This week was a pretty busy week with less of research work and more of documentation. This week was spent on data pooling from the network. This activity was carried out to measure performance of the network and the motes in different modes of operation.
Micaz motes are programmed into distinct groups of operation. The first group of motes are programmed to measure ambient temperature, second group to measure vibration and sound intensity of transformers and circuit breakers, third group programmed to measure the surface temperature of equipments and the fourth group of motes to detect SF6 gas leaks.
The motes can also be classified based on the frequency of packet forwarding. The high forwarding or periodic motes are the ones who transmit data packets every 15 minutes. The low forwarding or level crossing motes are the ones who transmit packets only if any parameter (i.e. temperature or vibrations) increase above a certain preset threshold.
The data pooling activity involved recording difference or drop in battery voltages of motes depending on their location or proximity to the base station and a comparison of voltage drops in periodic Vs Level crossing motes. As expected the periodic motes will have a higher voltage drop as compared to the level crossing one's because of more number of packet transmissions. The activity also involved measuring the solar irradiation in the region so as to speculate the viability of "heliomotes" which convert solar energy into usable electrical energy. The final activity involved a comparative study of the average number of packets transmitted by motes in each of the region (region depends on proximity to the base station). The motes which were at a greater distance from the base station were seen to transmit slightly lesser number of packets than the ones near to the base station. The reason is probably because packets have to traverse greater distance over multiple hops. Even though the Xmesh protocol exhibits reliability of transmission, some packet losses are involved over multiple hops.
Friday, May 28, 2010
Wednesday, May 26, 2010
My Videos
Texas Instruments Launchpad - Getting Started with the msp430 launchpad
A sensor network in 90 seconds
_______________________________________________________
Wireless Sensor Networks: Technology and Applications
_______________________________________________________
Wireless Sensor Networks: Technology and Applications
Thursday, May 20, 2010
Advanced Embedded Systems - Semester Project
Hi All,
The semester ends on a good note with a well done semester project. The project was to design a conceptual prototype of an "RFID based personal home automation system." The system is basically designed to control electrical appliances found in homes depending on the RFID tags detected.
The Concept: The basic concept of this system was custom operations of appliances depending on the individual needs of the users using the appliance. For example, Person A living in a home likes the room temperature to be at 75 deg F, likes the room lighting to be dim and would like the home theater system to start as soon as he enters the room. The person A would have an RFID tag with him all the time in simple form such as a key-chain, a smart card or even a removable sticker attached to his apparel. The main door frame of the house is conceptualized to be a RFID tag reader. As soon as person A enters the house, the tag reader reads the unique tag and transfers it to a system (which can be a laptop computer or any custom embedded system). A program running on the laptop will read the RFID reader log-file and send the tag to a mote (Crossbow's mica2 mote) connected to the same laptop using a standard USB cable.
The mote connected to the laptop is the base station which broadcasts the tag-id to all the motes which are conceptualized to be connected to the electrical appliances. The appliances will work in a customary manner according to tag-ids being received by the motes i.e. in this scenario, the mote connected to the air conditioning system will set the thermostat at 75 deg F according to person A's needs. Likewise, every member of the house can carry a tag with the preference level set for every tag.
The setup: Texas Instruments TRF7960 EVM hardware module was used as a tag reader. The features include: Support for ISO 15693 standard, An onboard 13.56 MHz loop antenna and interface, Communication with host software on a Windows based PC through a standard USB interface.
A laptop which runs Windows XP (to run the RFID tag-it software and TinyOS) and has cygwin installed. Cygwin is a software which runs on windows and creates a UNIX like operating system environment. TinyOS is installed on the laptop to program the motes and inject commands into the network.
Crossbow mica2 motes are used to control the appliance. To demonstrate the application, the debugging LED's on the moca2 motes were used as indicator of different tags. One of the motes was connected to the laptop to function as the base station. The base station was programmed with the TOSBase module. The remote motes were prorammed with the SimpleCmd module.
Working: A program (designed using C) runs in the cygwin environment which reads the log file created by the tag-it software. The program searches for the particular unique tag in tha log file. As soon as the tag is detected, it broadcasts it using the "BCastInject" java tool through the base station. Depending on the tag received, the red or the green LED's on each mote turns ON. If the tag is detected the second time (which would mean that the person has exited) the respective LED's toggle.
The future work would involve designing a control system for each appliances to interface the mote so that they can be controlled directly.
