Props to OP for using the term 'superstitions'. Wi-fi (and radio in general) is poorly understood even by people with engineering degrees, let alone the average Joe. This often leads to trying random stuff until an improvement is perceived (or believed to be...), then spreading this experience as proven and applicable in any context with no further research and confirmation of the results (let alone filing bug reports).
The prominence and accessibility (to laymen) of wifi does not help the situation either... I mean what else CAN they do except try stuff out, how are they going to determine that it worked and why it did?...
OP, yes, poorly implemented power saving has in my experience often been a culprit behind network reliability issues. That said, please consider adding a disclaimer that just disabling power saving in client devices without pinpointing the root cause of the instability or at least reporting it is exactly why we are in a situation where it is still buggy.
I love the term "superstition". I like to refer to lab "rituals" - if something works, repeat it, and never change things around "because it ought to work just as well". Life is too short to figure out all the unknown variables that might be affecting things, so seize luck when you find it.
If you have an ESP32C3 board with poor wifi performance, check if it's a boad with poor design that has the ceramic antenna is too close to the oscillator: https://roryhay.es/blog/esp32-c3-super-mini-flaw
YMMV but adding a loop of wire in parallel with the oscillator improved wifi performance on mine.
(I first tried moving the ceramic antenna a millimeter outward, but that made no difference.)
I was having multiple ESP devices from different brands running totally different firmwares all drop out randomly when I switched to a new Asus wifi router.
Came across even more 'work arounds'; No spaces in the SSID, disable IPv6 for the whole network even if the ESP ignores it. Thing is all of these settings would reboot the router and reconnect everything, so it would seemingly work until the next dropout.
I found limiting them to 802.11g instead of connecting with 'n' stopped the dropouts for good. Even now I wouldn't say that is a cure-all and that any of these other recommendations don't work, I'd guess that each AP's firmware might have different conflicts with different devices.
This one I've seen caused by N+ burst transmissions tanking the power rail, which causes acknowledgements to be dropped, which causes the esp to lower its TX rate so the TX takes longer...
> If your network hardware allows it, you should pin the device to the closest one.
In Wi-Fi it's always the client's choice on where to connect to at the end of the day and any hacks the APs try to do to steer clients are "suggestions" at best and "signal ruiners for everyone" at worst.
Alternatively, if you REALLY want to force it, the sanest way is to use a uniquely named IoT SSID on each AP so there would be no other option for those clients to choose to latch on to (and you can leave the other SSIDs shared for normal clients). E.g. "IoT-1", "IoT-2", "IoT-3" on 3 separate APs. It may clutter up device screens more when you list available networks but it's just visual because, as far as airtime, they all beacon just as often if the names are the same or not anyways.
> From what people and the internet tell me you should set the band width on the 2.4 Ghz network that your boards use to 20 Mhz, not 40, not 60, and definitely not automatic.
This is spot on in that 20 MHz is the ideal channel width on 2.4, doubly so for just an ESP32. Some things to add are I'd say it should apply to any of your 2.4 GHz networks unless you live out the sticks and really want to race a few extra mbps out at the fringe of your AP coverage (and even then the wider channel width is probably going to make your SNR worse even in the sticks). Also, I don't believe the ESP32 supports 60 MHz in the 2.4 GHz space at all (it's certainly not an option in the Wi-Fi standard).
I'll also tack on that the ESP32-C6 can be worth springing for if these kinds of thing are a particular concern as it support Wi-Fi 6, which has a few enhancements for connecting lots of IoT devices without so much noise.
If it's mainly (largely) static IoT devices connecting to an SSID, why not make the SSID hidden so it doesn't fill device screens (controlled by humans who probably don't want the IoT network)? Most commercial IoT products I've used have an option to type a hidden SSID, and your own C++ code definitely can do that.
Do you know of something that could get my Android tablet to switch between two AP's in my house? When I change locations in the house, it will never change to the stronger one if it has even the weakest signal that it was connected to. I can't find any Android app that tells the device to "change to a new AP if it is stronger than the current one".
But Arduino ecosystem is full of superstition and bizarre hacks. It's cargo cult electronics. They will do anything to avoid reading documentation or writing robust code.
Even the power saving recommendation here reeks of it. There is no effort to understand it. Someone on an Arduino forum recommends it, others start to echo it to try to appear like they know what they're talking about, it becomes lore in the Arduino world and you out yourself as a clueless newbie if you don't know to do esp_wifi_set_ps(WIFI_PS_NONE) without questioning anything because that's just the way it's done. It disables the radio in between AP beacons, so unless there's a bug in the implementation it should have no noticeable impact to a quiet WiFi station other than saving a lot of power.
