Integration of esp32c3 super mini with ld2410 and ld2420 presence detectors

ESPHome
1

After looking for how to configure the HLK-LD2410 and HLK-LD2420 presence detectors and seeing that there was little information, I started to carry out tests to try to configure them, from these tests I got these results:

I have managed to configure both, and if you look at the YAML files you will see that you have to change pins 20 and 21 depending on the sensor you are using, I don’t know if it is because of a bad definition of the pins on the boards I have or because they are poorly silkscreened, the fact is that they both work like this.

I have also made two sketches in Fritzing to put them into operation, the PCB has been designed, I currently have both of them working.

Both have a HLK-PM01 power supply of 5V and 0.6A and are powered at 220V alternating current, as I intend to place them attached to the ceilings I have and draw the power from these.

You can find the YAML configuration and diagrams at the following link:
https://github.com/JVRMTS/Detectores__Presencia_Esp32C_SuperMini_HomeAssistant

Excuse my English, I’m using a translator

2

This doesn’t make sense to me.
Your wiring is wrong: You are connecting to OT1, where you should connect to OT2
grafik

grafik
grafik878×1027 182 KB

(Source: HLK-LD2420/HLK-LD2420-Product Manual V1.2.pdf at 95ca950e33908ec364c3764a7c7a780ec43ee308 · soubhik-khan/HLK-LD2420 · GitHub)

3

What you say is correct if the device firmware is less than 1.5.3 I am using version 1.6.1

Imagen de WhatsApp 2024-11-27 a las 10.09.44_817999b3
Imagen de WhatsApp 2024-11-27 a las 10.09.44_817999b31480×1032 197 KB

4

a3e0efe9-3984-443b-b8ea-b121acc36666
a3e0efe9-3984-443b-b8ea-b121acc366661480×1032 181 KB

14ddf1af-cc1f-412d-9e4a-ba2fa2399ec9
14ddf1af-cc1f-412d-9e4a-ba2fa2399ec91480×1032 148 KB

5

Since the 2025.7.2 update, ESPHOME stopped working if updated above that version of ESPHOME. For it to work, with versions equal to or higher than that, you have to change the pins to which the HLK-LD2024 is connected - tx_pin: GPIO07 and rx_pin: GPIO06. With the old configuration, it caused problems with the USB port.

7

Can you confirm that it’s working with this configuration?

Because (for the life of me) I can’t get it to work. Works fine on a regular ESP32 dev board but the c3 SM is not working for me.

Same with the LD2410, doesn’t work on the C3 SM but on the regular one

8

I ran into the same problem with the LD2420 not initializing after flashing.

After a long wild goose chase, the thing that actually solved it was to assign the UART tx/rx pins to something other than the ESP32 pinout tx/rx pins.

uart:
  id: ld_uart
  # tx_pin: GPIO43 <-- DO NOT USE THESE DEFAULT PINS ON AN ESP32S3
  # rx_pin: GPIO44 <-- DO NOT USE THESE DEFAULT PINS ON AN ESP32S3
  tx_pin: GPIO08
  rx_pin: GPIO09
  baud_rate: 115200
  parity: NONE
  stop_bits: 1

Things that were suggested on this forum and Reddit that did not work:

  • Power cycling after flashing
  • Switching tx/rx cables
  • Setting baud: 0 for logging
  • Powering from a standalone power supply
  • Using the arduino framework instead of esp-idf

It was unclear to me that this would work, as in my case my ESP32S3 pinout doesn’t show that GPIO08/09 are UART pins. But as soon as I changed the pins to these unused ones, my LD2420 was able to communicate with my ESP32S3, and I was able to still use the logger.

It appears that you can choose any two unused GPIO pins and set them to tx/rx, but you cannot use the default tx/rx pins.

1 Like