I'm trying to create a setup to blink a led and be able to control the frequency.
Right now I'm just printing 10s as placeholders for testing.
Everything runs and does what should, but getch is throwing me off.
freq = 1
while freq > 0:
time.sleep(.5/freq) #half dutycycle / Hz
print("1")
time.sleep(.5/freq) #half dutycycle / Hz
print("0")
def kbfunc():
return ord(msvcrt.getch()) if msvcrt.kbhit() else 0
#print(kbfunc())
if kbfunc() == 27: #ESC
break
if kbfunc() == 49: #one
freq = freq + 10
if kbfunc() == 48: #zero
freq = freq - 10
Now when it starts up, the freq change portion seems buggy like it's not reading all the time or I have to time the press just right. The break line has no problem whenever pressed though.
There should be only one kbfunc() call. Store the result in a variable.
E.g.: In your code if the key isn't Esc, you'll read the keyboard again.
from msvcrt import getch,kbhit
import time
def read_kb():
return ord(getch()) if kbhit() else 0
def next_state(state):
return (state + 1)%2 # 1 -> 0, 0 -> 1
freq = 1.0 # in blinks per second
state = 0
while freq > 0:
print(state)
state = next_state(state)
key = read_kb()
if key == 27: #ESC
break
if key == 49: #one
freq = freq + 1.0
if key == 48: #zero
freq = max(freq - 1.0, 1.0)
time.sleep(0.5/freq)
Related
since i didnt really get the Adafruit-Library going to read the sensor correctly, i started using PIGPIO to read the DHT22. It works and i can see the Temperature and Humidity. My problem is now, how do i get those values into InfluxDB to use them in Grafana.
I already installed my DB and connected it with Grafana and made a DB called temp. The connection worked, now i just need to input some data.
!/usr/bin/env python
# 2014-07-11 DHT22.py
import time
import atexit
import pigpio
class sensor:
"""
A class to read relative humidity and temperature from the
DHT22 sensor. The sensor is also known as the AM2302.
The sensor can be powered from the Pi 3V3 or the Pi 5V rail.
Powering from the 3V3 rail is simpler and safer. You may need
to power from 5V if the sensor is connected via a long cable.
For 3V3 operation connect pin 1 to 3V3 and pin 4 to ground.
Connect pin 2 to a gpio.
For 5V operation connect pin 1 to 5V and pin 4 to ground.
The following pin 2 connection works for me. Use at YOUR OWN RISK.
5V--5K_resistor--+--10K_resistor--Ground
|
DHT22 pin 2 -----+
|
gpio ------------+
"""
def __init__(self, pi, gpio, LED=None, power=None):
"""
Instantiate with the Pi and gpio to which the DHT22 output
pin is connected.
Optionally a LED may be specified. This will be blinked for
each successful reading.
Optionally a gpio used to power the sensor may be specified.
This gpio will be set high to power the sensor. If the sensor
locks it will be power cycled to restart the readings.
Taking readings more often than about once every two seconds will
eventually cause the DHT22 to hang. A 3 second interval seems OK.
"""
self.pi = pi
self.gpio = gpio
self.LED = LED
self.power = power
if power is not None:
pi.write(power, 1) # Switch sensor on.
time.sleep(2)
self.powered = True
self.cb = None
atexit.register(self.cancel)
self.bad_CS = 0 # Bad checksum count.
self.bad_SM = 0 # Short message count.
self.bad_MM = 0 # Missing message count.
self.bad_SR = 0 # Sensor reset count.
# Power cycle if timeout > MAX_TIMEOUTS.
self.no_response = 0
self.MAX_NO_RESPONSE = 2
self.rhum = -999
self.temp = -999
self.tov = None
self.high_tick = 0
self.bit = 40
pi.set_pull_up_down(gpio, pigpio.PUD_OFF)
pi.set_watchdog(gpio, 0) # Kill any watchdogs.
self.cb = pi.callback(gpio, pigpio.EITHER_EDGE, self._cb)
def _cb(self, gpio, level, tick):
"""
Accumulate the 40 data bits. Format into 5 bytes, humidity high,
humidity low, temperature high, temperature low, checksum.
