from machine import Pin
import time
import array as arr
class HX711(object):
GAIN = 1
SCALE = 1
OFFSET = 0
def __init__(self, dt, sck, gain = 128):
self.dt_pin = Pin(dt, Pin.IN, Pin.PULL_UP)
self.sck_pin = Pin(sck, Pin.OUT)
self.set_gain(gain);
def set_gain(self, gain):
if(gain == 128):
self.GAIN = 1
if(gain == 64):
self.GAIN = 3
if(gain == 32):
self.GAIN = 2
def tare(self, value = 1):
self.set_offset(self.read_average(value))
def set_scale(self, value):
self.SCALE = value;
def set_offset(self, value):
self.OFFSET = value;
def is_ready(self):
return self.dt_pin.value() == 0;
def is_read(self):
pass;
def wait_ready(self, delay_ms):
pass;
def get_value(self, count = 10):
return self.read_average(count) - self.OFFSET # add offset tare
def get_units(self, count = 10):
return self.get_value(count) / self.SCALE;
def read_average(self, count = 10):
sumValues = 0
for i in range(0, count):
sumValues += self.read();
time.sleep_us(1);
return sumValues / count;
def read(self):
value = 0;
data = arr.array('i',[0,0,0]);
filler = 0x00;
self.sck_pin.off();
data[2] = self.shiftInSlow();
data[1] = self.shiftInSlow();
data[0] = self.shiftInSlow();
for i in range(0, self.GAIN):
self.sck_pin.on();
time.sleep_us(1);
self.sck_pin.off();
if (data[2] & 0x80):
filler = 0xFF;
else:
filler = 0x00;
value = filler << 24 | data[2] << 16 | data[1] << 8 | data[0];
return value;
def shiftInSlow(self):
value8_t = 0;
self.sck_pin.off();
time.sleep_us(1);
for i in range(0, 8):
self.sck_pin.on();
time.sleep_us(1);
d = self.dt_pin.value()
self.sck_pin.off();
value8_t |= d<< (7 - i)
time.sleep_us(1);
return value8_t;
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