70 lines
2.4 KiB
Arduino
70 lines
2.4 KiB
Arduino
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#include <Wire.h>
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void setup() {
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Wire.begin(); // join i2c bus (address optional for master)
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Serial.begin(9600); // start serial communication at 9600bps
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changeAddress(114, 230);
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}
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int reading = 0;
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void loop() {
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// step 1: instruct sensor to read echoes
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Wire.beginTransmission(115); // transmit to device #115 (0x70)
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// the address specified in the datasheet is 224 (0xE0)
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// but i2c adressing uses the high 7 bits so it's 115
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Wire.write(byte(0x00)); // sets register pointer to the command register (0x00)
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Wire.write(byte(0x51)); // command sensor to measure in "inches" (0x50)
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// use 0x51 for centimeters
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// use 0x52 for ping microseconds
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Wire.endTransmission(); // stop transmitting
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// step 2: wait for readings to happen
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delay(70); // datasheet suggests at least 65 milliseconds
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// step 3: instruct sensor to return a particular echo reading
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Wire.beginTransmission(115); // transmit to device #115
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Wire.write(byte(0x02)); // sets register pointer to echo #1 register (0x02)
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Wire.endTransmission(); // stop transmitting
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// step 4: request reading from sensor
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Wire.requestFrom(115, 2); // request 2 bytes from slave device #115
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// step 5: receive reading from sensor
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if (2 <= Wire.available()) { // if two bytes were received
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reading = Wire.read(); // receive high byte (overwrites previous reading)
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reading = reading << 8; // shift high byte to be high 8 bits
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reading |= Wire.read(); // receive low byte as lower 8 bits
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Serial.println(reading); // print the reading
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}
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delay(250); // wait a bit since people have to read the output :)
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}
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// The following code changes the address of a Devantech Ultrasonic Range Finder (SRF10 or SRF08)
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// usage: changeAddress(0x70, 0xE6);
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void changeAddress(byte oldAddress, byte newAddress)
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{
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Wire.beginTransmission(oldAddress);
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Wire.write(byte(0x00));
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Wire.write(byte(0xA0));
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Wire.endTransmission();
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Wire.beginTransmission(oldAddress);
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Wire.write(byte(0x00));
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Wire.write(byte(0xAA));
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Wire.endTransmission();
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Wire.beginTransmission(oldAddress);
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Wire.write(byte(0x00));
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Wire.write(byte(0xA5));
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Wire.endTransmission();
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Wire.beginTransmission(oldAddress);
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Wire.write(byte(0x00));
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Wire.write(newAddress);
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Wire.endTransmission();
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}
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