I do actually see the problem that the ESP32 doesn't automatically reconnect to the stronger AP. I think this gets triggered when then stronger AP is briefly unavailable (reboot or radar scan or whatever) and it switches to the weaker AP, but then once the stronger AP is back it stays connected to the weak AP. (This is with multiple APs in a mesh configuration)
I wonder if the attempts to replace parts of the network stack with FOSS ( https://news.ycombinator.com/item?id=38550026 ) would help with this? At the very least it would let you get more visibility into what's going on when things don't work, and in the best case it'd let you replace the firmware that's creating problems with firmware that doesn't have those problems. (I think.) Of course this depends on the bits you replace being the parts in play.
2.4Ghz WiFi networks should use 20Mhz bands generally. No idea about specifically with ESP32s, but this is good guidance for not congesting the 2.4Ghz space.
I second that. In my experience forcing a 40MHz channel on a 2.4g network leads to abysmal performance (never tried it with ESP32, however I can imagine it would be even worse...).
>It seems that when an ESP32 connects it goes straight for the first access point it sees. No matter if that access point is not the one you’ve taped it to. This can lead to bad connectivity, especially since I’ve not really observed ESP32’s moving around to other access points.
This is not a characteristic of "ESP32", this is how the software running on the ESP32 is programmed to work, whatever specific program that is. And it is not my experience at all with "ESP32s". In my ESP-IDF based program, the ESP32 device connects to access points exactly how I tell it to connect with the software I wrote that deals with wifi connections. YMMV.
I encountered this a while back and it led me to dig into the ESP-IDF documentation to try to understand the behavior of a device I did not write the code for. Yes, it's software, but it's a footgun from the manufacturer. This in particular I find to violate the principle of least astonishment:
> It is a possible situation that there are multiple APs that match the target AP info, e.g., two APs with the SSID of "ap" are scanned. In this case, if the scan is WIFI_FAST_SCAN, then only the first scanned "ap" will be found.
The default if esp_wifi_set_config() is not called or, as I see in almost all the sample code that comes up with a quick web search, it is left untouched in the wifi_config_t struct, appears to be WIFI_FAST_SCAN. When you're looking directly at the relevant manual section during a HN discussion of ESP WiFI behavior, it may be obvious, but for a developer focused on the main product functionality who just copies and pastes an example and moves on when it appears to work, I'm not surprised if this always-incorrect-by-default behavior makes it into the vast majority of shipped ESP-based products.
I could have sworn there used to be a "sort by SSID" default, as in it would do the full scan and then connect to the AP with the alphabetically earlier hardware address. In any case, the symptom I was plagued with was that this particular device would consistently connect to the furthest-away access point rather than the one in the same room, resulting in unusable dropouts.
For people who are just trying to get a sensor to work, or control some lights, most esp32 frameworks surface maximum functionality, but minimum system state and next to no detailed debugging capabilities.
Combine that with very few “knobs” to turn on the esp32 framework, a router/wifi AP that is likely hostile to its owners, and well, superstition is pretty much all that is left.
It’s a demon haunted world.
Take note, those who dream of llms operating everything include each other: “prompt engineering” is just a fancy euphemism for grimoire, and when it’s all massive, inscrutable matrices deciding everything, well, you too might just feel it’s not a bad idea to build a shrine.
Funny how tweaking modern tech can still feel like adjusting rabbit ears on grandma's old TV - I swear my ESP32 runs better when it's cloudy outside or the microwave’s off.
This is not a superstition for 2.4GHz. Other devices sharing 2.4ghz tend to malfunction when 40MHz channels are in use. This is a well known phenomenon. I have been able to reproduce it in my household by enabling 40MHz channel support for 2.4GHz on my ruckus APs while listening to audio from a Bluetooth speaker. The Bluetooth speaker will start having discontinuities in the audio stream that disappear when 40MHz support in the APs is disabled.
I've had pretty good luck with the ESP line and WiFi, even have 2 of the 32s that have the port for external antenna working in sheds about 150' from the nearest AP.
I've always turned off power saving and given them hard coded IP settings (no DHCP). The only time I saw anything wonky is a short-lived experiment with the 32's deep sleep not reliably connecting on wakeup.
Mostly ESPHome now, two of the basic Uniquiti pucks from a few years back, for reference.
One of the culprits I encountered is that some of the IoT WiFi chips cannot do proper authentication if the AP is using WPA2/WPA3 mixed mode (very common for WiFi6 to increase security with modern devices while keeping backwards-compatibility). The flawed chips can initially connect successfully but disconnect after a few days.
Solved it by creating a dedicated IoT SSID advertising just WPA2 w/ AES and only on 2.4GHz w/ 20MHz (you shouldn't use 40MHz on 2.4GHz anyway for god's sake).
