Light Dependant Resistors (or LDR’s) are resistors whose value changes depending on the amount of ambient light, but how can we detect resistance with Arduino? Well you can’t really, however you can detect voltage levels using the analog pins, which can measure (in basic use) between 0-5V. Now the first thing that may need further explanation is the use of the Light Dependant Resistors. Or, if you are using an external power supply for the Arduino, you can use the Vin pin. Most motors require a higher voltage and higher current draw than this, so you will need an external power supply.Ĭonnect the motor to the H-bridge Connect the motor to the H-bridge as shown obve in 2nd picture. If your motor can run on 5V and less than 500mA, you can use the Arduino’s 5V output. The motor supply voltage connects to the voltage source for the motor, which is usually an external power supply. The motor logic pins are also connected to designated digital pins on your Arduino so you can send it HIGH and LOW to have the motor turn in one direction, or LOW and HIGH to have it turn in the other direction. In this Project, the enable pin connects to a digital pin on your Arduino so you can send it either HIGH or LOW and turn the motor ON or OFF. Included with the diagram is a truth table indicating how the motor will function according to the state of the logic pins (which are set by our Arduino). Above is a diagram of the H-bridge and which pins do what in our example.
The H-bridge has the following pins and features: Pin 1 (1,2EN) enables and disables our motor whether it is give HIGH or LOWPin 2 (1A) is a logic pin for our motor (input is either HIGH or LOW)Pin 3 (1Y) is for one of the motor terminalsPin 4-5 are for groundPin 6 (2Y) is for the other motor terminalPin 7 (2A) is a logic pin for our motor (input is either HIGH or LOW)Pin 8 (VCC2) is the power supply for our motor, this should be given the rated voltage of your motorPin 9-11 are unconnected as you are only using one motor in this labPin 12-13 are for groundPin 14-15 are unconnectedPin 16 (VCC1) is connected to 5V. The small DC motor you are using in this lab can run safely off a low voltage so this H-bridge will work just fine. It can drive up to 1 amp of current, and operate between 4.5V and 36V.
It has two bridges, one on the left side of the chip and one on the right, and can control 2 motors. The L293NE/SN754410 is a very basic H-bridge.
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