Raspberry Pi LESSON 33: Creating a Python Class and Library for Reading a Keypad

[@tntragan]

Most excellent lesson. I needed the reminder on how to make the classes and methods.

[@paulmcwhorter]

Excellent!

[@daveCotterill]

Another great Lesson. I'm really enjoying learning how these pieces of code, classes, methods and functions etc all interact with each other. Scrips of code are starting to make more sense to me now. Thank-you very much.

[@paulmcwhorter]

Great to hear!

[@LorenBurdette]

I started on this series when I bought the kit and have never used python before this. I really appreciate the way you go into and demonstrate and explain everything (even not cutting your mistakes). When going through the lessons on ADC, dht, and LCD I got curious about the setups for those libraries and really got a lot out of this lesson. Fantastic! Thank you.

[@paulmcwhorter]

Great to hear!

[@martinlewis645]

Great lesson. I had to go back to the old Python classes to review classes and methods.

[@paulmcwhorter]

Excellent!

[@keithlohmeyer]

Another great lesson this week. No homework so just stopped by to thank Paul for his commitment to teaching tech. Hard to believe that less than 2 years ago I had not written a single line of Python. Please keep up the good work!

[@paulmcwhorter]

Thanks, Keith

[@andrewnorburn]

really great lesson on the keypad. This lesson really showed that I need to go back and look a methods and classes again😀

[@ArjanvanderMeij]

This lesson has been really helpful! Thanks a lot!

[@opalprestonshirley1700]

You are the miracle man Paul. I've gotten behind a bit, love this lesson. Thanks for all your hard work. God Bless you and your family.

[@paulmcwhorter]

Welcome back, Opal. Had not heard from you in a while, we were worried.

[@scottwoods3413]

Another great lesson, you are shaping my future and wanted to let you know this , keep up with the videos; i'm doing the homeworks, however i have failed to record them and send them to share. BLESSINGS!

[@paulmcwhorter]

You can do it!

[@saad7267]

i literally cannot thank you enough sir, i have a competition next week where i have to code the program for an autonomous boat, and your arduino tutorials have been literally my knight in shining armor i dont what i would have done if not for you. you are such an amazing teacher it boggles my mind, wish i had encountered more teachers like you over the years. thank you and good health Mr. Paul

[@keithlohmeyer]

This one sounds fun. Can't wait!

[@paulmcwhorter]

This is a fun one. The keypad is just 16 pushbutton switches, which means it is easy to read a key with what we already know, but takes some thought to make a useful algorithm for really reading input from it.

[@OZtwo]

Yes, the last lesson was simply YET I used a function and not a class. So this video was very helpful in understanding classes in Python! Thank you!

[@paulmcwhorter]

Excellent!

[@michielverheyen1348]

I am legend! I like it when your solution is different from mine, so I'm still learning something new even though I did do the homework. Using the class and creating the library was super interesting. Thanks!

[@paulmcwhorter]

Great to hear!

[@jonathanlanders9406]

I am legend! I did go the easy route and just use a function, but I enjoyed watching the video after. The video gives a really great review on python classes (which I have not done in a while). One improvement on the code that I found helpful for debugging was to have the program print a '*' every time a button was pressed. This made it easier to see if the program was working right. This video was helpful as I am working on a portable microscope for some amateur ecology studies. I plan on using one of these cheap keypads for prototype versions of the microscope. Great video as always!

[@cbrombaugh]

Thanks for another most-excellent lesson Paul. I did the homework using a Python function, but I don't think I could have figured out all the selfie-class stuff. I look forward to more lessons that make use of the SunFounder devices. God bless you for all the time and effort you devote these lessons.

[@paulmcwhorter]

Great job!

[@stephenlightkep1621]

Thanks Paul! That was really cool. I have to look up your class and library tutorials because things are clicking.

[@davidschnider1297]

thanks, Paul....going to visit and take your earlier Python Tutorials .. where you introduce Threads, Functions, Methods and Classes.... yes...still having FUN.... learning...

[@paulmcwhorter]

Fantastic!

[@smitt76]

Thanks for explaining what a library is at a more fundamental level. I haven’t really understood what these things we’ve been importing are.

[@djbroake9810]

Awesome as always thank you.

[@paulmcwhorter]

My pleasure!

[@TheUnofficialMaker]

Great stuff!