I created some sensor boards based on the ESP8266, they worked well for a while but lately they've been getting flaky. I'm a mediocre hardware engineer at best, so if anyone has any tips on how to make my board more stable, they would be appreciated.
Here's the board, it's a bit of a generic light/motion/presence sensor with an IR LED:
Do you know which aspect is getting flaky? Ie. Is the wifi dropping out temporarily, or permanently, or the whole MCU locking up, or the 3.3V browning out, or…?
Mine is to manually poll every once and a while and restart the WiFi if it's not connected. I generally find ESP32 WiFi to be very reliable.
I wonder if there's some special high security setting or OpenWRT router or something that they don't like?
Whenever tech people say something is unreliable, I sometimes wonder if they're using it in a non-stock way, and if that is part of what causes the issues.
This isn’t my area of expertise but I’m surprised there’s no mention of errata. Is that just not a factor at this point because the firmware is assumed to be mature enough?
I did a little dabbling in code for the ESP32 so I can't speak authoritatively at all, but I found that if your project does not require Wi-Fi, it was kind of annoying that the ESP32 would rob me of background cycles that, for example, the Teensy did not.
Maybe there was a way to turn off the Wi-Fi stack. But I suppose the general point still stands — that there are plenty of other small devices without Wi-Fi if that is not a requirement.
phoronixrly|11 months ago
The prominence and accessibility (to laymen) of wifi does not help the situation either... I mean what else CAN they do except try stuff out, how are they going to determine that it worked and why it did?...
OP, yes, poorly implemented power saving has in my experience often been a culprit behind network reliability issues. That said, please consider adding a disclaimer that just disabling power saving in client devices without pinpointing the root cause of the instability or at least reporting it is exactly why we are in a situation where it is still buggy.
pjdesno|11 months ago
deskr|11 months ago
It's worse. People don't even need to have personal experience to spread misinformation. They just read it online and then spread it like gospel.
Misinformation in the likes of "Wood glue it stronger than wood", "Burning Diesel/Kerosine can't reach temperatures required to melt steel".
rahimnathwani|11 months ago
YMMV but adding a loop of wire in parallel with the oscillator improved wifi performance on mine.
(I first tried moving the ceramic antenna a millimeter outward, but that made no difference.)
Calamityjanitor|11 months ago
Came across even more 'work arounds'; No spaces in the SSID, disable IPv6 for the whole network even if the ESP ignores it. Thing is all of these settings would reboot the router and reconnect everything, so it would seemingly work until the next dropout.
I found limiting them to 802.11g instead of connecting with 'n' stopped the dropouts for good. Even now I wouldn't say that is a cure-all and that any of these other recommendations don't work, I'd guess that each AP's firmware might have different conflicts with different devices.
bobmcnamara|11 months ago
zamadatix|11 months ago
In Wi-Fi it's always the client's choice on where to connect to at the end of the day and any hacks the APs try to do to steer clients are "suggestions" at best and "signal ruiners for everyone" at worst.
You may be better off specifying which specific AP you want to connect to by specifying the BSSID argument in the WiFi.begin() call on the ESP32 side https://github.com/espressif/arduino-esp32/blob/master/libra...
Alternatively, if you REALLY want to force it, the sanest way is to use a uniquely named IoT SSID on each AP so there would be no other option for those clients to choose to latch on to (and you can leave the other SSIDs shared for normal clients). E.g. "IoT-1", "IoT-2", "IoT-3" on 3 separate APs. It may clutter up device screens more when you list available networks but it's just visual because, as far as airtime, they all beacon just as often if the names are the same or not anyways.
> From what people and the internet tell me you should set the band width on the 2.4 Ghz network that your boards use to 20 Mhz, not 40, not 60, and definitely not automatic.
This is spot on in that 20 MHz is the ideal channel width on 2.4, doubly so for just an ESP32. Some things to add are I'd say it should apply to any of your 2.4 GHz networks unless you live out the sticks and really want to race a few extra mbps out at the fringe of your AP coverage (and even then the wider channel width is probably going to make your SNR worse even in the sticks). Also, I don't believe the ESP32 supports 60 MHz in the 2.4 GHz space at all (it's certainly not an option in the Wi-Fi standard).
I'll also tack on that the ESP32-C6 can be worth springing for if these kinds of thing are a particular concern as it support Wi-Fi 6, which has a few enhancements for connecting lots of IoT devices without so much noise.
Liftyee|11 months ago
venusenvy47|11 months ago
Vurdentium|11 months ago
But Arduino ecosystem is full of superstition and bizarre hacks. It's cargo cult electronics. They will do anything to avoid reading documentation or writing robust code.
