el programador integrado en la placa Discovery para el STM-Link v2 o v2.1.

Proyecto Toggle Led

Abrimos CubeMX y creamos un nuevo proyecto. En la pestaña Board Selector elegimos nuestra placa STM32F411E-DISCO.



A través de este software se pueden activar y desactivar los periféricos y los middlewares disponibles en el microcontrolador STM32F411. Además se pueden asociar los periféricos y funciones a los pines, o asignar funciones alternativas a un pin tales como: GPIO de salida, entrada, de interrupción, analógico, de PWM, etc.

Antes de configurar nada del microcontrolador vamos a configurar el programa para que nos genere el código con la estructura correcta. Para ellos entraremos en Project Settings, pondremos un nombre a nuestro proyecto en Project Name, por ejemplo Toggle Led. En Toolchain/IDE seleccionaremos SW4STM32 y desactivamos el Generate Under Root.

Bajo la pestaña Code Generator seleccionamos Copy only the necessary library files, Generate peripheral initialization as a pair of ‘.c/.h’, Keep user code when re-generating y Delete previously generated files when not re-generated. Aceptamos la configuración.

Ahora nos fijaremos en el pin PD12, que está asociado al led verde. Comprobamos que está en modo GPIO_Output. Y ahora simplemente confiamos que el resto de configuraciones por defecto son correctas.

Generamos el código pulsando sobre Project -> Generate Code. El programa comenzará a generar todo el código y al finalizar, en el cuadro emergente pulsaremos sobre abrir proyecto. Esto nos debe abrir e incluir el proyecto en SW4STM32 (Eclipse).

Podemos ver como tenemos una estructura de directorios y ficheros que nos ha generado CubeMX con todos los drivers y librerias necesarias para nuestro sencillo proyecto. Si abrimos el main.c podemos ver que hay muchas líneas que dicen USER CODE BEGIN/END.



Es muy importante que todo el código que escribamos lo hagamos centro del bloque BEGIN/END. De lo contrario, cuando volvamos a generar código CubeMX lo sobreescribirá y no lo conservará.

En la inicialización vemos que se hace la llamada a MX_GPIO_Init(), con eclipse si mantenemos pulsado la tecla Ctrl mientras hacemos click sobre las función, nos abrirá su definición. Y la leemos un poco podemos ver una sección donde se define la funcionalidad del LD4_Pin asociado al puerto GPIOD y pin GPIO_PIN_12 que en nuestro caso es el GPIO asociado al Led Verde.

Si ahora accedemos a la definición de HAL_GPIO_Init() nos abrirá el fichero stm32f4xx_hal_gpio.c donde podemos ver todas las funciones de la HAL que nos ha generado CubeMX, entre ellas las de Read, Write y Toggle de un GPIO.

En nuestro caso, dentro del while(1) del main() haremos uso de HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_12) para hacer parpadear el led. Para que podamos visualizarlo tendremos que poner un HAL_Delay(500).

Solo nos falta compilar, y debuguear en Ac6 STM32 C/C++ Application. Y con eso podremos ver parpadear nuestro led verde cada 0.5 segundos en nuestra plataforma de desarrollo.

The Twelve of B105: B105 Radar


Termina febrero y eso significa una nueva entrega de…


Esta vez nos hemos centrado en la tecnología radar, con la que llevamos ya varios años trabajando. En la actualidad, dentro del proyecto All-in-One, hemos desarrollado varios prototipos de sensores de bajo coste basados en radar.

Nuestro primer prototipo fue la placa RALPH, que nos permitió validar el diseño y desarrollar el grueso del software de procesado para la detección de la velocidad de los vehículos y su conteo. Incluso tuvimos estudiantes que se atrevieron a meterle mano a esta plataforma y mejorar algunos aspectos de la misma.

En una segunda aproximación, se llevó a cabo un esfuerzo importante para optimizar RALPH al máximo en tamaño, coste y utilización de recursos. Así fue como vio la luz ISHTAR, nuestro nodo sensor radar que, por cierto, utiliza YetiOS como soporte para todo el software. Esta plataforma ha sido probada y validada múltiples veces en entornos reales.




Nuevamente nos despedimos con la esperanza de que nuestros twelve os entusiasmen tanto como a nosotros, y que os permitan conocer mejor todo lo que hacemos por si os interesa uniros y participar de ello. Pincha aquí si quieres ver otros meses.

Si encuentras interesante toda esta información, no dudes en seguirnos en las redes sociales para mantenerte informado.

¡Hasta el mes que viene!

Concedidos todos los Trabajos Fin de Titulación

sold out stamp

Como siempre en el B105 apostamos fuerte por la docencia de calidad. Este año, una vez más, habéis confiado en nosotros y hemos cubierto TODAS las plazas de Trabajo Fin de Titulación ofertadas. Esperamos que cumpláis vuestras expectativas y recordad “Research to learn, learn to teach, teach to push society forward”.

Este curso somos:

Alumno – Tutor

Victor Garvin – Franscisco Tirado
Rosa Pita – Roberto Rodríguez
Óscar Iglesias – Ramiro Utrilla
Jaime Soler – José Martín
Javier Pomeda – Roberto Rodríguez
Javier González – Guillermo Jara
Iván Duque – Alvaro Araujo
Hector Carretero – Francisco Tirado
Carlos del Valle – Guillermo Jara
Ainhoa Seisdedos – Francisco Tirado
Agustín Riscos – Alba Rozas
Adrián Sánchez – Roberto Rodríguez
Ildefonso Áspera – Francisco Tirado/Roberto Rodríguez
David Gil – Alba Rozas
Raquel García – Guillermo Jara
Sezgin Ibramov – José Martín
Denica Dimitrova – Guillermo Jara
Yanqing Wang – Ramiro Utrilla

Alda Martín (Cátedra BQ) – Alvaro Araujo/Ramiro Utrilla
Guillermo Ojeda – Alvaro Araujo
Fernando Martínez – Alvaro Araujo
Jose Antonio Moral – Alvaro Araujo
Agoney Moreno (Cátedra Kairos) – Octavio Nieto-Taladriz

Gracias a todos por vuestro esfuerzo!




