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December 22, 2014 12:25
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2 servos are controlled using the MPU6050
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#!/usr/bin/python | |
# KC6050Servos.py Reads MPU6050 and also drives 2 servos | |
# Initially written by Adafruit and developed by S&S Dec 2014 | |
import smbus | |
import math | |
import time | |
from Adafruit_PWM_Servo_Driver import PWM | |
# Initialise the PWM device using the default address | |
pwm = PWM(0x40) | |
# Note if you'd like more debug output you can instead run: | |
#pwm = PWM(0x40, debug=True) | |
servoMin = 150 # Min pulse length out of 4096 | |
servoMax = 600 # Max pulse length out of 4096 | |
# Power management registers | |
power_mgmt_1 = 0x6b | |
power_mgmt_2 = 0x6c | |
def read_byte(adr): | |
return bus.read_byte_data(address, adr) | |
def read_word(adr): | |
high = bus.read_byte_data(address, adr) | |
low = bus.read_byte_data(address, adr+1) | |
val = (high << 8) + low | |
return val | |
def read_word_2c(adr): | |
val = read_word(adr) | |
if (val >= 0x8000): | |
return -((65535 - val) + 1) | |
else: | |
return val | |
def dist(a,b): | |
return math.sqrt((a*a)+(b*b)) | |
def get_y_rotation(x,y,z): | |
radians = math.atan2(x, dist(y,z)) | |
return -math.degrees(radians) | |
def get_x_rotation(x,y,z): | |
radians = math.atan2(y, dist(x,z)) | |
return math.degrees(radians) | |
def setServoPulse(channel, pulse): | |
pulseLength = 1000000 # 1,000,000 us per second | |
pulseLength /= 60 # 60 Hz | |
print "%d us per period" % pulseLength | |
pulseLength /= 4096 # 12 bits of resolution | |
print "%d us per bit" % pulseLength | |
pulse *= 1000 | |
pulse /= pulseLength | |
pwm.setPWM(channel, 0, pulse) | |
xrot = 0.0 | |
yrot = 0.0 | |
def read_data(): | |
global xrot | |
global yrot | |
gyro_xout = read_word_2c(0x43) | |
gyro_yout = read_word_2c(0x45) | |
gyro_zout = read_word_2c(0x47) | |
accel_xout = read_word_2c(0x3b) | |
accel_yout = read_word_2c(0x3d) | |
accel_zout = read_word_2c(0x3f) | |
accel_xout_scaled = accel_xout / 16384.0 | |
accel_yout_scaled = accel_yout / 16384.0 | |
accel_zout_scaled = accel_zout / 16384.0 | |
xrot = get_x_rotation(accel_xout_scaled, accel_yout_scaled, accel_zout_scaled) | |
yrot = get_y_rotation(accel_xout_scaled, accel_yout_scaled, accel_zout_scaled) | |
# print "x-rotation: %.1f" %xrot+" degrees. y-rotation: %.1f" %yrot+" degrees" | |
pwm.setPWMFreq(60) # Set frequency to 60 Hz | |
bus = smbus.SMBus(1) # or bus = smbus.SMBus(1) for Revision 2 boards | |
address = 0x68 # This is the address value read via the i2cdetect command | |
# Now wake the 6050 up as it starts in sleep mode | |
bus.write_byte_data(address, power_mgmt_1, 0) | |
# Map servo rotation to MPU6050 orientation | |
slope = (servoMax-servoMin)/90 | |
middle = servoMin+(servoMax-servoMin)/2 | |
pwm.setPWM(11, 0, middle) | |
pwm.setPWM(15, 0, middle) | |
while (True): | |
servoPosx = middle+int(slope*xrot) | |
servoPosy = middle+int(slope*yrot) | |
read_data() | |
pwm.setPWM(15, 0, servoPosx) | |
pwm.setPWM(11, 0, servoPosy) |
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