EDUbot Sensors

How would you use the Optical Sensors for the EDUbot? What are they for? How would you program them?

What’s that gyro for? Where to mount it? How would you use it?

Thanks

These things came in the EduRobot kit? If they did we didn’t get them :confused:

I’m assuming they did…if they didn’t, I’ll have to ask how we got them…

The Edurobotics Kit from IFI, as supplied to teams, does not include any sensors or gyroscopes. It is only the Robot Controller, raw stock material, wheels, sprockets, chain, motors, bearings plates, etc.

Are you certain you’re not confusing the Edurobotics Kit (that comes in a small cardboard box) with a previous year’s Kit of Parts (that weighs 150 lbs. and comes into two brightly colored packing containers)?

Maybe that’s where they came from…now to rephrase the question:

How would we use those sensors with the EDUbot?

Maybe that’s the question I was to ask anyway.

Check:

http://www.chiefdelphi.com/forums/showthread.php?s=&threadid=1742&highlight=optical+sensors

http://www.chiefdelphi.com/forums/showthread.php?s=&threadid=2004&highlight=optical+sensors

http://www.chiefdelphi.com/forums/showthread.php?s=&threadid=1947&highlight=optical+sensors

http://www2.usfirst.org/2002comp/robot.pdf (Page 13)

That’s a start :slight_smile:

Our EduRobot kit came only with 2 limit switches for sensors

*Originally posted by marlon_jbt *
**How would we use those sensors with the EDUbot?

Maybe that’s the question I was to ask anyway. **

Check this thread. for a discussion of EduRobot Autonomy, and interfacing some of the sensors with the EduRobot kits.

-dave

Last year, I wrote some code that used 4 optical sensors to “lock-on” to a goal and find its range by triangulation. I never got the chance to use it in actual competition, but it worked flawlessly during testing and we currently use it as one of our “Wow!” features during demonstrations–nothing is more fun than watch the robot automatically aim its soccer-ball launcher at certain team members…

Anyway, if you want to see the code, its part of CogCode2k2, which is available at my website:
http://www.robbayer.com

Thanks everyone. I’ll have more info on Monday.

OK, I have more info.

We need to know how to program the Optical Sensors, and how to Program the Gyro. THIS IS ON THE EDUbot.

GYRO:

The gyro is an analog sensor whose output represents the rate of change of rotation around its axis. The axis is through the center, parallel to the mounting bolts. Connect the gyro to one of the analog inputs on the RC and start up the dashboard program. Hold it in the palm of your hand with the bolts facing outwards. When its not moving, the output is 127. Now twist your wrist to the like you’re turning the volume knob on the stereo. The value will increase in one direction and decrease in the other, proportional to the rate of rotation. When you stop moving, no matter what the final orientation is, it goes back to 127.

In your code, you will need to grab the value for the analog input you want to use. Say analog1 for arguments sake. Analog1 maps to the variable sensor1 in the default program. Make sure it is not commented out (line 50). Next, go down to the input constant definition section and enable sensor1 by setting the constant c_sensor1 to 1 (line 225). Add sensor1 to the SERIN command by inserting the variable where it belongs, based on the comments in the code.

Now, in your program you can use the gyro input to do something interesting.

BANNER OPTICAL SENSORS:

<edited>
several people posted a link to the data sheets in another thread:
www.chiefdelphi.com/forums/showthread.php?s=&threadid=15538
</edited>

These require 12V power, so I haven’t really played with them on the EDUbot. They fire out modulated infrared light and look for the reflection. Banner’s web site lists it as having about 6.5m range for reflective sensing, more than double that if you use a second sensor as a beacon. You connect it to a binary input on the RC, the value will be 1 or 0 depending on whether it sees the reflection.

PHYSICAL CONNECTIONS:

The analog inputs on the robot controller have 3 pins, +5V, signal, and ground from left to right. The binary inputs have two pins, signal and ground. Its looking for ground at the input pin, so DO NOT connect a voltage across the pins. These are compatible with female crimp connectors for radio controlled models, but they are expensive. You can order comparable parts from jameco.com:

3 pin connector housing, part number 100811, $0.27 each
2 pin connector housing, part number 157382, $0.27 each
female crimp pins, part number 100765, $0.11 each

I would buy 50% more pins than connectors, it takes practice to do it and you’ll mess a lot up. If you don’t have a crimper just get a servo extension from a hobby shop and you won’t have to worry about wiring it.

For the 3 pin connectors I bought 3 conductor bulk servo wire from a hobby shop, about $0.50 per foot. For the 2 pin connectors I used the cheapest speaker wire I could find.