what is the best photoreflector to use for a line follower?

[rox2007]

I am building a line follower to compete. I was going to use photoresistors but i read in so many places on the internet that they are really slow in reaction. They are actually slow because i did some tests and thought the same. They mostly suggested infrared emitters but the best is photoreflectors. If anyone has had experiences with line followers please help me.

[paulstreats]

look at products like these

[url]http://www.sparkfun.com/commerce/product_info.php?products_id=246[url]

They are an ir emitter and detector in 1 package, basically the emitter sends out ir light and if it is reflected back from a surface the detector um detects it.

[airman00]

I use the QRB1113 or the QRB1134 in my line follower project ( check member tutorials page)  .

the sensors are available from fairchild

[rox2007]

i'll check those out

[airman00]

may i ask which competition>

[rox2007]

my school (rutgers university-new brunswick) is holding an ieee robotics competition. Line followers and all.

[Admin]

I was going to use photoresistors but i read in so many places on the internet that they are really slow in reaction

I disagree. The slowest of photoresistors have a full swing voltage time of ~100ms. The ones I use take like 20ms between a line and no line. Thats pretty darn fast.

Look at the photoresistor datasheet for proof

Ive made two robots that use photoresistors for line following:
http://www.societyofrobots.com/robot_mobot_2007.shtml

[airman00]

slow in reaction compared to IR

[rox2007]

I was going to use photoresistors but i read in so many places on the internet that they are really slow in reaction

I disagree. The slowest of photoresistors have a full swing voltage time of ~100ms. The ones I use take like 20ms between a line and no line. Thats pretty darn fast.

Look at the photoresistor datasheet for proof

Ive made two robots that use photoresistors for line following:
http://www.societyofrobots.com/robot_mobot_2007.shtml

please where did you get them from. I have those ones from Radioshack, but when i utilized the equation from the photoresistor tutorial to find the resistor to use with a black line sensor. i got a large number of about 12kohms. am i on the right part?

And Admin, do you know how much Mc Master cost to ship or do you know somewhere cheaper to get HDPE?

[Admin]

i got a large number of about 12kohms. am i on the right part?

sounds reasonable. try it on a breadboard with a multimeter first if you arent sure . . .

do you know how much Mc Master cost to ship or do you know somewhere cheaper to get HDPE?

you can find many suggestions in the forum:
hardware store (homedepot, lowes), kitchen cutting board, mcmaster, etc.

do you know how much Mc Master cost to ship

hmmmm have you checked the site? i order all the time from mcmaster, but i always have my coworkers handle the ordering so i never see the final price . . . i don't remember it being too expensive, and i always get my stuff within 2-3 days, but depends on size/weight of what you order, too . . .

[SmAsH]

i have used mc master before to get HDPE for the $40 robot and the shipping price wasnt to bad to australia

[Kagi]

*cough* dollar store cutting boards *cough*   

[SmAsH]

i find that offensive! lol jk no i tried using the cutting boards first but didnt work to well. then i ordered...


~smash

[BANE]

SmAsh, what size board did you get and were was it shipped from?   Because a 24" x 36" is a different story$$$$$$$

*cough* dollar store cutting boards *cough*

lol, but it works!

bane