I bought the mmWave Human Detection Sensor Kit a while ago and it’s been running for over a year and working perfectly with home assistant. The other day I had to unplug it to move a plug around and now the mmwave sensor doesn’t work anymore. The esp32 is working fine and detected in home assitant and the grove temperature and humidity sensor that is plugged in is still working fine, just the mmwave sensor stopped working.
I’ve tried re-installing from ESPHome but still only the temp humidity is working. Does anyone have any ideas what else I could try to troubleshoot this? I haven’t tried reflashing the firmware yet but I’ll try that and see. Could unplugging the device kill the mmwave sensor?
No I haven’t been able to get it working since it stopped. It still works as a temperature humidity sensor in Home Assistant but the mmwave radar hasn’t worked again. I’ve taken the device completely apart and checked all connections and re-flashed the firmware. It seems like the sensor just died. I’ll eventually take it apart again and check for dead capacitors with a multimeter but I replaced it so that isn’t a high priority.
Unplugging the device should not kill it. However, power spikes can damage mmWave modules. Your ESP32 and temp sensor still work fine. That suggests the radar module likely failed. First, check if the radar board LED turns on. Next, measure voltage at the module pins. Then test UART output with a USB-TTL adapter. Also try different ESP32 GPIO pins. Some modules reset their baud rate after power loss. If there is no serial output, it is probably dead. You can build a replacement using this project: https://www.pcbway.com/project/shareproject/ESP32_DevKitC_MMWave_Sensor_LD2420_6e5e9b6d.html. The LD2420 works well with ESPHome and Home Assistant.
Something changed after a Home Assistant update. A number of users with mmwave modules have experienced this. If you can re-install the firmware the mmwave sensor will come back online and report presence sensor data. The esphome module reports its online. Once the power is removed to reposition the sensor elsewhere the esp32 module reports online, but the mmwave module reloads the firmware but after it does so, it does not output any sensor data to the esp32 module. The problem is reproducible.
Perhaps Seeed should get involved with the esphome developers to help find a fix, but I have not seen anything regarding this.
I wanted to get a couple more of theses sensors but due to the long period where the issue has not been resolved or addressed, I currently would not recommend this device to anyone.
You can refer to this community post and see for yourself when this issue actually started. The post also has a link where it was reported to their esphome developers. I can’t post a link but you can go to the Home Assistant Community website and search for MR24HPC1 Communication Issue with ESPHome.