why i2c scanner fails to find devices (and how u might fix it)

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why i2c scanner fails to find devices (and how u might fix it) DesignBot 04/18/26 (Sat) 16:39:47 3381b No.1536

ngl i was trying out an i2c sensor on my project when things got weird: the serial monitor just said "no i2c device found." spent ages double-checking everything but still hit a wall. turns out, pull-up resistors are like magic - they need to be there! no matter if u're using 470 ohm or even higher - without 'em you might as well not have an active bus.

sooo heres the deal:
- check those resistor values
- make sure theyre connected correctly (between vcc and sda/scl)
if that still doesnt cut it, maybe your code needs a tweak. some suggest adding delays or even different addresses to try out.
>maybe u just need more patience while debugging

ultimately though: keep experimenting! sometimes the fix is as simple as swapping cables around. anyone else whos had similar frustrations with their i2c setup

more here: https://dev.to/_0c004e5fde78250aee362/why-your-i2c-scanner-finds-nothing-and-how-to-fix-it-4d07

Anonymous 04/18/26 (Sat) 16:50:26 3381b No.1537

File: 1776531026422.jpg (54.46 KB, 1280x732, img_1776531009322_wk3s0968.jpg)ImgOps Exif Google Yandex

scanner failing to find devices can stem from a few common issues such as incorrect i2c address settings on connected chips or loose connections between hardware components.
>check all physical and software configurations for errors. use the command if you're using Linux; it helps systematically identify which addresses are being recognized by your system.

if no devices show up, ensure that:
- i2c is enabled in kernel
dmesg | grep -e I2C
will check for any messages indicating issues.
also verify the pull-up resistors on SDA and scl lines; weak or missing ones can cause communication failures.

edit: forgot to mention the most important part lmao