Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: sean22 on March 09, 2009, 06:06:44 PM

Title: Which sensor is the right one
Post by: sean22 on March 09, 2009, 06:06:44 PM

SFE sells different kinds of sharp IR senors which is the correct one for the 50 dollar robot

1. https://www.sparkfun.com/commerce/product_info.php?products_id=242 (https://www.sparkfun.com/commerce/product_info.php?products_id=242)

2. https://www.sparkfun.com/commerce/product_info.php?products_id=8958 (https://www.sparkfun.com/commerce/product_info.php?products_id=8958)

3. https://www.sparkfun.com/commerce/product_info.php?products_id=8959 (https://www.sparkfun.com/commerce/product_info.php?products_id=8959)

Thanks

Title: Re: Which sensor is the right one
Post by: Razor Concepts on March 09, 2009, 06:07:42 PM

You can use either one, but the best one (larged range) is this one:
https://www.sparkfun.com/commerce/product_info.php?products_id=8958 (https://www.sparkfun.com/commerce/product_info.php?products_id=8958)

Don't forget to buy the cable for it, too.

Title: Re: Which sensor is the right one
Post by: pomprocker on March 09, 2009, 06:14:13 PM

Depends what kind of distance you want to sense. Remember to offset the minimum distance the sensor can not see by mounting the sensor inward on your robot chassis, not right on the edge.

Required reading:
http://www.acroname.com/robotics/info/articles/sharp/sharp.html (http://www.acroname.com/robotics/info/articles/sharp/sharp.html)

Title: Re: Which sensor is the right one
Post by: paulstreats on March 09, 2009, 06:22:15 PM

pomprocker posted while i was typing, but since ive typed it aswell...

razor is right, but it really depends on what you want...

The $50 robot can use any of them

the 1st one has a range of 10cm to 80cm so your robot is effectively blind between 0cm and 10cm range

the 2nd one has a larger blind spot 0cm to 15cm but after 15cm it can see as far as 150cm

the 3rd one is only blind for the first 3cm but it can only see 30cm maximum

What would be most useful for what you want it to do? and what maximum or minimum distance constraints do you want to work with. (the edge finding algorythm will work with any of them).

You might be tempted to just get the one with the largest range but the pre made edge finding function might make it concentrate on walls rather than following you around in a smallish room. (you can of course enhance the algorithm yourself).

Title: Re: Which sensor is the right one
Post by: sean22 on March 09, 2009, 06:44:18 PM

i think the smallest range might be best for me because then it would get closer to objects before it moves which would be more interesting than it staying in the middle of the room now if i get this one with the small range would code changes be required.

Title: Re: Which sensor is the right one
Post by: paulstreats on March 10, 2009, 08:15:18 AM

If you are using the edge finding code (the sharpIR upgrade code) then no you wont need any changes.

Just remember that it cant see targets beyond 30 cm though. This being said, what is the behaviour of the $50 robot is there arent any targets? does it go looking for them or does it just sit there waiting for something to come into range

Title: Re: Which sensor is the right one
Post by: sean22 on March 10, 2009, 01:57:42 PM

it move around avoiding abojects