connecting more than 20 buttons/leds on the GPIO
March 4, 2024, 13:16
hi i am making a console that will have buttons and leds more than 20 and they will function with python but the problem is that i dont know how to extend the pins i think i need the product on the picture attached to this message if you can or cannot help please answer your help will be appreciated i will also need some help with the python part like the way it will read each 40 pins on the extender...
i will also pay with paypal 20 euros to the one who helped
Idk how to help you but why do you need 20 or more buttons??? Are you playing in the 5 dimension 💀😂
yeah its a tardis console
something like that
Oh I see
its a fan made project
I thinks it’s a good way to go
You also could use the MCP23017 chip
and attach it where?
in the breadboard
if you work with a breadboard ye
but Im not sure
i am planning on adding multiple breadboards like 4 of them on the r-pi 4 extender for the main panels and etc etc
Yes sure I dont see why not
now i am just waiting for the components to get delivered
the problem is how it will work with python
idk no I dont work with the raspberry 4 gpio pins xd
I would just use r pico's
whats r pico's difference? sorry i am kinda new to these whole stuff
The common way to do this is to put the button in a matrix 4x5 = 20 buttons
I'm new too xd but the pico is a microcontroller with gpio pins and its wayyy cheaper than a normal raspi
ooh okay
i see
And then you are using 9 GPIO pins for 20 buttons
oh that makes sense ye isn't it like led matrix?
Yes and thats called charlieplexing
each button does a different function in the console i am just reminding you
Well that's not a problem, you scan the keys, example:
Set pin 1 horizontal line HIGH, then you read the vertical lines one by one and detect a key press.
Then you continue with pin 2 horizontal line and 3 and 4
There are many example codes and probably libraries as well for your programming language in how to do this
all right
i dont really fully undestand it
but i got a small idea
And by adding a diode for each button you will improve the circuit, read more here https://www.gammon.com.au/forum/?id=14175
ill do my best and let you know if it worked
so i dont need an extender
?
If you have 9 GPIO pins you can make a 4x5 matrix = 20 buttons
understood
so what components should i use for charlieplexing?
do i need some sort of a chip?
Also we might have a problem not sure because i am new but as i can see right here we might wont be able to control what every button does and what and how many led lights on when the button pressed...
This is NOT charlieplexing, thats LEDs
its getting clearer thanks for that m8 i appreciate your patience
All learning has its steps. I was where you where some years ago so...
yeah you don't get born with knowledge i have more questions for later on now i have to go for a while
will this work?
i've added a led matrix that will actually be interactable with the buttons
wait a minute the led matrix is 4x1 instead of 4x5 oh for god shake sorry
there you go i fixed it
is the code correct? will each button toggle one led?
idk
Why post a picture of text?
uhm its just me talking to gemini ai
the problem is how will i set up the circuit like where and how should i put the leds and how the negative and positive will be connected to each led same with the buttons
Could you give me an image on how i should set this up?
Why not post the text as text, think about those that has sight impairment....
your absolutelly right i am sorry
there:
You're almost correct! Pressing "1" actually affects the first LED in row 1. Here's why:
Mapping Mismatch: The provided code defines the ledsRow and ledsColumn lists in a way that creates a slight mismatch between keypad buttons and LED positions.
The first element in ledsRow (L21) is connected to the first element in ledsColumn (Led1). However, these elements are labelled as "row 0" and "column 0" respectively, which can be misleading.
Actual Behavior: When you press "1," the following happens:
The readLine function activates the first row (L1) but checks all columns (C1, C2, C3, C4).
If the "1" button is pressed, the first element in ledState is toggled, affecting the state of Led1.
However, based on the mapping, Led1 corresponds to row 1, column 0 in the LED matrix.
Therefore, pressing "1" actually affects the first LED in row 1, column 0 of the LED matrix. The naming convention in the code can be a bit confusing, so it's important to pay close attention to the actual mapping between button positions and LED positions.
is that circuit diagram correct isn't this a 4x4 matrix? also R represents the resistors
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| R1|LED1| R2|LED2| R3|LED3| R4|LED4| | | | | | |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| R5|LED5| R6|LED6| R7|LED7| R8|LED8| | | | | | |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| R9|LED9|R10|LED10|R11|LED11|R12|LED12| | | | | | |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|R13|LED13|R14|LED14|R15|LED15|R16|LED16| | | | | | |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
<@796000224690307072> how should i connect this 4x4 matrix in the raspberry pi 4 B?
I have provided you with a URL earlier that explains it in details
which one?
The one above in the conversation
You should use IN instead of OUT? It’s a button right?
now ive setted up my raspberry pi 4 B and it says faild to open device 'sdcard'
never mind i needed a keyboard bruh
now its downloading the os but its tooooo slow like 7 kbps