MARBLE MAZE ACTIVITY - Build a handheld marble maze that you control by tilting. If you like, make it interactive by using a series of electronic sensors, and control them with a handheld programmable brick*.

	Create a handheld marble maze using materials around your house or classroom - could be plywood and square wooden dowels like we have or it could be cardboard and drinking straws. Try making obstacles to avoid, like holes in the bottom or sides - or tunnels that cause your marble to magically switch direction! Get creative with paint, stickers, or just odds and ends laying around!
	Create a handheld marble maze with an attached copper sensor that turns on a small light (or a motor) when a metal marble passes over the sensor. For instructions on how to build this, check out the Marble Machine Activity.
	Build a high-tech marble maze with a copper sensor and control a motor with a handheld programmable brick *.

Things you'll need to do this activity:

* Before You Begin: This activity involves using a handheld programmable computer, developed by great folks at the MIT Media Lab, called a cricket. Powered by a nine volt battery, the cricket can control two motors and receive input from two sensors. If you don't have access to a cricket, you can use the commercially available Lego RCX brick and compatable software (Robolab or Mindstorms).

If you do have access to a cricket, you will also need an alligator clip sensor connector and a motor connector. Here's a link to making your own sensor/connector that will fit with a cricket.

For programming, we're going to use Java-based software, also developed by the MIT Media Lab, called Cricket LogoBlocks. If you have access to crickets, it's likely that you have this software as well. If you're using an RCX brick, the Mindstorms or Robolab software is equally functional.

Step 1: Start building your maze - we're using an 8" square piece pf plywood and 1/8" and 1/4" square wooden dowels for the walls of the maze. You certainly can use other materials - for example cardboard and drinking straws could also work. Make sure you leave enough room between the walls for your marble to easily move through the maze.

Step 2: Now let's build our sensor and add it to the maze. We want our ball to pass between the copper pieces and turn on a motor. (1) Clip the alligator clips to each of the copper strips and glue then in place on the maze with the copper folded over the edge of the maze. (2) Plug the other end of the alligator clip sensor into the sensor A spot on the cricket.

Step 3: Attach the motor connector to the top of the Lego motor and plug the motor connector into the "motor A" slot on the cricket.

Step 5: Now it's time to write a program on the computer and download it to the cricket. We're going to write a simple program that when the sensor is triggered - a motor will turn on for 30 seconds. Open up Cricket LogoBlocks (or similar program if you are using an RCX Brick, for instance, Robolab). (1) Click on the orange "control" button in the lower left hand menu and drag the wait until block underneath the purple start icon on the main page. They should snap together, and a red circle with the words "toucha?" will pop up. (2) Then click on "motor" in the menu and drag the "a" block underneath the "wait until" block. (3) Now drag the "onfor" block underneath the "a" block - a blue block will pop up with the number 10 showing - click on this block until a red outline appears around it and (4) change the 10 to 30 (by typing). LogoBlocks measures time in decaseconds, so 30 is equal to 3 seconds. Essentially, our program says "Wait until sensor a is touched, then turn motor a on for 3 seconds".

Step 6: Download your code onto the cricket by (1) placing the cricket in front of the interface cricket - make sure both are turned on and the infared receiver and transmitter are facing each other. (2) Under the Cricket menu, select "Download Code" from the drop-down menu. The LED lights on top should flicker while you are downloading.

Step 7: Click the white run button and test your program by placing the metal ball in between the copper strips.

Step 8: Now it's time to get creative - we just attached a simple sculpture of a woman with her suitcase (and her little dog, too!) on astro-turf - who will spin around when the sensor is triggered. Using just a Lego axle connector and axle we punched a hole through the bottom of our sculpture and secured it with glue. Of course, you can do anything you want - maybe you want a little pinwheel to spin around, or try building something more complex.

OTHER THINGS TO TRY:

→ Use a voice recorder and record your voice to be activated by the sensor.

→ Add a second sensor - if you have other types of sensors use them (reflectant, etc.)

→ Try attaching the copper sensor strips in a different way - make it more challenging to play!

→ Try making hidden tunnels with secret chambers with hidden surprises!