"""
diff = pigpio.tickDiff(self.high_tick, tick)
if level == 0:
# Edge length determines if bit is 1 or 0.
if diff >= 50:
val = 1
if diff >= 200: # Bad bit?
self.CS = 256 # Force bad checksum.
else:
val = 0
if self.bit >= 40: # Message complete.
self.bit = 40
elif self.bit >= 32: # In checksum byte.
self.CS = (self.CS << 1) + val
if self.bit == 39:
# 40th bit received.
self.pi.set_watchdog(self.gpio, 0)
self.no_response = 0
total = self.hH + self.hL + self.tH + self.tL
if (total & 255) == self.CS: # Is checksum ok?
self.rhum = ((self.hH << 8) + self.hL) * 0.1
if self.tH & 128: # Negative temperature.
mult = -0.1
self.tH = self.tH & 127
else:
mult = 0.1
self.temp = ((self.tH << 8) + self.tL) * mult
self.tov = time.time()
if self.LED is not None:
self.pi.write(self.LED, 0)
else:
self.bad_CS += 1
elif self.bit >= 24: # in temp low byte
self.tL = (self.tL << 1) + val
elif self.bit >= 16: # in temp high byte
self.tH = (self.tH << 1) + val
elif self.bit >= 8: # in humidity low byte
self.hL = (self.hL << 1) + val
elif self.bit >= 0: # in humidity high byte
self.hH = (self.hH << 1) + val
else: # header bits
pass
self.bit += 1
elif level == 1:
self.high_tick = tick
if diff > 250000:
self.bit = -2
self.hH = 0
self.hL = 0
self.tH = 0
self.tL = 0
self.CS = 0
else: # level == pigpio.TIMEOUT:
self.pi.set_watchdog(self.gpio, 0)
if self.bit < 8: # Too few data bits received.
self.bad_MM += 1 # Bump missing message count.
self.no_response += 1
if self.no_response > self.MAX_NO_RESPONSE:
self.no_response = 0
self.bad_SR += 1 # Bump sensor reset count.
if self.power is not None:
self.powered = False
self.pi.write(self.power, 0)
time.sleep(2)
self.pi.write(self.power, 1)
time.sleep(2)
self.powered = True
elif self.bit < 39: # Short message receieved.
self.bad_SM += 1 # Bump short message count.
self.no_response = 0
else: # Full message received.
self.no_response = 0
def temperature(self):
"""Return current temperature."""
return self.temp
def humidity(self):
"""Return current relative humidity."""
return self.rhum
def staleness(self):
"""Return time since measurement made."""
if self.tov is not None:
return time.time() - self.tov
else:
return -999
def bad_checksum(self):
"""Return count of messages received with bad checksums."""
return self.bad_CS
def short_message(self):
"""Return count of short messages."""
return self.bad_SM
def missing_message(self):
"""Return count of missing messages."""
return self.bad_MM
def sensor_resets(self):
"""Return count of power cycles because of sensor hangs."""
return self.bad_SR
def trigger(self):
"""Trigger a new relative humidity and temperature reading."""
if self.powered:
if self.LED is not None:
self.pi.write(self.LED, 1)
self.pi.write(self.gpio, pigpio.LOW)
time.sleep(0.017) # 17 ms
self.pi.set_mode(self.gpio, pigpio.INPUT)
self.pi.set_watchdog(self.gpio, 200)
def cancel(self):
"""Cancel the DHT22 sensor."""
self.pi.set_watchdog(self.gpio, 0)
if self.cb is not None:
self.cb.cancel()
self.cb = None
if __name__ == "__main__":
import time
import pigpio
import DHT22
# Intervals of about 2 seconds or less will eventually hang the DHT22.
INTERVAL = 3
pi = pigpio.pi()
s = DHT22.sensor(pi, 2, LED=16, power=8)
r = 0
next_reading = time.time()
while True:
r += 1
s.trigger()
time.sleep(0.2)
print("{} {} {} {:3.2f} {} {} {} {}".format(
r, s.humidity(), s.temperature(), s.staleness(),
s.bad_checksum(), s.short_message(), s.missing_message(),
s.sensor_resets()))
next_reading += INTERVAL
time.sleep(next_reading-time.time()) # Overall INTERVAL second polling.