[@paulmcwhorter]

Glad you enjoyed it

[@billgregg]

Thanks for the great lesson! This was my first foray into Functions, Class, Methods, Objects, and Libraries. There is so much for me yet to learn here...! You mentioned a previous lecture about these things if one wanted to learn more. I went to your website to try to find and view it. No luck, also don't see a link in description. I have also noticed that you don't have a lesson listing for this series like you do for the Fusion360 lessons(which will hopefully be my next project). I wonder what else is not clearly listed, because I think your teaching style is great, and I would like to take more of your online classes. Again, thanks! I appreciate you and all the hard work you put into your lessons.

[@alanabela1900]

I made a code that stores 5 characters. If more characters are pressed the first character of the string is deleted. When the D button is pressed, the code compares it to a password string. If the password is correct it will print a string keyword and the stored characters are deleted. If the D key is pressed when the password is wrong it will print "wrong password". I did not put this in a method tough.

[@peterwadham7965]

I folded like a cheap ...........This was my first foray into Functions, Class, Methods, Objects, and Libraries.

[@DrDave327]

I have been reviewing past lessons on functions, but can't quite figure out how to execute this with a function using a keypad and an LCD screen.

[@paulmcwhorter]

Watch upcoming lessons

[@brucemilyko8549]

I am legend. I made 2 functions one to get a string of characters. The second to get a single keypress. The first function needs the character to end the input, and return the string. It calls the second function that takes no input and returns the key pressed.

[@charlotteswift]

Great lesson. I had forgotten that you could put default values in the class init which you can then overrule. FYI You can avoid that long line (that everyone hated) by pressing return after every comma in the line (apart from within the inner '[ ]'s) and it will align itself nicely and still work. Small gripe, your Top Tech address hid some of the output. When I looked at the code a second time, something didn't look right. My Pi 4 is still out of action so I converted your code to run on my pico. I may have made a mistake but I think your cheap Walmart lawn chair has collapsed. If you put the main code into a while loop, it will print the string and then carrying on printing an empty string until you stop the program. I believe that you should have put ' noPress=True' and 'noPressOld=True' in the init rather than in readKeypad. Perhaps I am mistaken. I may have made a mistake in converting your code for the pico.

[@e4ent23]

Please add a lecture on Ros installing and using in raspberry pi

[@wilsonlittle4833]

Another great learning opportunity. Thank You. However, I had very little foundation for creating a "Class?" and really could have got more from the lesson. Somewhere you mentioned that you had presented this before. However, I've done each Raspberry Pi lesson (Arduino too), and I don't recall where this was covered. Is there another series that I would benefit from taking? p.s.: In the end I was successful in creating the library that used my prior keyboard program .

[@paulmcwhorter]

Look in my python playlist and I have a really good video on functions, methods, and classes. Well worth your time to watch that one.

[@ctlancearrowlarson8237]

I have a raspberry Pi 4 and I can’t get my audio to work. I have plugged computer speakers in the audio jack and no sound. Is there something I need to buy hardware, program software, coding etc. Has anyone had this problem and how was it solved? Would appreciate input on this.

[@paulmcwhorter]

pi has weak audio signal, might need some simple amp to drive speakers. Try earbuds and see if it works. Also, must have right plug type. Might also try bluetooth for an easier solution

[@keyboardlearning7552]

I have a Raspberry Pi 3b. I take the HDMI to my monitor, and take the Audio from the monitor socket. That works fine, too.

[@ctlancearrowlarson8237]

Thanks for both responses. I bought a new monitor that had HDMI and I also at the terminal ran sudo raspi-config then system options, s2 Audio, then selected headphones. Works fine now.

[@charlotteswift]

Here are my solutions to lessons 31 & 32 - kzbin.info/www/bejne/jnTJdIihYq-to8k

[@paulmcwhorter]

Nice work

[@davidschnider1297]

wow... thanks Paul.... interesting - and valuable lesson... but.. a little of a s t r e t c h for me - at this point - .. headed back to your Python Series .. to come up to speed.. with Classes, Methods etc ..

[@danrichardson3203]

Thank you. Very helpful, but there is no such thing as a silly ca video.

[@saad7267]

sir - follow up, i do really need some help about some of the parts of my code, because now my teammate actually built the robot, and once we are testing, we are facing alot of issues, its barely functional. is there anyway to contact u or anything please id appreciate it so much

[@paulmcwhorter]

I have 300,000 subscribers . . . how could I possibly provide individual help? Think . . . I am providing educational videos, I can not do the project for you.

[@saad7267]

@@paulmcwhorter oh sorry sir i didnt mean do the project for me, but yea i totally understand thank you very much regardless

[@MikhailEschatologist]

I'll look at your code if you like. Do you still need help?