#!/usr/bin/python

import serial

import sys

import time

import string

from serial import SerialException

def read_line():

"""

taken from the ftdi library and modified to

use the ezo line separator "\r"

"""

lsl = len('\r')

line_buffer = []

while True:

next_char = ser.read(1)

if next_char == '':

break

line_buffer.append(next_char)

if (len(line_buffer) >= lsl and

line_buffer[-lsl:] == list('\r')):

break

return ''.join(line_buffer)

def read_lines():

"""

also taken from ftdi lib to work with modified readline function

"""

lines = []

try:

while True:

line = read_line()

if not line:

break

ser.flush_input()

lines.append(line)

return lines

except SerialException as e:

print "Error, ", e

return None

def send_cmd(cmd):

"""

Send command to the Atlas Sensor.

Before sending, add Carriage Return at the end of the command.

:param cmd:

:return:

"""

buf = cmd + "\r" # add carriage return

try:

ser.write(buf)

return True

except SerialException as e:

print "Error, ", e

return None

if __name__ == "__main__":

print "\nWelcome to the Atlas Scientific Raspberry Pi UART example.\n"

print(" Any commands entered are passed to the board via UART except:")

print(" Poll,xx.x command continuously polls the board every xx.x seconds")

print(" Pressing ctrl-c will stop the polling\n")

print(" Press enter to receive all data in buffer (for continuous mode) \n")

# to get a list of ports use the command:

# python -m serial.tools.list_ports

# in the terminal

usbport = '/dev/ttyAMA0' # change to match your pi's setup

print "Opening serial port now..."

try:

ser = serial.Serial(usbport, 9600, timeout=0)

except serial.SerialException as e:

print "Error, ", e

sys.exit(0)

while True:

input_val = raw_input("Enter command: ")

# continuous polling command automatically polls the board

if input_val.upper().startswith("POLL"):

delaytime = float(string.split(input_val, ',')[1])

send_cmd("C,0") # turn off continuous mode

#clear all previous data

time.sleep(1)

ser.flush()

# get the information of the board you're polling

print("Polling sensor every %0.2f seconds, press ctrl-c to stop polling" % delaytime)

try:

while True:

send_cmd("R")

lines = read_lines()

for i in range(len(lines)):

# print lines[i]

if lines[i][0] != '*':

print "Response: " , lines[i]

time.sleep(delaytime)

except KeyboardInterrupt: # catches the ctrl-c command, which breaks the loop above

print("Continuous polling stopped")

# if not a special keyword, pass commands straight to board

else:

if len(input_val) == 0:

lines = read_lines()

for i in range(len(lines)):

print lines[i]

else:

send_cmd(input_val)

time.sleep(1.3)

lines = read_lines()

for i in range(len(lines)):

print lines[i]