Bad esp32 wifi connection after flashing with new esphome version

ESPHome
1

Hi everyone, this is a bit of a weird one. I've got an esphome node running since November 2025, which so far never had noticeable wifi issues. I had flashed it with a rather old esphome version back then, probably from early 2025 or even 2024. In February or March this year I upgraded our wifi to a unifi access point, and for the first time had an overview of the connection qualities of our individual wifi devices. Everything in the "green area", across all devices.
That changed after I recently decided to add new functionality to the node, and flashed that new code using esphome cli 2026.5. Since then, the node has a horrible wifi connection, which in turn leads to timeout issues with the new functionality I added (pulling data via REST from within the LAN). First I thought it could be a weak power supply, but switching to a 2.3A one didn't change anything.

To make things a bit more concrete: the red one is the problematic one.

image

These are the things that changed:

  • used esphome 2026.5 to compile and flash
  • added a rotary encoder to the esp32
  • added code that uses the http component to pull in data via REST

I do still want to rip out all the code changes and wires again to narrow it down, but as the wifi connection is continuously bad (without using the encoder or firing http calls), I'm still heavily wondering about the effects of the esphome upgrade.

Things I tried to improve the situation:

  • stronger power supply
  • switch from arduino to esp as the framework
  • tweaks in the wifi settings:
  power_save_mode: none
  post_connect_roaming: false
  output_power: 19.5dB

Hardware:

  • esp32 devkit v1
  • unifi 6+ access point

As mentioned above: there are still things I want to try, but if this combination of observations rings a bell for anyone: any help and hints welcome :slight_smile:

Thanks a lot!

2

Interferences, bad wiring, antenna disturbance with new hardware?

3

Has the ESP32 jumped to a further away Access point?

4

Will try without the new hardware still, yes

5

Nope, same/single access point, 2m away from the node

6

That suggests a HW failure with the RSSI numbers you shared. Could be the antenna. Could be a cheap esp32 that wasn't manufactured correctly/well.

7

Curiously, in another forum thread, someone suggested output_power : 8.5 improved their wi-fi connectivity, and several others agreed.

I was surprised that reducing output power to minimum would be an improvement, but if you are only 2m away it might be worth a try.

8

Reducing the transmit power reduces overloading of any receivers nearby. Even if not on the same frequency the front-end of the receiver becomes desensitised. That could be the reason the the suggestion works.

9

So I tried that now, and for now it pushed the signal level up to -80dbm. Still not where it was before, but definitely better. Will keep an eye on it, but will also still try the removing of the additional encoder plus wires. Thanks for the tips so far everyone :slight_smile:

10

I am going out on a limb here, but if your AP is close and it is seeing -80dBm signal level, your antenna or transmitter is marginal at best.

Take a different esp device and place it in the same location and see what you get.

Which esphome device are you using?
Is it on a breadboard?

Take pictures so we can see what you are and what you might be missing.

There are many C6 variants out there that have a poor design and benefit from the lower power output (since it helps keep them from rebooting due to a brownout of the power supply, on the board, not just the one on the wall).

11

Its a esp32 doit devkit v1, probably a clone though. The board is inside a 3d printed housing, with a screen module plugged directly into it via an adapter plug.

About a different device at the same position: i have a Waveshare ESP32-S3-Zero-based device sitting 3cm below it, both on top of my music amp. The s3-zero has zero (hoho) wifi issues, despite the ceramic antenna. I know that having the devices so close to eachother can be an issue, but it worked fine for months.

Later this week or on the weekend I'll have the time to try things out that require taking things physically apart, will follow up here with results, or at least photos :slight_smile:

12

That does point to something specific that is different. So, which one of these things is not like the others?

13

So, finally got around to take it apart and remove the extra wiring and the encoder. And suddenly the connection improves by another 5dbm, all “green” again:

image

Still not great for the distance to the access point, but running smooth. Guess i’ll either try to improve the wiring, or switch to an esp32 with a better antenna…

14

So what are you going to do now. Redesign or leave it?