B105 Radar Sensor Developments: Software

Radar Interface


The radar platform developed in B105 Electronic Systems Lab contains a microcontroller which process the I and Q signals adapted from the radar transceiver in order to obtain targets information -speed and distance-. The microcontroller used is a low-power STM32L496 that has a DSP module and enough RAM to perform processing tasks. It runs at 48 MHz and has low-power mode, which allows using our platform in battery-powered Wireless Sensor Networks applications.

The software developed in the microcontroller uses the YetiOS operating system which has also been developed in B105 Electronic Systems Lab and is based on well-known FreeRTOS. The architecture of the radar processing module is composed by two tasks:

  • Acquisition and Generation Task. This task is responsible of taking samples from the ADC and generating signals using the DAC synchronously. Both acquisition and generation is done using DMA, so other tasks -such as processing one- could run while taking samples.
  • Processing Task. This task provides the processed information -speed and distance of targets- to the final user. The acquired signal is filtered so the information in undesired frequency bands is eliminated. Besides, a Fast Fourier Transform (FFT) is performed in order to obtain the signals in the frequency domain. Then an OS-CFAR algorithm is applied to select the frequency peaks corresponding to targets, and the targets are selected based on signal levels and SNR ratio.

We have tested the complete radar system in real scenarios and we can process each 128 samples signal in 15 ms. That means that our radar sensor provides distance and speed information with a rate higher to 60 samples per second.

Finally, we have developed an user interface which allows us testing different configuration and the behaviour of the radar sensor on different scenarios.


Radar SW

B105 Radar Sensor Developments: Hardware



Low-cost radar transceivers such as RFbeam ones allows using radar sensors in several applications where cost is an important constraint. However they need a hardware platform to work properly. Therefore, in B105 Electronic Systems Lab we have designed and implemented a hardware platform that allows obtaining using radar sensors in Doppler operating mode and FMCW operating mode.

The platform developed is low-sized and resource-constraint which allows using it in Wireless Sensor Networks applications in battery powered nodes. The hardware modules of the designed system are described below:

  • Power Source. Probably one of the most importan parts of the system as it must provide power to the radar transceiver and to the analog adaptation modules. The power source must provide 12 V, 5 V and 3.3 V for proper radar operation, and these sources must be highly noiseless to enchance radar performance.
  • Radar Transceiver. The main component of the radar sensor is the transceiver which sends and receive radar signals. K-LC5 and K-LC6 radar transceivers from RFbeam may be used, providing I and Q IF signals, and a VCO pin for FMCW operation.
  • Signal Adaptation Module. Signal adaptation is necessary to process radar I and Q signals and obtain information from them. An amplification stage, a low-pass filter and a high-pass filter are used in this module. Besides, a single-ended to differential stage is also used to improve signal acquisition.
  • Signal Acquisition. An ADC is used to digitalize the analog signals so they can be processed. The ADC used can be sigma-delta or SAR, with the higher resolution possible (12 to 16 bits), and with speeds from 10 KHz to 1 MHz. In our platform, the acquisition is done by the main microcontroller.
  • Signal Generation.  A DAC is used to generate the signals to modulate the radar transceiver through its VCO pin. Besides, an adaptation stage is implemented to provide adequated modulation signals to the radar transceivers. The DAC used in our platform is integrated in the main microcontroller.
  • Processing Unit. A microcontroller is needed to process the acquired signals and obtain information from them. In our design a low-power STM32L496 microcontroller is used.

Radar HW


B105 Radar Sensor Developments



Radar technology is a well-known field used since 1940s. This technology has been traditionally applied in military and aerospace fields while it has not been highly exploited in civil applications. However, in the last years, radar transceivers cost-reduction and miniaturization have allowed its application in other fields such as traffic and vehicular safety.

These low-cost radar sensors uses the Doppler effect to obtain information about obstacles or targets in its range. The radar transmits a signal and the frequency shift of the returned signal provides the velocity of the moving targets. There are two main operating modes for these radar sensors:

  • Unmodulated Doppler radar. This operating mode is the most commonly used. The hardware and processing software needed is quite simple which allows using these sensors in size-constraint and resource-contraint devices. However, they only provide velocity information of moving objects in its range. That means that static objects are missed, the distance of the objects cannot be obtained, and two objects moving at the same velocity will be detected as one.
  • Frequency Modulated Continuous Wave (FMCW) radar. This operating mode is used to obtain the distance of static and moving objects. The radar signal is frequency modulated -usually with a frequency ramp- to allow obtaining distances and velocities from the returning signal frequency shift. Thereby, it is necessary to generate a signal to realize the frequency modulation which increases the hardware complexity. Besides, the software processing is harder as there are much more information to process and there are more noise sources from unwanted environment targets.

In B105 Electronic Systems Lab we have developed a full radar system that can operate in both modes and includes all the hardware and the software necessary. This radar system is being used for traffic safety and traffic monitoring applications in several research projects.