Hardware Expansion

User Signals - These are available on connector J1 at the back of the bottom board. To access this area for soldering you will have to remove the 4 screws holding down the top plate, unscrew the 4 aluminum standoffs, separate the boards at connectors J2 and J3, and undo the 4 screws holding the bottom board to the motorized base.

	pin 6	-	port E7: A to D or digital input
	5	-	port E3: A to D or digital input
	4	-	port E2: A to D or digital input
	3	-	port A7: digital output (unbuffered), digital input, timer output, pulse accumulator
	2	-	port A0: digital input, timer input
	1	-	port A3: buffered inverted digital output

User Power - A variety of voltages are available on connector J5 near the top power switch. Again, you will have to remove the top plate and standoffs then separate the boards in order to solder wires into the holes.

	5	-	regulated +5 volts from switcher (keep load to under 100ma)
	G	-	system ground reference (zero volts)
	A	-	filtered +5 volts, use as an analog reference (low current draw)
	M	-	unregulated motor power, good for high current draws
	B	-	unregulated logic power (same as M for this model)

Hardware Ideas - There are a number of things you might want to add to your robot. To increase battery life use double- sided foam tape to attach a 4 AA cell holder to the aluminum top plate and connect the wires the same place as the red and black wires already on J5. Possible extra actuators include model airplane servos (J1 pin 3 can be used to generate different width pulses) or a motorized squirt gun (use J1 pin 1 to drive a switching transistor). For extra sensors you might add a pair of left/right photocells (use J1 pins 4, 5, or 6 to measure a resistive divider), a digital compass, a sonar ranging module (use J1 pin 2 to time the return echo), or a PIR (body heat) intruder detector.

Last updated 3/6/98