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Line robot sensor

Hey guys, i want to build a line following robot and I was scouring ebay for some sensors


I found these but I wasn't sure if they would work, as I haven't done this before. They're pretty cheap.

These are even cheaper :)

Thanks Basile, and the LMR community.

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lumi's picture

They are a good choice to short distance like you need it for a line follower. I am using one in my R2D2 clone http://letsmakerobots.com/node/31848 and get a max. trigger distance of about 10-15mm depending on the light conditions. less than 5US$ for 10 of them is a good deal.

Just be careful, add the current limiter resistors or the LED will burn very soon ;-)

Dan M's picture

Decent price for 10 of them. Remember that the typical working distance for the TCRT5000 is ~5 mm.

It says 12 mm, but if you read further down the spec sheet, that is counting the height of the sensor itself which is ~7 mm, leaving 5 mm. I have some myself and they actually work to 6mm or more (1/4 inch) Of course, I am going into a rug rather than a hard surface so that does affect things, too.


I've considered adding them to Edwin, my start-here-variant robot to keep him from tumbling down stairs. Have not got that potential problem solved yet.


ADDED: From lumi's comments above, it sounds like there may be a wide variety in the sensors. That is further than mine function. Maybe it is a difference in who manufactured them. I can at least still say they work at a short distance. -not far at all, so they are best for line-following, or similar things where they are mounted near the floor. They could also be used in a gripper to tell if some ocject is within the gripper.  As I mentioned, I am thinking of using them to sence if the floor is there in order to "see" drop-offs and stairs.


birdmun's picture

Once you get the sensors, you could feed the outputs to a specific set of resistors and read the whole batch on an analog pin to figure out where the line is. :) Treat them like a switch matrix being read on an analog pin.

basile's picture

They do work.
For an example look here: http://letsmakerobots.com/node/29816
and here: http://letsmakerobots.com/node/29876