Optical Sensors

Yo,

How do you hook optical sensors up? I got one blue wire, one brown wire, one black wire, and one white wire. There is a diagram on that is a little confusing. What I did was I connect the brown wire to one of the digital input pins on the RC, and the blue wire to a ground pin. My result was the switch bit constantly set to 1. My impression from the diagram was to tie the black and white wire together, but it didn’t seem to change anything.

Also, I don’t have any reflective tape to test this with. I was trying to change the response by covering and uncovering the sensor but that was of no use. Do I absolutely need reflective tape?

There is an abbreviation that we have learned from various other teams. It is RTFM. R= Read, T=The, M=Manual. You can figure out what the F means. They supply a manual for a reason. Try reading it sometime.

Wow … I don’t know about you, but I came across RTFM on the programming scene–and it wasn’t very polite. Someone would ask a ‘begginer’ question, and someone else would feel that it waisted their time and they responded with RTFM. Anyway, back to the kinder, gentler first :slight_smile:

I don’t think covering your hand over it will set off the sensor, you need to cover it with a reflective surface (e.g. shinny metal). The two wires are there for conviniance, either nc (normally closed) or no (normally open). That just means that one will give a ‘1’ when nothing is sensed and a ‘0’ when something is sensed, and the other will be just the opposite. The other two wires are just ground and power, so I think you can handle them.

Stephen

*Originally posted by Ulibrium *
**
Also, I don’t have any reflective tape to test this with. I was trying to change the response by covering and uncovering the sensor but that was of no use. Do I absolutely need reflective tape? **

When the sensor is properly connected to power and ground, there will be some lights that come on, on the sensor.

You do not need the reflective tape, we were able to get it to trigger on someone’s hand from a few inches or a piece of sheet aluminum from a few feet. We were also able to get it to trigger on the reflective tape on someone’s backpack at 10-15 feet

Hook the brown to +, blue to -.

Don’t tie black and white together.

When nothing is sensed, the circuit for the white is closed and the black is open. When the light is reflected and sensed, the white is open and the black is closed.

Or is it the other way around… I’m just doing that off the top of my head…

Just hook both white and black to SEPARATE digital inputs and debug the variables. You can find out by trial and error. When you figure it out, you only really need 1 wire to detect 1 or 0.

If you are going to use the sensors as an input to the custom circuit board, you will have to have a pull up resistor. Without the pull up resistor your signal will look very lousy and probably will not do what you want it to do.

Joe J.

Despite the many acrimonius acronyms, The diagram on the side of the (last year’s*) sensor shows
-BU (Blue) connecting to relay contacts, through the ‘armature’ of the relay. These contacts are wired to WH(ite) and BK (black) wires. The rectangles are supposed to be ‘loads’ which are connected to the +BN (brown).

For those unfamiliar with Euro style colour codes
here they are (English Only, although the system is used in every language (What language uses G for yellow ?))

Bk Bn R O Y Gn Bu V Gy W
Black Brown Red Orange Yellow Green Blue Violet Gr(e/a)y White.

Notice Bk, Bn, and Bu, each starting with the same letter, but each having a unique 2nd letter (Bl is black, or is it blue ?). Green and Gr(e/a)y are taken care of similarly, and the (e/a) of dark white or light black doesn’t matter.

(*ours for 2002 still haven’t arrived from Manchester)

*Originally posted by hallty *
**There is an abbreviation that we have learned from various other teams. It is RTFM. R= Read, T=The, M=Manual. You can figure out what the F means. They supply a manual for a reason. Try reading it sometime. **

I saw this come up on #FIRSTRobotics

Read The First Manual!

…so I don’t know what YOU were thinking… :wink:

Ok… for all you people who reply RTFM, you are only wasting your own time by posting a useless message.

I don’t know which pin is for power. ACCORDING TO THE MANUAL… the digital input pinout is only comprised of digital switches and grounds. It doesn’t go Power +5 V, Input, Ground like the analog inputs do. So, for power, which one do I plug it into?

Also, I didn’t have lights go on. At least, I couldn’t tell that they were on.

But I did have a signal.

The diagram on the side didn’t help, because it only showed + and - for Blue and Brown. It didn’t really illustrate what to do with the White and Black.

From 2002 FIRST Robotics Competiton Manual, Section 2.1.6, page 12, Figure 2.4
Optical Sensor Wiring
Blue -> Digital Input Pin 3(Ground)
Brown -> +12 Vdc (From breaker on fuse Panel)
Black -> Digital Input Pin 15(Switch Input 3)
WHite -> Digital Input Pin 16(Switch Input 4)

Give me a link to the PDF version of this manual on First’s web site.

Ulibrium,
Dude! Hey you asked some good questions… ok first let me point out where the relavent documentation is.

You probably already have these files downloaded so bear with me please…
From the F.I.R.S.T. web site under documents and updates, under the competition documents there is the kit_p_hlist.pdf which is a very big PDF but if you have it, on page G-12 at the top there is the wiring diagram for the unit. The first diagram is of the NPN (sinking output) and is the basis for the example in the innovation First control system user’s manual. Open the System control manual to page 30 and refer to table 7.8
OK between the two sources, you get, that the brown wires from all your sensors get wired directly to a 12V breaker. From table 7.8 you can see that pins 3,6,9,12,13,14,17,20 and 23 all have ground so just take your pick and wire the blue wire to one of these pins. Now you’ve got power going to the sensor. The example shows wiring the black normally opened lead to pin 15 and the white normally closed output to pin 16, Because of the way the default rogram is written, these pins were resverved for relay 2 control and enables or disables the relay . You have another “freebie” in
relay 1 but using the same diagram and wiring pin 1 to normally opened black lead and pin 2 to the normally closed white lead of the sensor…pick one of the ground pins mentioned above and you now have a second sensor ready to go that programmatically controls relay 1.
If you want more relay control, you have to modify the default program.
When you power everything on you should see a red light coming from the optical sensor. If you can’t and you think there’s something wrong with the sensor, here’s a good trick. Cam Corder recorder systems are sensitive to the infrared outputs. look through the eyepiece of a cam corder at the sensor and you should see some light. IN fact, grab your TV or stereo remote control and look through the eyepiece while pressing a botton and you can see the infrared pulsing LED.
Hope this helps.

Best wishes

Steve Alaniz

*Originally posted by Ulibrium *
**Give me a link to the PDF version of this manual on First’s web site. **

It’s page 14 in this file:
http://www2.usfirst.org/2002comp/robot.pdf