Download proj-scratch-motor-ctrl - Build-It

Scratch Robots
Motor Controller
Motor
Controller
Circuit
Board
When the light sensor sees black,
the motor is OFF.
When the light sensor sees white,
the motor is ON
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
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Scratch Robots
MOSFET Motor Controller
Tools
Radio Shack Tools
$ 9.00 – Test Jumpers
$ 3.00 – Screw driver
$ 7.00 – Wire Strippers
$ 20.00 – Multimeter
-------------------------$39.00 - Total
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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
G
R2
10K
D
S
www.build-it-yourself.com
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
G
R2
10K
D
S
Q1
IRF510 N-channel MOSFET
2V-4V GS trigger voltage
20V GS Max voltage
4A DS current
G – Gate
D – Drain
S – Source
If the voltage between the Gate and Source of this N-channel
MOSFET is < 2 volts, no current can flow between the Drain and
Source terminals. The motor will not run. If the Gate to Source
voltage is > 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 < 2 volts. When R1 sees light, its resistance should
decrease raising the Gate voltage > 4 volts. Then the motor will
run.
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Radio Shack
Breadboard
MOSFET
On/Off Controller
Build-It-Yourself
Scratch Robots
MOSFET Motor Controller
Voltage Divider (FET Gate Bias Control)
9V
R1
Photo Resistor
VG
VG
R2
9V
= R1+R2
VG
10K
=
9V
4K(light)+10K
VG = 6.4V
R2
Variable Resistor
VG =
9V
10K
16K(dark)+10K
VG = 3.4V
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