Grovepi with SRF02 or SRF08 (ultrasonic with protocol I2C)


#1

If you want to use an ultrasonic in python with the I2C command (SRF2 or SRF08 for example) , you must create 2 files.
I create a filename directory : Grove_i2c_ultrasonic
i create a new file: grove_i2c_ultrasonic.py
the code is:

import time,sys
import RPi.GPIO as GPIO
import smbus

use the bus that matches your raspi version

rev = GPIO.RPI_REVISION
if rev == 2 or rev == 3:
bus = smbus.SMBus(1)
else:
bus = smbus.SMBus(0)

class ULTRA:
address = None

REG_ADDR_CONFIG = 0x00
REG_ADDR_RESULT = 0x02
CMD_ULTRA_INCHES  = 0x50
CMD_ULTRA_CM = 0x51
CMD_ULTRA_TIMER = 0x52

def __init__(self, address=0x70):
	self.address=address

self.command=command

bus.write_byte_data(self.address, self.REG_ADDR_CONFIG,0x20)

def ultra_read(self, address=0x70,command=0x51):
	self.address=address
	self.command=command

	bus.write_byte_data(self.address, self.REG_ADDR_CONFIG, self.command)
	time.sleep(.07)
	
	data=bus.read_i2c_block_data(self.address, self.REG_ADDR_RESULT, 2)
	raw_val=(data[0]<<8) | data[1]
	return raw_val

if name == “main”:
ultra= ULTRA()
while True:
print(ultra.ultra_read(0x70,0x51))
time.sleep(.5)

After i create a new file: i2c_ultrasonic_example.py
the code is:

import grove_i2c_ultrasonic
import time

You can initialize with a different address too: grove_i2c_ultrasonic.ULTRA(address=0x70)

ultrasonic= grove_i2c_ultrasonic.ULTRA()

while True:
#Print the 12 bit value from the I2C ADC
print(ultrasonic.ultra_read(0x70,0x51))
time.sleep(.5)

And now you can use a SRF02 or SRF08 :slight_smile:


UltrasonicRead Problem with Pi3
#2

Hi @stephane.roque,

Thank you for sharing the code on our forums.
We will test it and get back to you.

Again, thank you for your support,
Robert.