我使用的是覆盆子PI3和ADS1115,我的项目要求我获得均匀分布的样本,以便绘图和分析。其他职位是关于实现10公里和5万个sps,但我只需要500个sps,这也不起作用。有没有办法用500个sps运行我的代码120秒,同时从A0和A1通道获得60000个样本?我已附上代码以供参考。提前谢谢

from Adafruit_ADS1x15 import ADS1x15
import time
import numpy as np

pga = 2/3                  # Set full-scale range of programmable gain
                            # amplifier (page 13 of data sheet), change
                            #depending on the input voltage range
ADS1115 = 0x01              # Specify that the device being used is the
                            #  ADS1115, for the ADS1015 used 0x00
adc = Adafruit_ADS1x15.ADS1015()   # Create instance of the class ADS1x15

# Function to print sampled values to the terminal
def logdata():

    print "sps value should be one of: 8, 16, 32, 64, 128, 250, 475, 860,
    otherwise the value will default to 250"

    frequency = input("Input sampling frequency (Hz):     ")    # Get
                                               #sampling frequency from user
    sps = input("Input sps (Hz) :     ")                        # Get
                                           # ads1115 sps value from the user
    time1 = input("Input sample time (seconds):     ")          # Get how
                                           #long to sample for from the user

    period = 1.0 / frequency        # Calculate sampling period

    datapoints = int(time1*frequency)       # Datapoints is the total number
                               #of samples to take, which must be an integer

    startTime=time.time()                   # Time of first sample
    t1=startTime                            # T1 is last sample time
    t2=t1                                   # T2 is current time

    for x in range (0,datapoints) :     # Loop in which data is sampled

            while (t2-t1 < period) :        # Check if t2-t1 is less then
                                     #sample period, if it is then update t2
                t2=time.time()              # and check again
            t1+=period                      # Update last sample time by the
                                            #  sampling period

            print adc.read_adc(0, pga, data_rate=sps), "mV      ", ("%.2f" %
(t2-startTime)) , "s"      # Print sampled value and time to the terminal

# Call to logdata function
logdata()

最佳答案

1)您正在使用ADS1115吗???

adc = Adafruit_ADS1x15.ADS1015()   # should be adc = Adafruit_ADS1x15.ADS1115()

2)不能同时读取两个或多个单端频道。在差分模式下,可以比较两个通道以产生一个值。
要从通道1读取值,除了通道0,还必须在循环中添加另一个调用:
print adc.read_adc(0, pga, data_rate=sps) ..... # original call for channel 0
print adc.read_adc(1, pga, data_rate=sps) ..... # new call for channel 1

3)在读取一个值之前,ADS必须配置几个参数,如信道、速率、增益等。在进行模拟/数字转换所需的一段时间之后,在连续模式下,可以读取一次或反复读取值。
在最初的ADAFruit library中,此时间是根据数据速率(不安全)计算的,而在最近的端口中,此时间通常在0.01秒左右,因为在配置之后转换很可能没有直接完成(请检查CircuitPython)。
4)以500SPS的速度读取大约是ADS1115所能读取的最快速度。_read method表示在860SPS时转换需要1.2ms。添加配置和读取时间后,您将无法每隔0.002s连续读取两个或多个值,即使您正在接收转换通知(如我在reference中所述),而不是等待固定的时间段。
5)我认为最接近Python的方法是在GPIO通知的连续模式下运行2个菊花链ADS1115,但我没有这方面的经验。

10-07 15:09