The semester ends on a good note with a well done semester project. The project was to design a conceptual prototype of an "RFID based personal home automation system." The system is basically designed to control electrical appliances found in homes depending on the RFID tags detected.
The Concept: The basic concept of this system was custom operations of appliances depending on the individual needs of the users using the appliance. For example, Person A living in a home likes the room temperature to be at 75 deg F, likes the room lighting to be dim and would like the home theater system to start as soon as he enters the room. The person A would have an RFID tag with him all the time in simple form such as a key-chain, a smart card or even a removable sticker attached to his apparel. The main door frame of the house is conceptualized to be a RFID tag reader. As soon as person A enters the house, the tag reader reads the unique tag and transfers it to a system (which can be a laptop computer or any custom embedded system). A program running on the laptop will read the RFID reader log-file and send the tag to a mote (Crossbow's mica2 mote) connected to the same laptop using a standard USB cable.
The mote connected to the laptop is the base station which broadcasts the tag-id to all the motes which are conceptualized to be connected to the electrical appliances. The appliances will work in a customary manner according to tag-ids being received by the motes i.e. in this scenario, the mote connected to the air conditioning system will set the thermostat at 75 deg F according to person A's needs. Likewise, every member of the house can carry a tag with the preference level set for every tag.
The setup: Texas Instruments TRF7960 EVM hardware module was used as a tag reader. The features include: Support for ISO 15693 standard, An onboard 13.56 MHz loop antenna and interface, Communication with host software on a Windows based PC through a standard USB interface.
A laptop which runs Windows XP (to run the RFID tag-it software and TinyOS) and has cygwin installed. Cygwin is a software which runs on windows and creates a UNIX like operating system environment. TinyOS is installed on the laptop to program the motes and inject commands into the network.
Crossbow mica2 motes are used to control the appliance. To demonstrate the application, the debugging LED's on the moca2 motes were used as indicator of different tags. One of the motes was connected to the laptop to function as the base station. The base station was programmed with the TOSBase module. The remote motes were prorammed with the SimpleCmd module.
Working: A program (designed using C) runs in the cygwin environment which reads the log file created by the tag-it software. The program searches for the particular unique tag in tha log file. As soon as the tag is detected, it broadcasts it using the "BCastInject" java tool through the base station. Depending on the tag received, the red or the green LED's on each mote turns ON. If the tag is detected the second time (which would mean that the person has exited) the respective LED's toggle.
The future work would involve designing a control system for each appliances to interface the mote so that they can be controlled directly.
Friday, April 30, 2010
I'm just back from the embedded lab after a whole day of work. The last lab in advanced embedded sounded really simple but is definitely not when it comes to putting it all together.
The challenge: Interface a DC motor to the Renesas M16C micro-controller. The motor speed must be controlled by commands from a computer. So basically I had to write down a code for serial communication between the PC and the microcontroller to use the uC UART. The motor speed was controller by varying the duty cycle of the PWM pulse from 100% to 0. (Status -> Done. This was pretty easy and took me just under 2 hours to do this)
Next we had to design a tachometer to count the speed in rpm of the motor. Initially, we used the very basic VT43N1 LDR (Light dependent resistor) to design the tachometer. The LDR was supposed to detect and send a pulse to the I/O port of the M16C every time a shadow of the rotor wing attached to the motor would fall on it. This method was however not accurate as the micro-controller missed a whole lot of wing rotations. We then shifted focus on the TSOP1156
IR demodulator which would detect IR pulses from an IR LED. Though this approach seemed to work well, it was not feasible as the demodulator would be sensitive only to a pulsed input from the LED and would be sensitive enough to give acceptable results at 56KHz frequency. Generating 56Khz at an amplitude of 1.5v (for the IR LED) did not seem to be a good idea for an embedded system.
Finally, we decided to work back to the basics and used the much simpler IR Transmitter and receiver pair which is basically a LED made from gallium arsenide which emits infrared light at 880nm to be used as a transmitter. I used 3V Vcc with a current limiting resistor to power the IR LED. Just to make sure the LED is emitting IR light, you can check that by observing the LED with you cell phone camera and you can see the IR LED glow!! The IR receiver is an IR photo-transistor operating at 3.5 - 6V with its base powered by the IR light from the transmitter. The anode gives 0v output when IR light is reflected directly on its base. The pair just needs to be close enough to have a good output. (Status --> Done)
The main challenge was programming the MSP430F1122 micro-controller by Texas Instruments. We had to program a custom made platform with the MSP430 using a JTAG port on the board connected to the parallel port of a computer using the IAR embedded workbench. We are working on it now!!! Will post as soon as its done.
