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我通過USB連接了Raspberry Pi和Arduino。 Arduino通過傳感器（EC和溫度傳感器）從世界上獲取數據並將這些數據寫入串口。 Raspberry將這些數據寫入數據庫。通過pyserial的樹莓Arduino通信在一天後停止
Arduino的草圖：在樹莓派
#include <OneWire.h>
#include <DallasTemperature.h>
int R1= 500;
int Ra=25; //Resistance of powering Pins
int ECPin= A0;
int ECGround=A1;
int ECPower =A4;
float PPMconversion=0.7;
float TemperatureCoef = 0.019;
float K=2.88;
#define ONE_WIRE_BUS 10 // Data wire For Temp Probe is plugged into pin 10 on the Arduino
const int TempProbePossitive =8; //Temp Probe power connected to pin 9
const int TempProbeNegative=9; //Temp Probe Negative connected to pin 8
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);// Pass our oneWire reference to Dallas Temperature.
float Temperature=10;
float EC=0;
float EC25 =0;
int ppm =0;
float raw= 0;
float Vin= 5;
float Vdrop= 0;
float Rc= 0;
float buffer=0;
void setup()
{
Serial.begin(9600);
pinMode(TempProbeNegative , OUTPUT); //seting ground pin as output for tmp probe
digitalWrite(TempProbeNegative , LOW);//Seting it to ground so it can sink current
pinMode(TempProbePossitive , OUTPUT);//ditto but for positive
digitalWrite(TempProbePossitive , HIGH);
pinMode(ECPin,INPUT);
pinMode(ECPower,OUTPUT);//Setting pin for sourcing current
pinMode(ECGround,OUTPUT);//setting pin for sinking current
digitalWrite(ECGround,LOW);//We can leave the ground connected permanantly
delay(100);// gives sensor time to settle
sensors.begin();
delay(100);
R1=(R1+Ra);// Taking into acount Powering Pin Resitance
};
void loop()
{
GetEC();
PrintReadings(); // Cals Print routine [below main loop]
delay(20000);
}
void GetEC(){
sensors.requestTemperatures();// Send the command to get temperatures
Temperature=sensors.getTempCByIndex(0); //Stores Value in Variable
digitalWrite(ECPower,HIGH);
raw= analogRead(ECPin);
raw= analogRead(ECPin);// This is not a mistake, First reading will be low beause if charged a capacitor
digitalWrite(ECPower,LOW);
Vdrop= (Vin*raw)/1024.0;
Rc=(Vdrop*R1)/(Vin-Vdrop);
Rc=Rc-Ra; //acounting for Digital Pin Resitance
EC = 1000/(Rc*K);
EC25 = EC/ (1+ TemperatureCoef*(Temperature-25.0));
ppm=(EC25)*(PPMconversion*1000);
}
void PrintReadings(){
Serial.print("Rc: ");
Serial.print(Rc);
Serial.print(" EC: ");
Serial.print(EC25);
Serial.print(" Simens ");
Serial.print(ppm);
Serial.print(" ppm ");
Serial.print(Temperature);
Serial.println(" *C ");
Serial.print("Vdrop: ");
Serial.println(Vdrop);
Serial.print("Rc: ");
Serial.println(Rc);
Serial.print(EC);
Serial.println("Siemens");
};
代碼：
import serial
import time
import re
import sqlite3
for com in range(0,4):
try:
PORT = '/dev/ttyACM'+str(com)
BAUD = 9600
board = serial.Serial(PORT,BAUD)
board.close()
break
except:
pass
DEVICE = '/dev/ttyACM'+str(com)
BAUD = 9600
s = serial.Serial(DEVICE, BAUD)
conn=sqlite3.connect('mydatabase.db')
cursor=conn.cursor()
#s.open()
time.sleep(5) # der Arduino resettet nach einer Seriellen Verbindung, daher muss kurz gewartet werden
#s.write("test");
while True:
response = s.readline()
numbers = re.findall(r"[-+]?\d*\.\d+|\d+", response)
if len(numbers) == 4:
temp = numbers[3]
ec = numbers[1]
result = cursor.execute("INSERT INTO sensordata (temp, ec) VALUES ({temp}, {ec})".form$
conn.commit()
print response
數據對樹莓側約24小時寫的，然後我從沒有Arduino的串行輸出了。同樣的問題，當我重新啓動python腳本。當我重新啓動python腳本並且串行通信再次啓動時，Arduino重置。我沒有改變這種默認行爲。我仍然沒有通過串口獲取數據的事實表明，在Arduino方面它沒有內存問題。還有一點提示，它必定是Raspberry的一個問題，我能從重啓Raspberry解決問題以及數據記錄24小時的事實中得到什麼。
有沒有人有足夠的好奇給我一個提示，如何建立一個堅實的溝通？
只是一些建議。在樹莓上爲主循環添加一些延遲，以便CPU不被100％使用。這可能不是問題，但它可能有幫助。在Arduino上添加GetEC函數中的其他序列打印（在樹莓上你會忽略），這樣你就可以看到它是否總是停在同一行。 – ChatterOne
Thx，ChatterOne供您評論。沒有收到任何電子郵件以識別您的活動。不知何故，python設法無論如何都增加了延遲。根據命令行工具頂部有很多空閒時間。是的，我在每條命令後添加了串行打印，這讓我進一步觀察，看到我的答案 –