s.cancel()
pi.stop()
from microbit import *
from ssd1306 import initialize, clear_oled
from ssd1306_stamp import draw_stamp
from ssd1306_img import create_stamp
from ssd1306_text import add_text
import utime as time
window = []
threshold = 550 # limit
count = 0
sample = 0
beat = False
start = False
good = create_stamp(Image.HAPPY)
bad = create_stamp(Image.SAD)
heart = create_stamp(Image.HEART)
values = []
def mean(datalist):
sum = 0
for i in datalist:
sum += i
if len(datalist) > 0:
return sum/len(datalist)
else:
return None
while True:
if button_a.was_pressed():
while True:
signal = pin1.read_analog()
window.append(signal)
avg = round(mean(window))
values.append(avg)
if len(window) == 11:
window.pop(0)
if beat is False and avg >= threshold+10:
beat = True
count += 1
display.show(Image.HEART, wait=False)
if count == 1:
t1 = time.ticks_ms()
if count == 11:
t2 = time.ticks_ms()
T = t2 - t1
bpm = round(600*1000/(T))
display.scroll(str(bpm))
initialize()
clear_oled()
add_text(0, 0, "Heart rate :")
add_text(0, 3, str(bpm) + " bpm")
if 60 <= bpm <= 100:
draw_stamp(38, 24, good, 1)
else :
draw_stamp(38, 24, bad, 1)
count = 0
sleep(2000)
if button_b.was_pressed():
break
count = 0
elif beat is True and avg <= threshold-10:
beat = False
display.clear()
sample += 1
if sample == 250:
threshold = mean(values)
values = []
sample = 0
sleep(20)
sleep(20)
This is the code connect to the microbit, and the function is about the heart rate sensor, which it will appear the average beat per minute when sensing 10 beats of the heart.
I am thinking of adding a function that if button b is pressed, the loop will pause, and press the button a to start again. I tried to add a break function in the loop, it worked when I click the button b, it pause the loop, however, the count of beat won't reset, and the time between the beat is also recorded although I break the loop.
Is there any way that I can break the loop and reset the count?
You should reset the counter before breaking. In your current code the line for the count is not executing since it breaks out before it reaches it.
if button_b.was_pressed():
count = 0
break
I'm trying to figure out how I can solve this issue. I have a Raspberry Pi that is set up with a breadboard that consists of:
1 RGB light
2 buttons (left and right)
1 OLED screen
Each component works and I can run each one. What I'm trying to do is write a script that will allow me to select the "mode" with the left button (everything off vs lights vs screen on).
When a mode is selected, the right button then allows me to select between options within that mode. Below is the code as I have it:
def off():
lights = [red,green,blue]
for light in lights:
light.off()
def lightSelector():
off()
number = 0
while number < 5:
if rightButton.is_pressed:
if number == 0:
off()
red.on()
sleep(1)
number += 1
elif number == 1:
off()
green.on()
sleep(1)
number += 1
elif number == 2:
off()
blue.on()
sleep(1)
number += 1
elif number == 3:
off()
row()
sleep(1)
number+= 1
else:
number = 0
def picture():
image = Image.open('grant.jpeg')
image_r = image.resize((width,height), Image.BICUBIC)
image_bw = image_r.convert("1")
for x in range(width):
for y in range(height):
oled.pixel(x,y,bool(int(image_bw.getpixel((x,y)))))
oled.show()
def oledOff():
oled.fill(0)
oled.show()
def buttons():
x = 0
y = 0
while y is 0:
print('x = ' , x)
print('y = ' , y)
if leftButton.is_pressed:
if x == 0 :
oledOff()
off()
sleep(0.5)
x += 1
elif x == 1:
oledOff()
off()
lightSelector()
sleep(0.5)
x += 1
elif x == 2:
oledOff()
off()
picture()
sleep(0.5)
x += 1
else:
x = 0
oledOff()
off()
buttons()
The idea is that the buttons() function is the main overall function and will call the others as needed. My issue is that once I get to y == 1, or the lightSelector() function, it no longer registers that the leftButton is being pressed and won't switch to the next mode and I'm stuck in the lightSelector() function.
