S15: Triclops: Smart RC Car - Revision history

146 user5: /* Conclusion */

2015-05-25T21:06:19Z

‎Conclusion

146 user5 at 20:59, 25 May 2015

2015-05-25T20:59:35Z

146 user5: /* Implementation */

2015-05-25T08:16:55Z

‎Implementation

146 user5: /* Implementation */

2015-05-25T08:16:41Z

‎Implementation

146 user5: /* Implementation */

2015-05-25T08:16:19Z

‎Implementation

146 user5: /* PWM Motor and Servo */

2015-05-25T08:16:05Z

‎PWM Motor and Servo

146 user5: /* Proximity Sensors */

2015-05-25T08:15:13Z

‎Proximity Sensors

146 user5: /* Wireless */

2015-05-25T08:14:26Z

‎Wireless

146 user5 at 07:59, 25 May 2015

2015-05-25T07:59:23Z

146 user5: /* Wireless */

2015-05-25T07:58:09Z

‎Wireless

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 == Conclusion ==
-Conclude your project here.  You can recap your testing and problems.  You should address the "so what" part here to indicate what you ultimately learnt from this project.  How has this project increased your knowledge?
+The RC car provided us an opportunity to learn the different topics that were covered in the CMPE 146 Real Time Embedded Systems course. This project was an indicator for us engineering that it is not just enough to have a theoretical knowledge of the concepts. Applying the concepts learned in real life applications can help solidify the concepts for a longer retention of the topics. There were a lot of problems that the three of the group members faces at each step of the project. But no matter what the issue was, rather than replacing a part, we strived to figure out the problem with the device and find a way to make it work to our needs. We look forward to keep working on the car as a side hobby to improve its functionalities and maybe implement more features to enhance its performance
 === Project Video ===

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 == Abstract ==
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 == Design & Implementation ==
-The design section can go over your hardware and software design.  Organize this section using sub-sections that go over your design and implementation.
 === Hardware Design ===
 [[File:S15_146_IMG_OVERALL_WIRING.png|center|frame]]
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 === Hardware Interface ===
 *Motor and Servo
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 === Software Design ===
-Show your software design.  For example, if you are designing an MP3 Player, show the tasks that you are using, and what they are doing at a high level.  Do not show the details of the code.  For example, do not show exact code, but you may show psuedocode and fragments of code.  Keep in mind that you are showing DESIGN of your software, not the inner workings of it.
 ====Tasks====

← Older revision		Revision as of 08:16, 25 May 2015
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	The image shown to the left is the basic logic used for the car's brain. The sensors, compass and GPS all send directions to the PWM. This feature was achieved using shared queues. This allowed the PWM to get the required information to navigate efficiently. So if it received a left signal from the direction queue, it turned left. If it received a signal from the front sensor it would stop. etc. The LIPO battery pack of the RC car provided power to the motors and this same battery was used to power the whole car and it devices. A 3.3V supply from the SJSU One board was used to power the Servo. The picture on the right below is an image of the motor and servo on the car.		The image shown to the left is the basic logic used for the car's brain. The sensors, compass and GPS all send directions to the PWM. This feature was achieved using shared queues. This allowed the PWM to get the required information to navigate efficiently. So if it received a left signal from the direction queue, it turned left. If it received a signal from the front sensor it would stop. etc. The LIPO battery pack of the RC car provided power to the motors and this same battery was used to power the whole car and it devices. A 3.3V supply from the SJSU One board was used to power the Servo. The picture on the right below is an image of the motor and servo on the car.
	[[File:S15_146_G6_PWM_Image.JPG\|right\|border\|400px]]		[[File:S15_146_G6_PWM_Image.JPG\|right\|border\|400px]]
		+

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 [[File:S15_146_G1_PWM_Logic.png|left|border|400px]]
-===Implementation===
+====Implementation====
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+.
 === GPS ===

← Older revision		Revision as of 08:16, 25 May 2015
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	[[File:S15_146_G1_PWM_Logic.png\|left\|border\|400px]]		[[File:S15_146_G1_PWM_Logic.png\|left\|border\|400px]]

−	==Implementation==	+	===Implementation===

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 **Wireless Task-This task is used for the car to be able to stopped from another SJSU One board.
-==PWM Motor and Servo==
+===PWM Motor and Servo===
 [[File:S15 146 G6 PWM Waveform.jpg|right|border|400px]]
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 In our RC car both the Motor that powers the wheels and servo that turns the wheels, require pwm signals to function. Our car had a Brushless motor, which worked in a three phase current system. But fortunately, the motor was accompanied with  a ESC(Electronic Speed Controller) which took care of the the motor power control. But in order to send signals to the motor, we had to send signals to the ESC which forwarded the signal to the motor in a way that the motor required. The Servo was a standard servo, which also worked on the concept of pwm. If the signal for the servo or motor was held high for a certain time period, then it would perform the following actions; 1.5 ms was the mid point or stop, 1 ms was left or back, and 2 ms was right or full speed. Since our car was built to go pretty fast (30-40 mph at max), we barely used the car to its full potential to avoid chasing after the car at those speeds. The image to the right shows the the waveform of the pwm from the SJSU One board sending a 6%duty cycle, which is what we need at a 50 hz frequency to emulate a stop signal.
 [[File:S15_146_G1_PWM_Logic.png|left|border|400px]]
 ==Implementation==

