Mega Project: Robotic Land Mine Detector

[glenjoy]

I think it will be better if you will show the flowchart first, then you illustrate the path of the robot, also, tell us what you really want to happen on your robot, be consistent.

 

[purifier]

I need some more time for the flowchart. And i've been consistent from the beginning. It is only that i'm unable to explain it clearly because of my lack of knowledge in the field of robotics. So please bear with me...

 

[nafaiz]

45 days are very short period. i seriously tell u that if u dont work hard and fast enough, the 45 days will not be enough.

so, u can only have i bot. means ur opponents also can have only one bot. to win, u'll the fastest bot. to have the fastest bot is by having high speed dc motors or good programming. it's better if u can have both. but remember, higher speed dc motors will have less torque. this means ur robot shouldn't be heavy.

for good programming, i agree with glenjoy. write the flow chart and post it here. members here may help by giving better ideas.

 

[purifier]

I'll do that today. Should i go for a dc motor or a stepper motor? I heard that using a stepper motor, we can control the movement of the robot very precisely so as to make it stop exactly on the pit. What should i go for?

Added after 16 minutes:

Also, my other three team members who are from the mechanical background say that they won't be using actual wheels for the robot because the wheels might get stuck in a pit which is 5x5x5 cm. And if it gets stuck there is no way of getting the robot out... So they're planning to use the track system. Four wheels + Four motors for the wheels and a chain around the motors to complete the track movement... But i think there would be some inconsistency... What do you say?

 

[nafaiz]

I'll do that today. Should i go for a dc motor or a stepper motor? I heard that using a stepper motor, we can control the movement of the robot very precisely so as to make it stop exactly on the pit. What should i go for?

u r absolutely correct. use the stepper motor.

Added after 16 minutes:

Also, my other three team members who are from the mechanical background say that they won't be using actual wheels for the robot because the wheels might get stuck in a pit which is 5x5x5 cm. And if it gets stuck there is no way of getting the robot out... So they're planning to use the track system. Four wheels + Four motors for the wheels and a chain around the motors to complete the track movement... But i think there would be some inconsistency... What do you say?

it's okay to use 4 motors. it's also okay to use just 2 in front. for the back wheel u may also use dummy wheels as the front wheels will be ur robot controller. whatever it is try it on ur game field and try to improve things later on.

 

[purifier]

I thought i should develop the code in C because there is no time for me to learn assembly... So, i was told to use what is called as a cross compiler. And i could get my hands on KEIL.

Are there any websites out there which tell me how to program a microcontroller in C for practical application. For instance, i put a sensor. Once it detects a white line, it'll give a signal. That signal has to be interpreted and a particular motor has to be run. Now, how do code the same in C for the 8051 Microcontroller. Please help...

 

[glenjoy]

I thought i should develop the code in C because there is no time for me to learn assembly... So, i was told to use what is called as a cross compiler. And i could get my hands on ke*il.

Are there any websites out there which tell me how to program a microcontroller in C for practical application. For instance, i put a sensor. Once it detects a white line, it'll give a signal. That signal has to be interpreted and a particular motor has to be run. Now, how do code the same in C for the 8051 Microcontroller. Please help...

Hi,

Search for the book Embedded C.

For example White = 0 and other colors = 1, and you want to use Pin 0 of Port 1

P1.0 = 1; // set Port1.0 as input
while(P1.0);
if(P1.0 == 0)
{
//White line detected
}
else
{
//Other colors
}

 

[purifier]

Thank you very much for the advice... Is the book available in eBook format? I mean doi have to buythe book or is it possible for me to download it? Because the other day, i just went to a nearby book store but couldn't find any such books... Also, once i write a code in C how do i put it into a microconttroller? Do i need a cross compiler? Because Keil was not available freely so are there any free cross compilers out there... I'm really sorry if i'm asking some obvious questions. These obvious questions to a beginner are the most complex ones. So please bear with me...

 

[purifier]

My time is running out... I could get hold of the book on Embedded C but it has nothing much about Microcontroller programming in C. Someone please help me...

Added after 50 minutes:

Can someone tell me how to do this in keil...
1. Write a simple C program to read an input check some conditions and then send an output.
2. Convert it into the format that is required for the 8051.
3. What extra things are required to put that into the 8051.
4. Simple circuit connection of 8051 to acheive the above purpose.

