Line Sensor

Today we were trying to get the line sensor work, and it didn’t look like it’s working.
The line sensor shows these:
Yellow and Red

We said Green is detecting black, and for others we said it’s not.

What we were supposed to get was to know if the line sensor works on the carpet. So we tried on the carpet, and it shows Green, Yellow, and Yellow and Red when we were trying on the same carpet.

We gave up, and I didn’t get why it was like that.

Why was it like that?


Its a digital input, hook up the brown to the negative and the blue to the positive, the black is normally closed and the white is normally open. Hack a pwm cable so that the black and white line up (read: soldering iron).

Have Fun :stuck_out_tongue:

We got all of them, but we don’t get why it shows all of the 3 sign (Green, Yellow, Yellow and Orange)…

I hope nobody follows this advice. It’s completely wrong.

Brown is the positive supply to the sensor, and needs to come from the red terminal of a 20 Amp circuit on the Power Distribution board (or from an output on the solenoid breakout if you want to use 24 volts instead). Blue is the power return (ground), and should come from the adjacent black terminal on the Power Distribution board.

Either black or white can be connected to the SIGnal pin of a Digital Input on the Digital Sidecar. The LabVIEW autonomous line-following sample code expects the white wire.

Blue is negative and Brown is positive, that’s what a site on the internet was saying…

We’ve been using Blue as negative and brown as positive and nothing has broken by us doing it.

Which is exactly the setup Alan described and is the opposite of what you originally posted.

I agree.

Robototes2412, please remove/correct your post.

So in this setup, what is done with the black wires? Just connect them (a) to nothing or (b) to each other?

Neuter them. (Cut them off).

That’s what I thought. The kids managed to tear out several wires yesterday, and I wanted to be sure how to re-wire them properly (and am limited on time before build).

I won’t GIVE them the answer, but I wanted to be sure what the answer IS so that I can check their work and make ‘suggestions’…

Okay, there seem to be two points to this if I’m correct, the wiring and what those $@#$@#$@#$@# outputs mean.

Wiring: Blue is power and Brown is ground. They must be plugged into the power distribution block to receive the voltage they need (there may be another way, but this is what we found online, tried, and it worked). The black and white wires are “Light Output” and “Dark Output”. You only need one of these for the sensor to really work. The light output makes the sensor read true when it’s over light, while the dark does the same when the signal drops below the threshold. As such, you actually only need to run the white OR black wire on a pwm with only the signal wire to get the output you want on the Digital Sidecar.

As for the lights telling you what output you’re getting, they’re relatively simple if you read the paper that came with the sensors. Green means the sensor is A. receiving power and B. not giving output. If it’s over the line, it shouldn’t be showing green, since the output is energized. At the same time, your yellow light should turn on. The yellow light means the sensor is reading true, so it should toggle along with the green. The orange light is a little more confusing. When it is on, it means the sensor is receiving at least 2.5x the required signal strength to give a true output. What this really means is that the sensor is more certain that what it is seeing is the correct thing, not just background noise. This should only light up a a certain range from the target, and it’s not actually necessary for tracking the line.

Hope this helps!

NO! This is backwards! Alan’s post has the correct wiring description.

That works, until it doesn’t work.

See the bottom of Page2 and the top of Page3 of this document.