Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: logicman on April 29, 2008, 03:12:17 AM

Title: Flexi / interval timer
Post by: logicman on April 29, 2008, 03:12:17 AM
Hi everyone.

Firstly, I'm totally new to robot building and would appreciate any help given, so take it easy on me if i sound a bit noobish.  :)

I have an assignment to do where i have to build a robot, which is autonomous, that has to complete a few tasks and i am trying to keep it as basic as possible.

So here is what i want the robot to do:

1. From rest, the robot has to travel forward, say 5m.
2. At this point the robot can either come to a complete stop or just start reversing back (3m) and the go forward again (1m)
3. Finally, the robot must reverse all the way back to its starting position.

Now, there is a lot more to do than what is said above, but this is the main part.

I'm looking at using timers to do this for me. So I'm looking at the product below:

http://jaycar.com.au/productView.asp?ID=KA1732&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=335 (http://jaycar.com.au/productView.asp?ID=KA1732&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=335) 


I want to know:

- Is this product is capable of timing the robot and then reversing the polarities of the motors at the specified times to make the robot reverse and can it cut power to motors.
- How would i go about doing something like this ie. do the IC chips have to be programmed?
- Is there anything else that i could use that is not too complex and relatively cheap?

Thanks again for any help anyone can give.
Title: Re: Flexi / interval timer
Post by: benji on May 03, 2008, 04:44:45 PM
Quote
2. At this point the robot can either come to a complete stop or just start reversing back (3m) and the go forward again (1m)
based on what? stopping or reversing based on what ? sensors?

Quote
3. Finally, the robot must reverse all the way back to its starting position.
EASY, just save the way you walked and then loaded it again .. reversed

Quote
I'm looking at using timers to do this for me
just use a cheap microcontroller, it has timers enough for that

Quote
- Is this product is capable of timing the robot and then reversing the polarities of the motors at the specified times to make the robot reverse and can it cut power to motors.
a microcontroller CAN
,,are yo using defferential drive?

Quote
- How would i go about doing something like this ie. do the IC chips have to be programmed?
yuppp

Quote
- Is there anything else that i could use that is not too complex and relatively cheap?
for this task you should use a microcontroller (AVR , PIC, 8051)
and yea they are cheap enough



Title: Re: Flexi / interval timer
Post by: Admin on May 04, 2008, 07:01:49 AM
Does it need to be exact distances, or just do these general motions based on a timer?

That timer can time things, but thats all it really can do - it can't drive motors for example. As benji suggested, you should just do a programmable microcontroller. There are many you can buy:
http://www.societyofrobots.com/robot_faq.shtml#best_microcontroller
http://www.societyofrobots.com/robot_parts_list_microcontrollers.shtml

And you can make your own:
http://www.societyofrobots.com/step_by_step_robot.shtml
Title: Re: Flexi / interval timer
Post by: superchiku on May 04, 2008, 07:41:18 AM
bengi by sayinf this
Quote
3. Finally, the robot must reverse all the way back to its starting position.

EASY, just save the way you walked and then loaded it again .. reversed


what do u exactly mean
Title: Re: Flexi / interval timer
Post by: izua on May 04, 2008, 08:50:39 AM
odometry (http://www.societyofrobots.com/sensors_encoder.shtml)
Title: Re: Flexi / interval timer
Post by: benji on May 04, 2008, 09:33:07 AM
Quote
bengi by sayinf this
Quote
3. Finally, the robot must reverse all the way back to its starting position.

EASY, just save the way you walked and then loaded it again .. reversed

you robot is walking, just find someway to save how much you are walking,,how many cms , including where u are making turns,
how many angles
then do it again reversed

lets say we save things this way

array=[50 , 60 , 80, -45 , 13 ];

this means that the robot walked 50 cms forward
then it turned 60 degrees
then it walked 80cms
then turned -45 degrees
then walked 13cms

its some sort of coding your movements , u can do it the way you like

now if your question is hoe did i get this values?
it depends on your robot
if it has wheels then an encoder would do
a walking bot? u simply count how many steps its walkin

this is what izua just briefed in one word
Title: Re: Flexi / interval timer
Post by: superchiku on May 04, 2008, 10:17:30 AM
i didnt meant that i know abt the encoder i thought ur talking abt some kinda mapping..