Also, is there any site that provides a simple program for stepper motor control through C that i can implement in my program? Please help..

 

[adedia]

try here
_http://www.learn-c.com/
or here
_http://www.commlinx.com.au/microcontroller.htm
and
_http://www.commlinx.com.au/microcontroller.htm

it has a lot

 

[purifier]

Thanks a lot for the links. Those are great though i saw the first one earlier. Can someone tell me how to implement the project listed in **broken link removed** without that serial port connection? Is it ok if i simply remove those connections?

 

[gerryseq]

From the schematic ,i would say that the serial port is being used to control the speed and direction of the stepper....The microcontroller,that is the 89c2051 is just decoding the serial commands and delivering appropriate step signals to the stepper.

You could avoid using the serial connections,but controlling would have to find a way to control direction and speed...maybe with pushbuttons for direction and a potentiometer for speed.

The uln2003 is just a motor driver,so that the motor doesnt draw too much current from the micro

**ice**
**broken link removed**

 

[purifier]

Thanks a lot. I've decided to use a Servo Motor instead of a stepper motor. Can someone tell me how to control a servo motor using 8051 in C? Please help... I don't have any idea about Servos but i know that they have more precision control over other motors.

 

[fat_mac]

i juz bought a servo motor too, so far to my knowledge, you first have to determine the Pulse Width Modulation (PWM) of the servo, it's to determine the length of the pulse you would need to send to turn the servo by a certain degree. follow the link to get more information. hope it's of help.

**broken link removed**

hope you dun mind me borrowing your thread. Hopefully the experts here can help me with my project too when they have read your thread. please and thanks.

this is the link to my thread, its another robotics project

 

[purifier]

Thank you very much. Hope someone could answer even these qs...
1. I see everyone writing that you can control a servo but are they used for a robot's movement?

2. If so, inorder to move it in the opposite direction, is it enough if i send a negative pulse? And how do i do that using 8051? I was told that you can directly send a pulse from 8051 without the need for 555 IC. Did i hear it correctly? Please help...

 

[purifier]

Someone please help... Time is running out...

None of the metal detectors, obstacle sensors, white line detector i found are working. Does anyone know of some working circuits. Please... I desperately need help at this point. I can't give up at this stage... Please help...

 

[glenjoy]

Thank you very much. Hope someone could answer even these qs...
1. I see everyone writing that you can control a servo but are they used for a robot's movement?

2. If so, inorder to move it in the opposite direction, is it enough if i send a negative pulse? And how do i do that using 8051? I was told that you can directly send a pulse from 8051 without the need for 555 IC. Did i hear it correctly? Please help...

1. Servo motors are usually used in robotics movement, but for very accurate pick and place robotics, they use pneumatics.

2. So that you can make the servo motor turn into the opposite direction, try to modify your PWM configurations. In your PWM signal, you will have somewhat a center PWM signal that will make the servo motor not turning. If you try to increase or decrease the pulse widths, the motor shaft will turn but the direction is PWM dependent.

 

[fat_mac]

i tried checking for the PWM of servo (Sanwa SRM-102) using a function generator but the servo only rotates anti-clockwise even though i vary the frequency between 400 Hz and 1.6KHz. can someone pls teach me how to do it correctly (maybe i'm setting the function gen incorrectly). thanks.

 

[purifier]

Can someone suggest me some algorithms to achieve the desired movement? I'll ask the robot to follow a path but when it encounters an obstacle, what changes are to be implemented so that it still covers all the pits... Please help... I'm stuck with the planning phase now....

 

[nafaiz]

i think ur idea is great, but for safety use 2 or more sensors for detecting straight line. as i mentioned earlier, the movement of the robot should be like in diagram 2.

I'll implement that change...

can i know how long u still have before the game starts.

Exactly 45 days from now, i'll have to submit it...

for ur information, assembling the robot takes more time than programming it. so start assembling the robot now. divide groups by 2 for game field and 2 for assembling. game field wont take long, so later the other two may join u assembling the robot.

I'll take your advice and start on the board right away...

by the way, how many robots u can have or how much is the weight restrictions for all robots?

I can have only one bot... I don't think there is any weight restriction but we do have a size restriction 20x30xunlimted height...

Hie,
remember me? i thought the game should have started last year....it's already been a year+.

Regards,
Nafaiz