Scratch Robots

1
Scratch Robots
Motor Controller
2
When the light sensor sees black, the motor is
OFF. When the light sensor sees white, the motor
is ON
Motor Controller
Radio Shack Parts 9.00 1-1/8 Modular IC
Breadboard 2.00 - IRF510 N-channel MOSFET
3.00 - Photo Resistors 3.00 - 22 Gauge Hookup
Wire 1.50 - 10K Potentiometer 3.00 - 9V
connector 2.50 - 9V battery --------------------
------ 24.00 - Total
Circuit Board
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3
Scratch Robots
MOSFET Motor Controller
Radio Shack Tools 9.00 Test Jumpers 3.00
Screw driver 7.00 Wire Strippers 20.00
Multimeter -------------------------- 39.00 -
Total
Tools
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4
Scratch Robots
MOSFET Motor Controller
6V to 9V
R1 Photo resistor 2K Ohms light (on) 50K Ohms
dark (off)
5V to 9V DC Motor 1A
D
G
R2 10K
S
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5
Scratch Robots
MOSFET Motor Controller
6V to 9V
R1 Photo resistor 2K Ohms light (on) 50K Ohms
dark (off)
5V to 9V DC Motor 1A
Q1 IRF510 N-channel MOSFET 2V-4V GS trigger
voltage 20V GS Max voltage 4A DS current G
Gate D Drain S Source
D
G
R2 10K
S
If the voltage between the Gate and Source of
this N-channel MOSFET is lt 2 volts, no current
can flow between the Drain and Source terminals.
The motor will not run. If the Gate to Source
voltage is gt 4 volts, then current will flow
between the Drain and Source and the motor will
run. Adjust R2 so motor is off when R1 sees no
light. The Gate voltage should be lt 2 volts.
When R1 sees light, its resistance should
decrease raising the Gate voltage gt 4 volts.
Then the motor will run.
Radio Shack Breadboard MOSFET On/Off
Controller Build-It-Yourself
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6
Scratch Robots
MOSFET Motor Controller
Voltage Divider (FET Gate Bias Control)
9V
VG 9V R2 R1R2

VG 9V 10K 4K(light)10K VG
6.4V
R1 Photo Resistor

VG
R2 Variable Resistor
VG 9V 10K 16K(dark)10K VG
3.4V

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