Tag Archives: Python

Bodgers – More Distance Sensors

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This week we are going to try making a measuring device using our HC-SR04 sensors.

First we’ll wire our circuit up.

Next let’s test our circuit with the following code.

from machine import Pin
import utime
from time import sleep

trigger = Pin(17, Pin.OUT)
echo = Pin(16, Pin.IN, Pin.PULL_DOWN)
buzzer = Pin(15, Pin.OUT)


def ultra():
    trigger.low()
    utime.sleep_us(2)
    trigger.high()
    utime.sleep_us(5)
    trigger.low()
    while echo.value() == 0:
        signaloff = utime.ticks_us()
    while echo.value() == 1:
        signalon = utime.ticks_us()
    timepassed = signalon - signaloff
    distance = (timepassed * 0.0343) / 2
    print("The distance from object is ", distance, "cm")
    return distance


def buzz():
    buzzer.value(1)
    sleep(0.5)
    buzzer.value(0)
    sleep(0.5)


while True:
    dist = ultra()
    if dist < 30:
        buzz()
    utime.sleep(1)

This week’s challenge is to rewrite the code so the the closer to something the sensor is the faster it will beep.

Once we have that done we will look at transferring the code onto the Pico itself and running it from a battery.

Bodgers – Buttons

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This week we are looking at using buttons on our Raspberry Pi Picos.

Connect the LEDs and Buttons to the Pico as shown below:

Next use the code below to test the LEDs

from machine import Pin
from time import sleep

red_led = Pin(15, Pin.OUT)
green_led = Pin(14, Pin.OUT)

def blink():
    red_led.value(1)
    sleep(0.5)
    red_led.value(0)
    green_led.value(1)
    sleep(0.5)
    green_led.value(0)

while True:
    blink()

Next we’ll test the buttons using the following code:

from machine import Pin
from time import sleep

button_1 = Pin(18, Pin.IN, Pin.PULL_UP)
button_2 = Pin(19, Pin.IN, Pin.PULL_UP)

while True:
    if button_1.value() == 0:
        print("Button 1 is Pressed")
    if button_2.value() == 0:
        print("Button 2 is Pressed")
    sleep(0.1)

This week’s challenge is create a program called buttons_leds.py that turns on the red LED and turns off the green LED when button 1 is pressed and when button 2 is pressed will turn the green one on and the red one off.

Bodgers – Distance Sensors

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This week we will be using the HC-SR04 Ultrasonic Distance Sensor

Wire up the sensor as shown below

Here is the code we will need for the sensor.

#From www.tomshardware.com/how-to/raspberry-pi-pico-ultrasonic-sensor
from machine import Pin
import utime

trigger = Pin(17, Pin.OUT)
echo = Pin(16, Pin.IN, Pin.PULL_DOWN)

def ultra():
   trigger.low()
   utime.sleep_us(2)
   trigger.high()
   utime.sleep_us(5)
   trigger.low()
   while echo.value() == 0:
       signaloff = utime.ticks_us()
   while echo.value() == 1:
       signalon = utime.ticks_us()
   timepassed = signalon - signaloff
   distance = (timepassed * 0.0343) / 2
   print("The distance from object is ",distance,"cm")

while True:
   ultra()
   utime.sleep(1)

Once this is working you can move on to this week’s challenge. Combine this with the LED code from the last session so that the LED flashes when the distance measured by the sensor is less than 30CM. Here is the LED code:

from machine import Pin
from time import sleep

led = Pin(15, Pin.OUT)

def flash():
    led.value(1)
    sleep(0.5)
    led.value(0)
    sleep(0.5)
    
while True:
    flash()

Bodgers – Week 2

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Hi everyone, it was great to see you all last Saturday.

We worked on a car collision game here is our worksheet:

20231005Download

You can find the images for this game along with images for next week’s game here: https://www.dropbox.com/scl/fo/znirpob0ywen2kzwbgf6k/h?rlkey=ykhlgf8lbr4i35lu3ed8mrbrs&dl=0

Looking forward to seeing you all again next Saturday.

Declan and Kevin

Bodgers – Getting started with Python

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Hi Everyone

It was great to get back again with a full year to look forward to and it was also great to see so many people interested in getting involved with CoderDojo Athenry.

In the Bodgers group we got off to a great start, we installed the Mu Python editor, and we wrote our first few programs.

Bodgers

The Mu editor can be downloaded from here: https://codewith.mu/.

