ESP32-C3 SuperMini antenna modification • Hacker News Board

Re: ESP32-C3 SuperMini antenna modification

#21

Post by minimaltom » Mon, Aug 03, 2026, 4:09 PM UTC

DarkStar851 wrote: post #20

minimaltom wrote: post #12

Silver-coated wire? I don't have that lying around.

Paperclip has worked fine in my experience. I've got a bunch of these and the stock antenna really is just awful.

Paperclips can be very difficult to obtain sometimes :P (have you seen smiling friends?)

Re: ESP32-C3 SuperMini antenna modification

#22

Post by flossEveryday » Wed, Aug 05, 2026, 5:23 PM UTC

TGower wrote: post #9

bArray wrote: post #2

Antenna design is a dark art, I like simple hacks like this. > The two parts of the antenna are intentionally designed to create an omnidirectional radiation pattern without a pronounced directionality. I worked on a project a while back to try to utilize this to detect the arrival direction of WiFi signals approximately based on received strength. Do this for enough base stations and you have a very crude positionin…

I'm doing something similar, using the directionality of the antenna to turn an ESP32 into a high RPM gyroscope for use in a combat robot. Standard gyro chips top out well under 1000 RPM, and are much more expensive than an ESP32 board, plus the ESP can serve as the radio control link and brain of the bot at the same time.

cool idea. care to share more? my thought would be continuously measuring antenna impedance over time, and looking for a peak in this signal's spectrum near the rotation frequency. could also try with a photodiode (+ optional light source, or use ambient light) (this would be similar to an optical computer mouse), which i guess could be more directional, and thus give a stronger signal

Re: ESP32-C3 SuperMini antenna modification

#23

Post by TGower » Sun, Aug 09, 2026, 2:42 PM UTC

flossEveryday wrote: post #22

TGower wrote: post #9

Earlier quoted context omitted.

I'm doing something similar, using the directionality of the antenna to turn an ESP32 into a high RPM gyroscope for use in a combat robot. Standard gyro chips top out well under 1000 RPM, and are much more expensive than an ESP32 board, plus the ESP can serve as the radio control link and brain of the bot at the same time.

cool idea. care to share more? my thought would be continuously measuring antenna impedance over time, and looking for a peak in this signal's spectrum near the rotation frequency. could also try with a photodiode (+ optional light source, or use ambient light) (this would be similar to an optical computer mouse), which i guess could be more directional, and thus give a stronger signal

Combat robots are more like RC cars than autonomous robots, the driver stays in control of the bot over a radio link. I use ESP-NOW, and get about 6000 packets per second from the transmitter to the ESP32 in the box, and each comes with radio link stats, signal strength and Channel State Information. Using autocorrelation on the signal strength gives you the rotation period, and using that you can establish a Phase Locked Loop to remove the drift of integrating rotation speed to get absolute rotation angle.