LD2420 Radar Sensor Module 24GHz ISM Human Body Micromotion Millimeter Wave Radar Sensor Module AIOT Smart Home 8M 3.3V 50A

I've used two of these and they work well with home assistant and esphome. The recognized movement at a fair distance, say 30ft. Lots of different options to play with in the settings.

First - if you want to know how to hook this up and get started quickly, search for ld2420 on esphome's site. Not only will you get access to the code to see an example, but there's a very nice module page that describes all the CORRECT hookups, in English without any false/misleading information. The problem with this unit is, simply put, that two different versions exist with the same look and feel and depending on what version, the hookup is very different. The original/old version (< v1.5.3) is most likely what you'll find when googling and it will absolutely NOT work - wrong baud rate and wrong TX pins. The unit I got was the newer (>= v1.5.3) version. This means OT1 is the TX and not OT2 and the baud rate on this unit is only 115200 - not the weird 256000 for the old version. I've found no way to tell which version the unit is by looking at it. Only once you ARE connected can you query the firmware version, and then know how to hook up the wires, and well - you get it. It's a mess. Once hooked up to an old ESP32 using TX2/RX2 for basic uart functionality I finally got the results I wanted, the unit was working. Until then I spent days talking with the vendor - who was VERY responsive but only offered a full Chinese language only documentation. Nothing for the country they sold this in. For this reason I would suggest finding another vendor - but at least you know and with the external documentation like that on esphome.io you'll make this work. This site covers the parameters fine. To understand how this unit works under the covers, you seem to have to learn chinglish as you auto-translate documents in Chinese.

Worked perfect in my project, but it was hard to find an english version of the software for it.

Beautiful, all i can say

I bought several for a project and they work perfectly. The software was tricky to track down but I found everything I need. Google is your friend.