Justin Zhang wrote:I have tried a EV design using an Arduino and VEX Quadrature Encoder. The problem was the Arduino could not count the rotations of the encoder fast enough, so when reaching high speeds it skipped rotations and decreased the distance it ran. Different types of programs (on Arduino IDE of course) affected the accuracy, so it seems to depend on how fast the program is. I've considered interrupts, libraries, etc.
I understand that many people use Arduinos for their EV. How do you guys run them to the correct accuracy?
Secondly, my arduino mega reads encoders in degrees of 90 when I need accuracy up to 360.
Please share some sample code?
Here is some code. Each white wire on the VEX encoder should be connected to pins 2 and 3 on the Arduino (these are the interrupt pins) and the black and red wires should be connected to ground and a power supply of 5V, respectively:
// Red - 5V
// Black - GND
const int encoder_a = 2; // use one white wire here
const int encoder_b = 3; // use the other white wire here
long encoder = 0;
void setup() {
Serial.begin(9600);
pinMode(encoder_a, INPUT_PULLUP);
pinMode(encoder_b, INPUT_PULLUP);
attachInterrupt(0, encoderPinChangeA, CHANGE);
attachInterrupt(1, encoderPinChangeB, CHANGE);
}
void loop() {
Serial.println(encoder);
}
void encoderPinChangeA() {
encoder += digitalRead(encoder_a) == digitalRead(encoder_b) ? -1 : 1;
}
void encoderPinChangeB() {
encoder += digitalRead(encoder_a) != digitalRead(encoder_b) ? -1 : 1;
}
2016 SONT: 5th Place Scrambler
2017 MIT: 1st Place Electric Vehicle
2018 MIT: 1st Place Helicopter, 6th Place Mousetrap Vehicle
2018 UPenn: 2nd Place Mousetrap Vehicle, 2nd Place Mission Possible, 3rd Place Helicopter
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