I got the super small ESP32 C3 on aliexpress which is cheap vendor with black antenna instead of red as seen the picture.
The wifi signal is really bad (20% or less) if the modules are placed in different room of AP, couldn’t get them at all.
I did google and found solution to improve the wifi signal by solder the small copper wire on the antenna.
1 Like
And tin foil on your rabbit ears antenna gets better pictures.
Hogwash is the most generous description I have for this modification.
1 Like
thanks for suggestion. I’m going to print the small box and wire antenna should be good for wifi reception.
copied screenshots from one of the members here and his link
https://www.printables.com/model/582630-case-for-esp32-c3-super-mini-and-ld2410c
1 Like
Guessing you are too young to have done a Pringles Cantenna mod…
Might be worth watching:
2 Likes
Please share yaml code. my c3 supermini can’t recive data from LD2410.
Got it from here.
Blockquote
Blockquote
1 Like
I had the same problem (in fact two of mine wouldn’t connect to an AP on channel 11, and worked but with very weak signal on channel 1). The same solution worked for me; afterwards I can connect to channel 11 just fine, and the reported signal strength reported from the AP on channel 1 has improved by between 15 and 20 dB. I’m guessing that the antenna is either defective or maybe soldered on backwards or something. Mine were also the ones with the black/white antenna.
A 20dB increase would be an unimaginable power level. 20 dB corresponds to a hundred-fold increase in signal level. NO antenna short of a .5 meter parabolic dish can provide 20dB of gain.
Well, the AP went from reporting around -62dB to around -45dB, depending a bit on exact position and orientation. I’m assuming it is the difference between effectively ‘no antenna’ and ‘something approximating an antenna’.
I would also note that a different esp32-c3 board with a PCB trace antenna in the same place on my desk running the same binary gets reported at -33dB so it is definitely still not a good antenna!
Where are you reading “dB”? The RSSI (Received Signal Strength Indicator) is in dBm. (dB is relative and dBm is absolute). The RSSI value is only an indication of the signal strength that device is measuring at that moment on that device. 5 devices in the same location will give you 5 different RSSI readings.
Regardless, an RSSI of -62 is very good, -45 is remarkably good, and -33 is what I would expect with the device on top of the router.
Ahh yes you are right it is in dBm as reported by the AP management software.
These numbers are all from my desk directly under the ceiling mounted AP.
I think I’ve figured out what is going on here - indeed 20dB of gain would be insane, assuming your antenna is well matched to the transmitter. But these boards are broken in some way, and I expect there’s a horrible impedance mismatch between the transmitter and the antenna system, so rather than the energy from the transmitter being emitted as radio waves, it’s being reflected back to the transmitter and ultimately being lost as heat inside the board.
By adding the wire loop, we haven’t improved the antenna, we’ve probably just changed its impedance to be a bit closer to the rest of the system, so more of the energy is being converted to radio waves and a little less is being wasted as heat.
These broken boards have quite a different layout to the working ones with the red antenna - I wonder if the antenna matching system is actually set up for a PCB trace instead of a chip antenna.
This also might explain why this board gets a lot hotter than my other esp32-c3 boards - I’d put it down to having less board area, but if all the transmitter energy is being soaked into the board as well I bet that doesn’t help!
1 Like
Nice to see that the super mini can do something. I bought the same one and wanted to use it for a voice assistant, with a mic and speakers. However, it only works on the esp32 wroom, but not on the super mini. I have some ld2410 running with an esp8266. I will probably replace these with the super minis and save some space
I love ESP32-C3 super mini because their pins can be assigned to any UART, I2C, SPI, PWM… so you can solder direct to pin 3&4 as seen above picture and assign TX and RX to those pins.
Oh man this is absolutely hilarious. You need to look up “how an antenna works” lol the two sides arent suppose to connect together.
1 Like
I wouldn’t recommend using the ESP32 as it is, because to me it looks like you created a short.
The below is the only proper way you can add an external antenna to the ESP32 super mini board. Unfortunately, it requires you to have SMD soldering skills and equipment to solder the antenna shield, as the “pad” is sub-mm size and there are components right next to it.
However, soldering a 3cm (not longer, not shorter) wire on the “Wire core” pad could increase signal strength substantially.
2 Likes
I got just got bit by this. My first one worked fine but the next has no network response unless I’m literally touching the board/wire in the right place. There is evidence that a batch of these boards are defective.
You can!!! OMG Becky, look at them skills!!
Oh wait, false alarm… You’ve been able to assign gpios like that going back to esp8266 where some fearures could be assigned and its been a standard feature since esp32 first launched several years ago.
Becky’s gonna be disappointed with a false alarm…
Hi. Thanks [cyberumb15]. your Ideea was a good start for me in fixing my esp32 c3 super mini before throwing them to garbage. Now all of them work ok.
My best performace with them was with a 62.5mm wire. I’ve tried 32.2mm, 6.5mm, 124mm. With a 62.5mm it works normal… Another problem (I think), there are 2 capacitors missing. There should be 3 caps but it’s only 1…in series with the antenna. other 2 to the ground are missing but the pads are there… I didn’t bother with them because the module works fine with that wire 