You can find our code from last Saturday on the last couple of slides from this week’s notes here: Bodgers Day 1

We also decided we’re going to do a few small projects between now and Halloween and then start on a bigger project after that.

Next week we are going to make a Space Invaders style game, you can find some images for it here: https://www.dropbox.com/home/Bodgers/Space%20invader/Images.

Looking forward to seeing you all next week.

Declan

Bodgers – A Look Back At 2020/2021

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Hello everyone,

I would like to thank all the Bodgers who joined me this year. I really enjoyed the sessions and I’m really grateful to you all for your attention, patience and your willingness to help me and each other out.

It’s a pity we couldn’t get together for even one session but hopefully when CoderDojo Athenry gets back to in person sessions I can meet you all then. I would also like to invite you all to our first post-COVID pizza party (hopefully before Christmas).

I have put together a video of the games we made this year.

Special thanks to everyone who created levels for our Red Runner game. You can find a copy of the code and images for this game on Dropbox here: https://www.dropbox.com/sh/sj6hil242d3fxmk/AAAHPnEVjw5IGWqs_G3eTXkDa?dl=0.

Thanks also to Kevin who helped us get up and running.

Enjoy the summer and hopefully I’ll see you in the autumn.

Declan

Bodgers –Magic Ball

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This week in the Bodgers group we revisited Pygame Zero and worked on a fortune telling game based on a Magic 8 ball.

I gave the group some artwork I prepared in the Paint.NET graphics editor and we wrote some code to animate them.

I’ve added the code and images to Dropbox here.

See you all on Saturday for Belts and Pizza, don’t forget to bring drinks.

Declan, Dave and Alaidh.

Bodgers – Texts & Emails

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This week we looked at sending texts and emails from our python scripts.

To send text messages you will need to set up an account on Twilio which is a platform that allows coders to make and receive phone calls, send and receive text messages from their programmes. You then install the Twilio python library which will allow us to send texts from our script using code like this.


# Download the helper library from https://www.twilio.com/docs/python/install
from twilio.rest import Client

# Your Account Sid and Auth Token from twilio.com/console
# DANGER! This is insecure. See http://twil.io/secure
account_sid = 'your account_sid'
auth_token = 'your auth_token'
client = Client(account_sid, auth_token)

message = client.messages \
                .create(
                     body="Hello Bodgers",
                     from_='+440123456789',
                     to='+353123456789'
                 )

print(message.sid)

To send an email we use smtplib which is an email library that’s built into python and which works well with Gmail. We need to change our Gmail setting to allow insecure apps and then we can use the code below to send our message.


import smtplib

server = smtplib.SMTP('smtp.gmail.com', 485)
server.starttls()
server.login("my.email@email.com", "myPassword")

msg = "Hello World"
server.sendmail("my.email@email.com", "some.email@email.com", msg)
server.quit()

See you all on Saturday

Declan, Dave and Alaidh

Bodgers – Pi Camera & OpenCV

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This week in the Bodgers group we looked at the Pi Camera Module which is a high quality image sensor add-on board for the Raspberry Pi. You can capture images  from the command line with:

 raspistill -o cam.jpg

This will take a jpeg picture called cam which will be saved in your home folder.

You can take a picture from your Python script with:


from time import sleep
from picamera import PiCamera

camera = PiCamera()
camera.resolution = (1024, 768)
camera.start_preview()
# Camera warm-up time
sleep(2)
camera.capture('foo.jpg')

This will save a picture called foo in the folder you ran your script from.

OpenCV (Open source computer vision) is a library of programming functions mainly aimed at real-time computer vision. We tried a couple of scripts out, one from the Hackers group, thanks Kevin, that detects colours and another one that detects shapes, we will be looking at this much more in the next few sessions but next Saturday we will look at using an Arduino and a Raspberry Pi together.

See you all then.

Declan, Dave and Alaidh

Bodgers – FreeCAD and Fritzing

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Hello again everyone

This week we continued working on our Astro Pi entries and we also looked at FreeCAD and Fritzing which are tools that will help us with building our projects.

fritzing_freecad

FreeCAD, available for download from here, is used for 3D modelling and allows us design very complicated things from simple 3D shapes such as cubes and cylinders. Here are a couple of quick videos to get you started.

Then we looked at Fritzing, download from here, an application for drawing very easy to understand circuits, here’s how to draw a simple circuit using it.

 

Dave will be leading next Saturday’s session and I will see you again on the ninth of Feb.

Declan, Dave and Alaidh.