Need Assist in Programing Flowmeter and temperature sensor to the RaspberryPi (Python)

I have experience with the DS1620 temperature sensor.

If this DS18B20 is anywhere close to the DS1620, it's not the easiest temperature sensor to work with. Analog sensors use to be much easier as you just need a lookup table for taking temperature from the analog value read.

Those are digital temperature sensors and have a more or less complex communication protocol to get data out of them. They also use to have signaling - at least the DS1620 - where you program a max and min temperatures Th and Tl and the chip will trigger an alarm when the temperature is higher than Th or lower than Tl. The 1620 also have a Tcom pin that goes high from when one temperature is reached, to when the opposite temperature is reached so it can act as a standalone thermostat is you plug it to a fan or a heater.

I write this so you realize that may be those sensors are more complex than what you need to just make some temperature readings.

With this kind of thermistor TMP36 - Analog Temperature sensor [TMP36] ID: 165 - $1.50 : Adafruit Industries, Unique & fun DIY electronics and kits as example the temp reading is trivial Temp in °C = [(Vout in mV) - 500] / 10.

You just would need some marine heat shrink tube to isolate the sensor and solder it to a wire to have a working sensor like the other one you are linking. And much cheaper I guess.

Anyway if you have already bought the temp sensors, there is a Arduino library you can use with the ardupi or PiFace wiring libraries. That may be the easier path.

Ardupi - Cooking Hacks - Documentation - Raspberry Pi to Arduino shields connection bridge

PiFace wiring - PiFace | Wiring Pi

DS18B20 library - http://www.milesburton.com/?title=Dallas_Temperature_Control_Library

Don't try the same path with the flow meter arduino example though as it uses interrupts, and those are completely different beasts in Arduino and raspberry. In the raspberry you can use separate processes for each reading so you don't need to use interrupts and use a dedicated process for each flow meter instead.

The flow meter you just need to count pulses,  and average the readings to get the flow so it's trivial to dead with it.

It just have a pinwheel with a magnet so each time it spins it sends a pulse when a hall effect sensor detects the magnet passing.

You will also need to calibrate it because I am sure the piping will have something to do with how much liquid is passing by on each spin.

You will also need to have a steady flow, because reflows -liquid going back - will make the pinwheel spin. This is a wild guess from the device description but something to take into account.

What libraries / languages you plan to use ?

... and ...

What kind of output you need ?

It may be easier to separate each sensor in a task and later on plug it all together than to try to get it all working at the same time.

I have experience with the DS1620 temperature sensor.

If this DS18B20 is anywhere close to the DS1620, it's not the easiest temperature sensor to work with. Analog sensors use to be much easier as you just need a lookup table for taking temperature from the analog value read.

Those are digital temperature sensors and have a more or less complex communication protocol to get data out of them. They also use to have signaling - at least the DS1620 - where you program a max and min temperatures Th and Tl and the chip will trigger an alarm when the temperature is higher than Th or lower than Tl. The 1620 also have a Tcom pin that goes high from when one temperature is reached, to when the opposite temperature is reached so it can act as a standalone thermostat is you plug it to a fan or a heater.

I write this so you realize that may be those sensors are more complex than what you need to just make some temperature readings.

With this kind of thermistor TMP36 - Analog Temperature sensor [TMP36] ID: 165 - $1.50 : Adafruit Industries, Unique & fun DIY electronics and kits as example the temp reading is trivial Temp in °C = [(Vout in mV) - 500] / 10.

You just would need some marine heat shrink tube to isolate the sensor and solder it to a wire to have a working sensor like the other one you are linking. And much cheaper I guess.

Anyway if you have already bought the temp sensors, there is a Arduino library you can use with the ardupi or PiFace wiring libraries. That may be the easier path.

Ardupi - Cooking Hacks - Documentation - Raspberry Pi to Arduino shields connection bridge

PiFace wiring - PiFace | Wiring Pi

DS18B20 library - http://www.milesburton.com/?title=Dallas_Temperature_Control_Library

Don't try the same path with the flow meter arduino example though as it uses interrupts, and those are completely different beasts in Arduino and raspberry. In the raspberry you can use separate processes for each reading so you don't need to use interrupts and use a dedicated process for each flow meter instead.

The flow meter you just need to count pulses,  and average the readings to get the flow so it's trivial to dead with it.

It just have a pinwheel with a magnet so each time it spins it sends a pulse when a hall effect sensor detects the magnet passing.

You will also need to calibrate it because I am sure the piping will have something to do with how much liquid is passing by on each spin.

You will also need to have a steady flow, because reflows -liquid going back - will make the pinwheel spin. This is a wild guess from the device description but something to take into account.

What libraries / languages you plan to use ?

... and ...

What kind of output you need ?

It may be easier to separate each sensor in a task and later on plug it all together than to try to get it all working at the same time.

Thanks for the replay.

I actually already have the thermal sensor working with this code

import os

import glob

import time

os.system('sudo modprobe w1-gpio')

os.system('sudo modprobe w1-therm')

base_dir = '/sys/bus/w1/devices/'

sensor1_folder = glob.glob(base_dir + '28-000004a8873d')[0]

sensor1_file = sensor1_folder + 'w1-slave'

def sensor1_raw():

  s1 = open(sensor1_file, 'r')

  s1lines = s1.readlines()

  s1.close()

  return s1lines

def sensor1_temp():

  s1lines = sensor1_ra()

  while s1lines[0].strip()[-3:] !='YES':

  time.sleep(0.2)

  s1lines = sensor1_raw()

  equals_pos = s1lines[1].find('t=')

  if equals_pos != -1:

  tempstarting = s1lines[1][equals_pos+2:]

  temp_c = float(temp_string) / 1000.0

  temp_f = temp_c * 9.0 / 5.0 + 32.0

  return temp_c, temp_f

while True:

  Print(sensor1_temp())

  time.sleep(1)

________________________________________________________________________________

Which prints out the Temperature data every second but my big problem is figuring out how to count the pulses of the flow meter or to count the time between the pulses to get the frequency. That is the part of the program that i need big help with.

Using Python

I have tried this code but i'm doing something wrong it seems.

________________________________________________________________________________

import os # importing OS module just in-case needed

import time # Importing Time module

import RPi.GPIO as gpio # Importing RPIO module as gpio

# Initializing GPIO ports

boardRevision = gpio.RPI_REVISION # Clearing previous gpio port settings

gpio.setmode(gpio.BCM) # Use real physical gpio port numbering

gpio.setup(22, gpio.IN, pull_up_down=gpio.PUD_UP) # setting pin 22 as pull up resistor

while True: # main loop continuously running

  gflowcount = 1 # setting loop execution count

  while gflowcount <= 2: # loop for getting two times to compare

  if (gflowcount == 1 & gpio.input(22) == True): # Executing loop at first loop

  gflowtime1 = int(time.time()*1000) # Getting time of first pulse

  gflowcount = gflowcount + 1

  else if (gflowcount == 2 & gpio.input(22) == True): # Executing loop at second pulse

  gflowtime2 = int(time.time()*1000) # Getting time of second pulse

  else:

  print ('error')

  freq = gflowtime2 - gflowtime1 # Calculating time between two pulses

  hertz = 1000.0000 / freq # Calculating frequency

  flow = hertz / (60 * 7.5) # L/S # Calculating L/S

while True: # loop running every 2 seconds to output the data

  print freq # Printing time between two pulses

  print ('time between two pulse')

  print hertz # printing the frequency

  print ('frequency')

  print flow # Printing L/S

  print ('L/S')

  time.sleep(2) # Pausing for 2 sec.