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Schematic Diagrams

Below are some schematic diagrams that are useful for microcontroller and Arduino users.

Actuators

Connecting a coil, relay, pneumatic or hydraulic valve or solenoid

This schematic shows how to connect a coil, relay, pneumatic or hydraulic valve or solenoid to a binary or PWM pin. The MOSFET switch allows to connect different voltage devices to the I/O board that can't be directy connected to it. Verify that the voltage applied to the coil is in the range supported by it.

Connecting a generic digital device to a Binary or PWM pin

This schematic shows how to connect a generic digital device to a binary or PWM pin. The MOSFET switch allows to connect different voltage devices to the I/O board that can't be directy connected to it. Verify that the voltage applied to the digital device is in the range supported by it.

Connecting a generic HD44780 LCD Display

This schematic shows how to connect a generic HD44780 based liquid crystal display (LCD) to the I/O Board. Most displays have 14 pins to controll it, but others provide an additional pin for backlight voltage. A 10K Ohms potentiometer is used to control the contrast of the screen.

Connecting a generic Lamp

This schematic shows how to connect a generic Lamp to a binary or PWM pin. The MOSFET switch allows to connect different voltage devices to the I/O board that can't be directy connected to it. Lamps work better at specific voltages, verify that the voltage applied is in the range supported by the lamp.

Connecting a Light-Emitting diode (LED)

This schematic shows how to connect an LED to a binary or PWM pin. Typical values for the resistor r range from 100 to 470 Ohms.

Connecting a generic load to a Binary or PWM pin

This schematic shows how to connect a generic load to a binary or PWM pin. The MOSFET switch allows to connect different voltage devices to the I/O board that can't be directy connected to it. Verify that the voltage applied to the generic device is in the range supported by it.

Connecting a motor

This schematic shows how to connect a generic DC motor to a binary or PWM pin. The MOSFET switch allows to connect different voltage devices to the I/O board that can't be directy connected to it. Verify that the voltage applied to the motor is in the range supported by it. There is variety of motors available in the market and different factors like, voltage power, torque etc must be taken into consideration when choosing the right one for an application.

Connecting a motor using a L293D motor driver chip

This schematic shows how to connect a generic DC motor to a digital or PWM pin. The L293D motor driver chip allows to connect up to two DC motors to the I/O board. Verify that the voltage applied to the motor (Motor +V) is in the range supported by it. An optional 74HC10 Chip can be used to control the direction of the motors by using an additional I/O board digital output pin. There is variety of motors available in the market and different factors like, voltage power, torque etc must be taken into consideration when choosing the right one for an application.

Connecting a Servomotor

This schematic shows how to connect a generic servomotor to a binary pin. The servo Black wire is conencted to ground, the Red wire to +5V and the Yellow wire is connected directly to the microcontroller digital output pin. It's ok to power a servo from the I/O Board, but an external regulated power supply is recommended. If the servo is powered from a different power supply connect its ground and the I/O Board ground together.


Analog Sensors

Connecting a generic analog sensor

This schematic shows how to connect a generic analog sensor to a analog or binary input pin. In general analog sensors are variable resitors that change their resistance according to phenomena, like light, distance to an object, stretch, humidity, temperature etc.

Connecting a photoresistor

This schematic shows how to connect a photoresistor to a analog or binary input pin. The pthotoresistor is a variable resitor that changes its resistance according to the light intensity. It can be used to sense light intensity. Typical value for the resitor r is 1K Ohms.

Connecting a potentiometer

This schematic shows how to connect a generic potentiometer to a analog or binary input pin. The potentiometer is a variable resitor. The resistance is controllead by meas of a slider or rotating knob. It can be used to measure position or as a control to another phenomena. Typical value for the potentiometer resistance is 10K Ohms.

Connecting an Infrared SHARP GPD120 Ranger

This schematic shows how to connect an infrared SHARP GPD120 ranger sensor to a analog input pin. The ranger measures the distance to an obsacle. The GPD120 measures distance of objects in the range from 5 to 30 cm. The voltage returned is proportional to the distance to the obstacle.


Binary Sensors

Connecting a push button, or switch

This schematic shows how to connect a push button or switch to a binary input pin. Push buttons are open by default, when the user presses the button the switch is closed. Switches have 2 positions ON and OFF In the actual diagram the resisor r is called a pull-down since it is connected to Ground. typical value for r is 10K Ohms.

Connecting a hall sensor

This schematic shows how to connect a hall sensor to a binary input pin. Hall sensors set HIGH the signal pin when the sensor is near a magnetic field In the actual diagram the resistor R1 is called a pull-up since it is connected to +5v. typical value for R1 is 10K Ohms.


Communication Devices

Connecting a Parallax RFID reader

This schematic shows how to connect the Parallax RFID reader to your microcontroller. The RFID reader ENABLE pin can be connected to any digital I/O pin The RFID SOUT pin is connected to the Serial1 RX pin.


IC Sensors

Connecting a Devantech SFR08/10 Ultrasonic Ranger

This schematic shows how to connect the Devantech SFR08/10 Ultrasonic Ranger to your microcontroller. The Ranger SCL pin is connected to the SCL pin. The Ranger SDA pin is connected to the SDA pin.