I know at baseline I can spell out lightSelector within the buttons function instead of calling another function but I'm trying to not be as verbose. I don't have any experience with threading or multprocessing and looked into it but couldn't see how that would help.
I am trying to code ultrasonic sensors to count the number of cars in a parking lot. I am relatively new to Python, so I am asking here for help.
I have three parking slots, in which each of them has an ultrasonic sensor.
How do I make it so that the sensors and their counters work together? For example, when the parking slots are empty, the counter shows three parking slots available. When two parking slots are filled, the counter shows one availability, etc.
I have done the following code, and I am wondering how I could continue to achieve my objective?
# Sensor 1
def distance_1():
time.sleep(0.5)
GPIO.output(TRIG_1, True)
time.sleep(0.00001)
GPIO.output(TRIG_1, False)
print("Reading Sensor 1")
while GPIO.input(ECHO_1) == 0:
start = time.time()
while GPIO.input(ECHO_1) == 1:
end = time.time()
duration = end - start
sound = 34000 / 2
distance = duration * sound
round(distance, 0)
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
# Sensor 2
def distance_2():
time.sleep(0.5)
GPIO.output(TRIG_2, True)
time.sleep(0.00001)
GPIO.output(TRIG_2, False)
print("Reading Sensor 2")
while GPIO.input(ECHO_2) == 0:
start = time.time()
while GPIO.input(ECHO_2) == 1:
end = time.time()
duration = end - start
sound = 34000 / 2
distance = duration * sound
round(distance, 0)
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
# Sensor 3
def distance_3():
time.sleep(0.5)
GPIO.output(TRIG_3, True)
time.sleep(0.00001)
GPIO.output(TRIG_3, False)
print("Reading Sensor 3")
while GPIO.input(ECHO_3) == 0:
start = time.time()
while GPIO.input(ECHO_3) == 1:
end = time.time()
duration = end - start
sound = 34000 / 2
distance = duration * sound
round(distance, 0)
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
while True:
distance_1()
distance_2()
distance_3()
GPIO.cleanup()
The trouble with programming is there are so many ways to achieve the same result.
Looking at your code, I would suggest taking a step back and refactoring it to use Python classes instead. You have a lot of code repetition happening, and eventually, the code will break if you need to keep adding more sensors.
For example:
class Parking:
"This is a parking class"
def __init__(self, space):
self.space = space
def empty(self):
if self.space == 0:
print('Parking space is empty')
def full(self):
if self.space == 1:
print('Parking space is full')
def distance(self):
time.sleep(0.5)
GPIO.output(TRIG, True)
. . .
# Input:
sensor1 = Parking(1)
sensor2 = Parking(1)
sensor3 = Parking(0)
# Output:
sensor1.empty()
sensor2.empty()
sensor3.empty()
# Output:
sensor1.full()
sensor2.full()
sensor3.full()
You can then update a dictionary with the output to monitor the latest sensor information. Ideally, the dictionary would be written to a central file accessible by all the sensors or raspberry pis to read.
available_spaces = {"sensor1": 0, "sensor2": 1, "sensor3": 0}
I analyzed your code and I did some refactorings.
I suggest you to use constant values initialization (the config section you see in the code below). The values I used are random.
A function can be parametrized, so you can pass arguments to functions, and avoid writing the same piece of code changing only a few values in the same place.
You should set up your microcontroller when the script starts, to tell the board how you are using the pins (as input or output).
I didn't dig into on the snippet above the lcd_display_string and why are you doing those operations. I suppose that these are required to print on screen the distance.
