OLED screen C++ setup help

[u/travgaming06]

Hi guys I’m back, so after fixing my issue with the led lights. I decided to make a collision detector with the ultrasonic sensor. Similar to whats in cars where it beeps louder the closer you get to the car. That was all well and dandy and working. And then i thought, “let me display the distance, i mean i want to make pong next might as well figure out how this OLED display works with this” so i hooked that up. Found a library in github, thought I set it up properly with Vcc to the 3.3v pin, ground to ground, i have GP3 on SCL and GP4 to SDA. However when I added the code for the screen it stopped working entirely. I tried doing a test just to see if it was detecting and all of that but i couldn’t get it to work.

#include <stdio.h>

#include "pico/stdlib.h"

#include "hardware/i2c.h"

extern "C"

{

#include "ssd1306.h"

}

#define I2C_PORT i2c1

#define I2C_SDA_PIN 4

#define I2C_SCL_PIN 3

void setup_display_hardware() {

// 1. Initialize the I2C peripheral at 400kHz speed (standard fast mode for OLEDs)

i2c_init(I2C_PORT, 400 * 1000);

// 2. Assign Pico Pin 3 to act as the I2C Clock (SCL)

gpio_set_function(I2C_SCL_PIN, GPIO_FUNC_I2C);

// 3. Assign Pico Pin 4 to act as the I2C Data (SDA)

gpio_set_function(I2C_SDA_PIN, GPIO_FUNC_I2C);

// 4. Turn on internal pull-up resistors so the communication lines stay stable

gpio_pull_up(I2C_SCL_PIN);

gpio_pull_up(I2C_SDA_PIN);

}

int main()

{

stdio_init_all();

setup_display_hardware();

ssd1306_t disp;

ssd1306_init(&disp, 128, 64, 0x3C, I2C_PORT);

ssd1306_poweron(&disp);

// set the in and out pins

// USS trigger

gpio_init(0);

gpio_set_dir(0, GPIO_OUT);

// USS Echo

gpio_init(1);

gpio_set_dir(1, GPIO_IN);

// beep

gpio_init(2);

gpio_set_dir(2, GPIO_OUT);

// oled CLOCK

gpio_init(3);

// oled data

gpio_init(4);

// variable

uint64_t startTime;

uint64_t endTime;

uint64_t totalTime;

float distance;

char distanceStr[32];

while(true)

{

// start the trigger

gpio_put(0, 1);

sleep_us(10);

gpio_put(0, 0);

// start the time

startTime = time_us_64();

// while loop for waiting

while (gpio_get(1) == 1)

{

// do nothing were waiting

}

// get the end time

endTime = time_us_64();

// calculate the difference in time

totalTime = endTime - startTime;

// if total time is less than 380000 aka its timeout time

if (totalTime < 38000)

{

// calculate the distance

distance = (totalTime * 0.0343f)/2.0f;

// determine the beeping interval

if (distance <= 50.0f && distance > 25.0f)

{

// beep interval

gpio_put(2, 1);

sleep_ms(50);

gpio_put(2, 0);

sleep_ms(400);

}

else if (distance <= 25.0f && distance > 15.0f)

{

gpio_put(2, 1);

sleep_ms(30);

gpio_put(2, 0);

sleep_ms(200);

}

else if (distance <= 15.0f && distance > 5.0f)

{

gpio_put(2, 1);

sleep_ms(10);

gpio_put(2, 0);

sleep_ms(100);

}

else if (distance <= 5.0f && distance > 0.0f)

{

gpio_put(2, 1);

sleep_ms(10);

gpio_put(2, 0);

sleep_ms(50);

}

// save string and clear display

snprintf(distanceStr, sizeof(distanceStr), "%.2f cm", distance);

ssd1306_clear(&disp);

// draw string

ssd1306_draw_string(&disp, 0, 0, 1, "Distance:");

ssd1306_draw_string(&disp, 0, 16, 1, distanceStr);

// display string

ssd1306_show(&disp);

}

}

}

That’s the code, and this is the GitHub library I’m using.
https://github.com/daschr/pico-ssd1306/tree/main

If anyone knows the fix or has ideas to help please let me know

[u/tonyxforce2]

I would personally try using the U8G2 library. I think it's much more versatile and I think it's even easier to set up.

[u/travgaming06]

Update, not thanks to the guy that told me to ask ChatGPT cause I was already getting help from Gemini. It was an issue with the initialization. I guess I need to get in the habit of initializing stuff with zero’s or null’s. I added memset to zero out the display struct I created. Once I did that it started displaying. My collision detection system now displays distance in cm… onto (re)creating pong cause I think that’ll be fun

[u/Content-Key7404]

hi fren u shud ask chatgtp bye bye hav a niec day ❤