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 Since we had an issue inconsistent supply voltage we '''implemented an Resistor-Capacitor circuit to the voltage supply of each sensor''' to compensate for voltage spikes.
-[[File:S15_146_G6_sensorSchematic.jpg|200px]]
+[[File:S15_146_G6_sensorSchematic.jpg|center|200px]]
 ===Wireless===

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 ===Wireless===
-The wireless capability on this program allowed us to stop or start the car from a remote location rather than chase after the car. We used the functionalities that were already on the board made by Preet. THe only thing we need to do was to change a bit in the sys_config.h which allowed one board to send data to another board via the terminal. So, for instance, if a host wanted to send a command to the client all they would have to do is type "wireless stream <addr> <msg>, where address is the address of the client device and msg is the command to send to the client board.The schematic below shows a overview of how the wireless devices are set up.
+The wireless capability on this program allowed us to stop or start the car from a remote location rather than chase after the car. We used the functionalities that were already on the board made by Preet. THe only thing we need to do was to change a bit in the sys_config.h which allowed one board to send data to another board via the terminal. So, for instance, if a host wanted to send a command to the client all they would have to do is type "wireless stream <addr> <msg>, where address is the address of the client device and msg is the command to send to the client board.THe user has additional options to customize their wireless signals in the same config file.
 == Testing & Technical Challenges ==

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 **  Quality of technical challenges and solutions adopted.
 </font>
 == Abstract ==
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-===Implementation===
+==Implementation==
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-== GPS ==
+=== GPS ===
 [[File:S15 146 G6 IMG GPS MODULE.png|left|border|300px]]
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-=== Implementation ===
+==== Implementation ====
 The GPS outputs data in a format known as the NMEA sentence. There are a few different forms this sentence can take, we used a form called GPGLL. This form contains much less information than other sentences; however, it was quite sufficient for our needs. This form contains the longitude, latitude, UTC time, status of the GPS, and a checksum. In order to use this information, we parsed the sentence for only the longitude and latitude information. We then turned this information into radians to use for finding the heading.
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 .</syntaxhighlight>
-==Magnetometer==
+===Magnetometer===
 [[File:S15_146_G6_magnetometer.jpg‎|right|border|200px]]
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 Data is read into six separate registers. There are two registers for each X, Y, and Z readings. For our purposes the Z reading could be omitted because the magnetometer was positioned in a way where the XY plane is parallel to the Earth. The data for each reading is 16-bits wide; however, it is split into two separate 8-bit registers and is stored as a 2's compliment signed integer. In order to read the entire measurement, both registers must be read. The data obtained from these registers are raw magnetic readings and must be converted to a usable heading in degree format.
-===Implementation===
+====Implementation====
 Converting the raw magnetic data from the magnetometer was handled using a simple arctan function found in the <cmath> library. However, in order to use the arctan function, the data must first be converted into float values. The code for the conversion can be found below.
 <syntaxhighlight lang="cpp">
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 In order to compensate for our location on Earth and the way the Earth tilts, a declination angle must be used to compensate the final reading. This declination angle can be found at http://www.ngdc.noaa.gov/geomag-web/. The final value must also be adjust to ensure that it falls within the 0-2π range. In order to make the result more readable to us, the value was converted back into degrees.
-==Proximity Sensors==
+===Proximity Sensors===
 [[File:S15_146_G6_sonarfront.jpg‎|left|frame|MB1010
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+.
-===Implementation===
+====Implementation====
 The first method we used to try to interface with the sensor was through a UART port on our SJSUOne board. However, this proved to be troublesome as the sensor does not follow the RS232 standard and inverts all of its signals. In order to decode the signal we would have had to use a voltage inverter. To get around this, we decided to use the analog voltage output. The sensor will hold a base voltage while it sends out a pulse. As time goes on, the voltage will slowly begin to increase in 512 equal levels. The time it takes for the pulse to return to the sensor determines the final voltage it outputs over the AN pin. This results in a signal of (Vcc/512) per inch. There was a lot of issued with cross talk  between the three sensors, we made sure to bend the front bumper so we would not deal with one sensor messing up the other. Along with this we also implemented an trigger to the Sonar sensor so that we could control when to send the sound wave. These two methods allowed the sensors to get reading one at a time and eliminate crosstalk.
 Since we had an issue inconsistent supply voltage we '''implemented an Resistor-Capacitor circuit to the voltage supply of each sensor''' to compensate for voltage spikes.
@@ Line 399: / Line 397: @@
 [[File:S15_146_G6_sensorSchematic.jpg|200px]]
-==Wireless==
+===Wireless===
 The wireless capability on this program allowed us to stop or start the car from a remote location rather than chase after the car. We used the functionalities that were already on the board made by Preet. THe only thing we need to do was to change a bit in the sys_config.h which allowed one board to send data to another board via the terminal. So, for instance, if a host wanted to send a command to the client all they would have to do is type "wireless stream <addr> <msg>, where address is the address of the client device and msg is the command to send to the client board.The schematic below shows a overview of how the wireless devices are set up.