Until then, happy debugging.....
The challenge: Interface a DC motor to the Renesas M16C micro-controller. The motor speed must be controlled by commands from a computer. So basically I had to write down a code for serial communication between the PC and the microcontroller to use the uC UART. The motor speed was controller by varying the duty cycle of the PWM pulse from 100% to 0. (Status -> Done. This was pretty easy and took me just under 2 hours to do this)
Next we had to design a tachometer to count the speed in rpm of the motor. Initially, we used the very basic VT43N1 LDR (Light dependent resistor) to design the tachometer. The LDR was supposed to detect and send a pulse to the I/O port of the M16C every time a shadow of the rotor wing attached to the motor would fall on it. This method was however not accurate as the micro-controller missed a whole lot of wing rotations. We then shifted focus on the TSOP1156
IR demodulator which would detect IR pulses from an IR LED. Though this approach seemed to work well, it was not feasible as the demodulator would be sensitive only to a pulsed input from the LED and would be sensitive enough to give acceptable results at 56KHz frequency. Generating 56Khz at an amplitude of 1.5v (for the IR LED) did not seem to be a good idea for an embedded system.Finally, we decided to work back to the basics and used the much simpler IR Transmitter and receiver pair which is basically a LED made from gallium arsenide which emits infrared light at 880nm to be used as a transmitter. I used 3V Vcc with a current limiting resistor to power the IR LED. Just to make sure the LED is emitting IR light, you can check that by observing the LED with you cell phone camera and you can see the IR LED glow!! The IR receiver is an IR photo-transistor operating at 3.5 - 6V with its base powered by the IR light from the transmitter. The anode gives 0v output when IR light is reflected directly on its base. The pair just needs to be close enough to have a good output. (Status --> Done)
The main challenge was programming the MSP430F1122 micro-controller by Texas Instruments. We had to program a custom made platform with the MSP430 using a JTAG port on the board connected to the parallel port of a computer using the IAR embedded workbench. We are working on it now!!! Will post as soon as its done.
Until then, happy debugging.....
Tuesday, April 27, 2010
Something about my Master's thesis
I am presently working on my Master's thesis under the guidance of my advisor, Dr. Nasipuri to design and implement a load balanced and energy aware routing algorithm for large scale wireless sensor networks, typically a mesh network. A setup of wireless motes running Crossbow's XMesh protocol is in place at the TVA Paradise substation in Kentucky, Tennessee.
Crossbow Technology's micaz wireless motes (fig 1) which are equipped with Atmel's ATMega128L processor running at 8Mhz, 2.4GHz Chipcon cc2420 radio, 128KB program memory, 512KB measurement flash and 4KB EEPROM is used as a platform to monitor electrical equipments along with MTS300/310 which is an integrated sensor board that features built in sensors for temperature, light, acoustic signals and also a dual axis accelerometer (MTS310) in addition to a magnetometer (MTS310).
The main objective of this project was preemptive diagnosis of possible failures in transformers, circuit breakers and compressors and monitoring its health at all times. This saves a lot of human effort and the sensors attached to the body of these heavy electrical equipments send periodic data captured by its on-board sensors to a centrally located base station.
Crossbow Technology's XMesh protocol is used for routing this collected data to the base station. The motes are programmed using a specially designed operating system for wireless sensors i.e. the TinyOS. Programming is done using nesC language which is similar to C.
More information can be found from the Crossbow website here: InTech- A real mesh
I had given a presentation on the same in my advanced embedded systems class. Here is the link to it : Presentation on WSN's for substation monitoring
Dexter's lab, is gonna be the name for my tech blog. Inspired from one of my all time favorite cartoon character, DEXTER....the boy genius!!! I really enjoyed the cartoon "Dexter's Lab" on cartoon network as a kid and always dreamed to have an underground lab...( :D ) just the way Dexter had.... so much for childhood dreams.
This is where i will be writing all my experiences as an engineer, about my experiences as a Master's student, about my graduate thesis and about all the geeky stuff that I do or intend to do...
Thanks for reading....
Subscribe to:
Posts (Atom)