Even the power saving recommendation here reeks of it. There is no effort to understand it. Someone on an Arduino forum recommends it, others start to echo it to try to appear like they know what they're talking about, it becomes lore in the Arduino world and you out yourself as a clueless newbie if you don't know to do esp_wifi_set_ps(WIFI_PS_NONE) without questioning anything because that's just the way it's done. It disables the radio in between AP beacons, so unless there's a bug in the implementation it should have no noticeable impact to a quiet WiFi station other than saving a lot of power.
shadowpho|11 months ago
No! You as programmer control that. You can configure to connect to any AP you want.
My code does a scan and save the closest AP. If it can’t connect it does another scan and saves a new AP
doormatt|11 months ago
ranma42|11 months ago
unknown|11 months ago
[deleted]
yjftsjthsd-h|11 months ago
denkmoon|11 months ago
bobmcnamara|11 months ago
File download time decreased by about 40% on Android but not at all on iOS - turned out at the time they only supported 40MHz+ on 5.8GHz.
phoronixrly|11 months ago
leptons|11 months ago
This is not a characteristic of "ESP32", this is how the software running on the ESP32 is programmed to work, whatever specific program that is. And it is not my experience at all with "ESP32s". In my ESP-IDF based program, the ESP32 device connects to access points exactly how I tell it to connect with the software I wrote that deals with wifi connections. YMMV.
masto|11 months ago
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/...
> It is a possible situation that there are multiple APs that match the target AP info, e.g., two APs with the SSID of "ap" are scanned. In this case, if the scan is WIFI_FAST_SCAN, then only the first scanned "ap" will be found.
The default if esp_wifi_set_config() is not called or, as I see in almost all the sample code that comes up with a quick web search, it is left untouched in the wifi_config_t struct, appears to be WIFI_FAST_SCAN. When you're looking directly at the relevant manual section during a HN discussion of ESP WiFI behavior, it may be obvious, but for a developer focused on the main product functionality who just copies and pastes an example and moves on when it appears to work, I'm not surprised if this always-incorrect-by-default behavior makes it into the vast majority of shipped ESP-based products.
And there's also
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/...
I could have sworn there used to be a "sort by SSID" default, as in it would do the full scan and then connect to the AP with the alphabetically earlier hardware address. In any case, the symptom I was plagued with was that this particular device would consistently connect to the furthest-away access point rather than the one in the same room, resulting in unusable dropouts.
freen|11 months ago
Combine that with very few “knobs” to turn on the esp32 framework, a router/wifi AP that is likely hostile to its owners, and well, superstition is pretty much all that is left.
It’s a demon haunted world.
Take note, those who dream of llms operating everything include each other: “prompt engineering” is just a fancy euphemism for grimoire, and when it’s all massive, inscrutable matrices deciding everything, well, you too might just feel it’s not a bad idea to build a shrine.
sourtrident|11 months ago
ryao|11 months ago
This is not a superstition for 2.4GHz. Other devices sharing 2.4ghz tend to malfunction when 40MHz channels are in use. This is a well known phenomenon. I have been able to reproduce it in my household by enabling 40MHz channel support for 2.4GHz on my ruckus APs while listening to audio from a Bluetooth speaker. The Bluetooth speaker will start having discontinuities in the audio stream that disappear when 40MHz support in the APs is disabled.
briHass|11 months ago
I've always turned off power saving and given them hard coded IP settings (no DHCP). The only time I saw anything wonky is a short-lived experiment with the 32's deep sleep not reliably connecting on wakeup.
Mostly ESPHome now, two of the basic Uniquiti pucks from a few years back, for reference.
riobard|11 months ago
Solved it by creating a dedicated IoT SSID advertising just WPA2 w/ AES and only on 2.4GHz w/ 20MHz (you shouldn't use 40MHz on 2.4GHz anyway for god's sake).
Here're some useful tips to tune WiFi for IoT https://www.wiisfi.com/#iotconnect
supakeen|11 months ago
stavros|11 months ago
Here's the board, it's a bit of a generic light/motion/presence sensor with an IR LED:
https://gitlab.com/stavros/sensor-board
taneq|11 months ago
eternityforest|11 months ago
I wonder if there's some special high security setting or OpenWRT router or something that they don't like?
Whenever tech people say something is unreliable, I sometimes wonder if they're using it in a non-stock way, and if that is part of what causes the issues.
pabs3|11 months ago
https://esp32-open-mac.be/
rkunde|11 months ago
maujim|11 months ago
> seriously, open up a device and changes are relatively large that you’ll find one
s/changes/chances
supakeen|11 months ago
JKCalhoun|11 months ago
Maybe there was a way to turn off the Wi-Fi stack. But I suppose the general point still stands — that there are plenty of other small devices without Wi-Fi if that is not a requirement.
mrtesthah|11 months ago
https://www.tarlogic.com/news/backdoor-esp32-chip-infect-ot-...
Vurdentium|11 months ago
[deleted]