I did this YEARS ago with a lego mindstorms kit. Easy Peasy.

Posted at 1:24 am on May 9th, 2007 by Klintor

Several colored LED’s, I’m assuming you mean? Colored resistors :P.

Posted at 1:27 am on May 9th, 2007 by mrasmus

finally some color images on hackaday ! and look! capital letters!
:)

Posted at 3:01 am on May 9th, 2007 by TheBlunderbuss

I don’t know about you but I can make coloured resistors… it just depends on what shade of brown you want and how much current you’re willing to send through them. :-)

Posted at 8:44 am on May 9th, 2007 by akmixdown

Doh, Erik doesn’t since he didn’t use a valid email address.

Posted at 11:20 am on May 9th, 2007 by Will O\\\\\\\'Brien

damnit, I noticed that before the change, too, but I thought ‘meh, he means LEDs’…

aw.

neat hack though — I’m amazed at how fast the thing is. Seems that he indexed the carrier to the right edge of the track, since if you look closely it returns all the way to the edge before moving out to deposit an M&M. If he figured out how to use relative positioning, it could be even faster…
though then you might get some cumulative errors.

Posted at 3:19 pm on May 9th, 2007 by SL

will o\\\’brian, i wonder if i get a sticker for seeing that one lol. nice job by the way looking forward to doing this pretty soon as my final for electronics class.

Posted at 3:52 pm on May 9th, 2007 by Tony

I thought the 4.5x means it’s been sped up 4.5 times?

Posted at 7:51 pm on May 9th, 2007 by Wolfmankurd

The video is running 4.5x faster than real life, sl.

Posted at 11:07 pm on May 9th, 2007 by n3rrd

“light dependent resistor (I’m assuming he means a photo resistor)”

I think he meant light dependent resistor, LDR an established term.

Posted at 4:53 am on May 10th, 2007 by Graham

you can do it backwards with 1 white led and some LDRs with coloured filters on them.

and is photo resistor another name for light dependent resistor or are you thinking of something different because they are LDRs

Posted at 6:07 am on May 10th, 2007 by bender386

You don’t need to assume that is a foto resistor. The correct name is light dependent resistor or LDR as you can see in any databook

Posted at 8:19 am on May 10th, 2007 by Airton

so this thing actually takes about 4 and a half minutes to completely sort a bag of M&M’s ? the one in my class only takes about 2 minutes to sort 2 (measured) cups of colored erasers.

Posted at 4:05 pm on May 10th, 2007 by Tony

thats an interesting way to do it, with diff colored LEDs and photo resistor.

Whats the limiting factor of speed? I would guess the mechanics, but I can’t be sure.

Posted at 11:31 pm on May 10th, 2007 by Colin Karpfinger

The main factor with speed is the time it takes for the LDR to reach a stable resistance. In my project this is about 1/4 second. It could be less, I never made mesurments. just figured leaving it at 1/4 would be safe. And Yes I could have used multiple LDR’s with COlor filters, but the main problem with that would be the fact that I would need more then one ADC chip, at $4 a pop that would throw off my cost savings. And not to mention using more of my 32 pins on my Propeller board.

Posted at 10:19 pm on May 11th, 2007 by KLOZ