Unfortunately it looks like these are some poorly designed clones, and the WiFi performance is horrible. They’re barely able to get -84 dBm, compared to -50 dBm for some other ESP32 boards from a different vendor. I’m running the same firmware on some other ESP32 boards that were a bit more expensive, and they have no problems at all.
These ones are only able to connect to WiFi if they’re a few meters away from an AP, otherwise they can’t connect reliably and constantly go offline.
I also saw a recent post about improved WiFi performance if the antenna is sticking out from the PCB, or if there is a notch cut in the PCB. There just seems to be plain PCB board under the antenna, without any copper trace. But I’m thinking about cutting out a notch in the PCB to test out this theory.
I’ve uploaded some pictures of the boards.
Has anyone else run into this before, and did you find a solution? Can you identify any problems that I might be able to fix? Is there a jumper I can resolder, or perhaps a way to fix it by attaching an IPEX Antenna?
Thanks for the link @zoogara! I had some spare 2.4GHz antennas so I just tried it out. It seems to work, and I’m getting around a ~10 dBm improvement. Hopefully that will be enough to make it reliable.
Aargh it turns out that it didn’t actually help too much. I also read online that it’s very difficult to hand solder an antenna for 2.4Ghz and get consistent results, since it’s very high frequency RF, so it has to be very precise.
Here’s some screenshots of the WiFi signals. The ones with 4-5 bars were expensive ESP boards that I bought from Surplustronics in NZ for $19 each. The ones with 1-2 bars are the cheap ones from AliExpress for around $6 each.
Or maybe it was because I ordered the “CH340 USB-C” version. Maybe there’s something wrong with this board design, or the chips they used.
Surplustronics are out of stock now, otherwise I’d just get more from them. I’ve ordered 3 more ESP32-WROOM-32D boards from different sellers on AliExpress. Hopefully at least one of these will work well, and then I’ll order a few more.
I decided I probably don’t need the external antenna for my ESPresense base stations, since I’ve got other boards that are working totally fine with the built-in antenna.
Hi, I had the same problem with an esp32 card the same as yours.
I did several tests (soldered an external antenna, changed the voltage regulator, added capacitors) which did not solve the problem.
I’ve seen a marked improvement in wi-fi performance by powering the board from the 5V (or 3.3V) pin instead of the usb connector.
I don’t know why, but it works well this way
Thanks so much for the tip @LoreNG, that completely solved my problem! I chopped all of my USB cables and twisted them together with some breadboard jumper wires. Plugged them in to the VIN and GND pins:
I won’t buy any more of these boards, but I’m really glad I was able to salvage them and use them as ESPresense base stations. Hopefully some of the other ones I ordered will work fine when they’re powered via micro USB.
Just came here to say thanks for the tip! @LoreNG I also had the same issue, and connecting 5V directly to the pins solved the issue. I ordered a bunch of those ESP32 devices and inside the hose they worked “fine” as in, they work mostly work autonomous and only occasionally they connect to the wifi and send some data to Home Assistant. Reception was not great, but it did not matter.
Now i started a project where i upgraded my outside weather center and an ESP8266 couldn’t cut it anymore Moved the code to an ESP32 and… What??? No WiFi reception in the garden? In the AP i’ve raised the maximum transmit power, disabled roaming, only enabled 2.4Ghz, and what not. In the end everybody and his mother has WiFi reception in the garden. I can almost FEEL the WiFi in the garden… but somehow this ESP32 in a small plasitc waterproof box couldn’t connect.
Indeed, connecting 5V to the VIN and GND pins solved the issue, with loads of dBa to spare. Restoring old config of outside AP now
Hey! I have the same problem. I thought it’s some issue with ESPresense but it’s caused ESP32 with CH340c chip… One of my ESP32 is an older, micro-USB model and works flawlessly.
Do you happen to know if CP2102 with USB-C connector is better or should I just buy micro-USB models in the future?
Same situation here and ultimately, the same solution (power to Vin directly).
And I can confirm the CH340C is the source of the WiFi woes. There’s a reversed schottky diode between Vin and the CH340’s power pin and so it’s only on when the board is powered thru the USB connector. And when the CH340 isn’t on, I get strong WiFi everytime.
Don’t know what’s wrong with the CH340. Counterfeit? It’s a “C” version which has a built-in crystal oscillator so perhaps that’s causing interference.
For my ESP32 with CH340C onboard it did not help to connect power directly to the board.
Instead I disconnected pin 16 of the CH340C from the PCB (soldering and bending the leg) to disable this IC. After that I have had no WiFi problems. Maybe the USB clock inside this IC can make interference with the WiFi signal, like user esp8285 mention, I don’t know…
I think pin 1 is at the top left (with the circle), so pin 16 is at the top right. I’m going to try to desolder and bend this pin and see if that fixes it!
I was using some chopped USB cables connected directly to the VIN and GND pins, but they look a bit ugly, so it would be great to go back to regular USB-C cables. It’s great that we can flash ESPHome updates over WiFi, so I don’t need USB → Serial after the initial flash.
Ali express is only the online store. Like Amazon. The quality depends on the seller. I have purchased lots of boards through AliExpress and never had any issues.
The same bullshit with esp wroom 32 with CP2102 USB chip.
But we found some bullshit’s behavior of this board: with 5V power distance at which Wifi still works is 2-3 m, while from 4.7 to 3.6 V - up to 45 m. One of strange thing with it is 5V on RX pin with 3.3 on TX when powered on from regular power supply for USB charging. If use USB from computer/notebook then real power is below 5V and it seems like there are no problems
