IR sensors
 

What did the IR sensors come in or what do they look like? We are confused. If you have any information that would be great.

Re: IR sensors
 

The IR sensors came in the padded envelopes (the same one as the IR LEDS)
They are small, black, 3-leaded parts with a rounded dome on one side.

Re: IR sensors
 

They look like this.

-Kevin

Re: IR sensors
 

Ok, we found the "hardware" for the IR sensor. However, we're not sure about the mounting board shown on the instructions. Is it the one that is in the padded envelope? If so, do we cut it down to a smaller size? Any help is much appreciated.

Re: IR sensors
 

I think the piece of vectorboard is used to make the beacon (make sure you read the thread about the schematic error before you build this). The sensors are meant to be directly soldered to the end of a PWM cable or inserted into a connector that you build (this is what I did).

-Kevin

Re: IR sensors
 

Yeah we just used a bandsaw to cut our PCB to the exact size they had in the instruction.

By the way, remember that the instructions from the kit are wrong when it comes to wiring the transistor.

http://www.chiefdelphi.com/forums/sh...ad.php?t=23878

Re: IR sensors
 

Thanks for the help, we're going in the right direction now although we need clarification/help on the rest of the IR system.

As described we understand the IR sensors on the robot "seek out/home in on" the sensor(s) located near the 10 point balls. Did we receive the parts needed to create the "sensor" at the 10 point ball location? Are they the square "reflectors" (look like bicycle reflectors w/wires- 4ea) in the kit? If so, what are they connected to? Given Kevin's posts relating to "code" for these sensors (at the balls) it sounds like there is some type of "controller" (computer?) running this end of things. Correct?

Again, thanks for the help.

David M. Ellich
Coach, Team 1251
TechTigers/The Revolution
"Technology for the 21st Century"

Re: IR sensors
 

I also was wondering if the PWM connectors and the short wires depicted on the diagram that came with the beacon instructions are in the envelopes, because the one I have doesn't include them. Are they possible in the other envelopes for the other sensors. Also, Kevin, I'm not exactly sure how to wire up the sensor for our robot, such as you depicted. What does the sensor connect to? And, how does that connect to the controller? Thanks

Re: IR sensors
 

No, the "bicycle reflectors" you are referring to are the Team Color lights that must be mounted to your robot. These will flash red or blue depending on which side of the field your robot is assigned to.

The IR Beacons were shipped in pieces and must be assembled per instructions. You are correct to say that a controller is needed -- Code is provided to use the EduBot controller for this purpose.

Re: IR sensors
 

You were given enough parts to make 2 Beacons.
In the sensor bag you will find Printed Circuit board x1, IR Transmittors x10 resistors x8, switches x2, and connectors x2.

Print out the document http://www2.usfirst.org/2004comp/Inf...ng_diagram.pdf
And it will assist you in the parts identification.

Phil

Re: IR sensors
 

This document is still incorrect. Pin 2 and 3 of Q1/"HexFET" need to be reversed for it to work.

-Kevin

Re: IR sensors
 

Let me see if I have this straight.

The IR beacon parts in the kit are enough to build the two units (one for the robot and one at the balls). The EDUrobot controller is used with the beacon unit at the balls. Only thing left to do is use the appropriate code for each side.

Re: IR sensors
 

In what direction do the resistors neeed to be placed? And which part is the FET?

Re: IR sensors
 

It doesn't matter which way the resistors are attached. The MOSFET looks like the picture on the front of the data sheet.

-Kevin

Re: IR sensors
 

No, there is a beacon on each side of the field, both driven by one EDU-RC.

-Kevin

Re: IR sensors
 

THANKS! I just wanted to make sure, since I really don't feel like desoldering (it's such a pain!) Also, thanks for reminding me to switch pins 2 and 3, I never would've known (except when it didn't work!) Thanks again :D

Re: IR sensors
 

You have enough parts to build 2 beacons. Those beacons are placed on the center line of the playing field. Build one and power/controll it via your edubot.

That's the transmittor.

You then need to build the receiver for your robot.

Re: IR sensors
 

Where can I reorder another FET? One of the ones I had broke when I was trying to desolder it and switch pin 2/pin 3

Re: IR sensors
 

Digi-Key has 'em. The part number is IRL3103-ND.

-Kevin

Re: IR sensors
 

What is the exact size that we cut the victorboard? If there is somewhere I could find it, that would be great.

Re: IR sensors
 

The beacon parts are for the two beacons that will be on either side of the field. Neither gets mounted on the robot itself. Drive the beacons with the EDU controller running the beacon software provided at the IFI web site (labeled "IR Tracking Code - Kevin.org").

The robot gets just the one piece IR sensor (4 are assumed in Kevin Watson's code) hooked directly up to digital inputs 1-4. Drive these with the navigate software also in the download above.

Re: IR sensors
 

We ordered 2 more FETs just incase. Before I put the one on my second beacon, I just wanted to make sure which digram is correct. Is this one still wrong? http://www2.usfirst.org/2004comp/Inf...ng_diagram.pdf Should I still reverse the pins 2 and 3? I just wan to make sure again before I order more.

Re: IR sensors
 

That circuit is incorrect.
Luckily the FET seems to be internally protected against hooking it up incorrectly or teams would have been burning them out right and left.

On the FET looking at the front (with the metal ground plate at the back)
pin 1 on the left goes to the white (signal) wire on the PWM cable from the EDU controller.
pin 2 goes to the negative side of the circuit you built.
pin 3 goes to the black PWM wire (common or ground) from the EDU controller.

You can see an updated circuit diagram Kevin Watson posted at http://kevin.org/frc/ beacon_transmitter_2.pdf

You can only see your circuit running with a digital camera, or by hooking up one of the IR sensors to a digital input like 6 and adding a printf to print the value of rc_dig_in06 in the beacon code.

Re: IR sensors
 

Unfortuantely, even with the wrong circuit, you will still see the LEDs glow in the camcorder, in fact, the circuit actually functions with the Source and Drain swapped, but the resistors get REALLY hot. ( I tested it with the IR reciever and a scope, and the signal is there, just not as clean and not as far a range)

So why won't First fix the document error?????