## configuration
# trigger
TRIG_1 = 17
TRIG_2 = 27
TRIG_3 = 22
# echo
ECHO_1 = 10
ECHO_2 = 9
ECHO_3 = 11
# timings
INITIAL_DELAY = 0.5
TRIGGERING_DELAY = 0.00001
## support functions
# initializing GPIO
def set_up():
# set trigger GPIOs as output pins
GPIO.setup(TRIG_1, GPIO.OUT)
GPIO.setup(TRIG_2, GPIO.OUT)
GPIO.setup(TRIG_3, GPIO.OUT)
# set echo GPIOs as input pins
GPIO.setup(ECHO_1, GPIO.IN)
GPIO.setup(ECHO_2, GPIO.IN)
GPIO.setup(ECHO_3, GPIO.IN)
# I didn't dig into these values and why are you doing these operations. I suppose that these are required to print on screen the distance.
def print_distance_on_lcd(distance):
total = 3
count = total
if distance <= 10:
count -= 1
elif distance > 10:
count += 1
if count < 0:
count = 0
elif count > total:
count = total
print(count)
mylcd.lcd_display_string("{}".format(count), 2)
def trigger(trigger):
time.sleep(INITIAL_DELAY)
GPIO.output(trigger, True) # set output pin on HIGH state
time.sleep(TRIGGERING_DELAY)
GPIO.output(trigger, False) # set output pin on LOW state
def distance(t, echo):
trigger(t)
# initializing the variables here, allows you to use it outside the while block below
# using variable names that explains their content
start_time = time.time()
end_time = time.time()
# this block is not wrong, but unnecessary: initializing the variable like above is enough
'''
while GPIO.input(echo) == 0:
start_time = time.time()
'''
while GPIO.input(echo) == 1:
end_time = time.time()
duration = end_time - start_time
sound = 34000 / 2
distance = duration * sound
return distance
# call initialization function (this will be executed only one time)
set_up()
# loop forever
while True:
set_up()
print("Reading Sensor 1")
distance_sensor_1 = distance(TRIG_1, ECHO_1)
print_distance_on_lcd(distance_sensor_1)
print("Reading Sensor 2")
distance_sensor_2 = distance(TRIG_2, ECHO_2)
print_distance_on_lcd(distance_sensor_2)
print("Reading Sensor 3")
distance_sensor_3 = distance(TRIG_3, ECHO_3)
print_distance_on_lcd(distance_sensor_3)
GPIO.cleanup()
I'm trying to make a note application in Python using curses.
To the bottom left, should be a clock that updates every second.
The issue I now have is that it either has to sleep 1 second, or wait for input.
Is it possible to wait for input for 1 second and continue if no input it registered?
The reason I want to do this, is to prevent delay when moving around in the application.
I was thinking something like multi-threading would do the job, but got some issues there too.
This is the code I have so far:
#!/usr/bin/env python3
import curses
import os
import time
import datetime
import threading
def updateclock(stdscr):
while True:
height, width = stdscr.getmaxyx()
statusbarstr = datetime.datetime.now().strftime(' %A')[:4] + datetime.datetime.now().strftime(' %Y-%m-%d | %H:%M:%S')
stdscr.addstr(height-1, 0, statusbarstr)
time.sleep(1)
def draw_menu(stdscr):
k = 0
stdscr.clear()
stdscr.refresh()
threading.Thread(target=updateclock, args=stdscr).start()
cursor_y = 0
cursor_x = 0
while (k != ord('q')):
#while True:
stdscr.clear()
height, width = stdscr.getmaxyx()
stdscr.addstr(height//2, width//2, "Some text in the middle")
if k == curses.KEY_DOWN:
cursor_y = cursor_y + 1
elif k == curses.KEY_UP:
cursor_y = cursor_y - 1
elif k == curses.KEY_RIGHT:
cursor_x = cursor_x + 1
elif k == curses.KEY_LEFT:
cursor_x = cursor_x - 1
stdscr.refresh()
#time.sleep(1)
# Wait for next input
k = stdscr.getch()
curses.wrapper(draw_menu)
The code looks pretty messy, and it's the first time I've mainly focused on the curses function.
Is it possible to only wait for input k = stdscr.getch() for 1 second?
By default getch will block until you have a character input ready. If nodelay mode is True, then you will either get the character value (0-255) of the character that is ready, or you will get a -1 indicating that no character value is ready.
stdscr.nodelay(True) #Set nodelay to be True, it won't block anymore
k = stdscr.getch() #Either the next character of input, or -1