Support for HLK-LD2412

[pkkrusty]

LD2412 is an improved version of LD2410 with better range and wider FOV. Similar price point. I have a few on order and will see how compatible they are with the LD2410 driver.

But wanted to preemptively ask for the LD2410 driver to add support for 2412. (I know PRs are welcome from anyone, but Theo wrote the code for 2410...)

Esphome community is actively working on support link

[Staars]

Nice finding. I received one too now and started to adapt the old BLE driver of the LD2410.

It is a little bit different now, but finally I got notifications from the sensor:

18:23:56.872 BLE: start LD2412 driver
18:23:56.874 BLE: Connection Ctx created
18:23:56.876 BLE: discover services
18:23:58.773 LD2: Start config mode
18:23:58.919 LD2: Sensor ACK
18:23:59.773 LD2: Request FW
18:24:00.119 LD2: Firmware version V1.36.36080523
18:24:00.774 LD2: Stop config mode
18:24:00.870 bytes('FDFCFBFA0400FE01000004030201')

The data format has changed according to the new number of gates, but most of the commands are still there and working.

[Staars]

I have worked my way through the various documents, that can be found on HLK's website and in some GitHub repos.

In theory it would be possible to write one (Berry) driver, that can work with most sensors of the LD24-family, but there are a lot of "if's" and "but's".

There are definitely missing commands in the official documentation, that would have to be reverse engineerd (that is an unnessecary waste of time!)

The received payload in the case of the LD2412 does not match the documentation completely. That could be attributed to the fact, that I use BLE and not serial, but it could also mean, that changes in the sensor firmware are responsible for that. In the case of the LD2410 this did definitely happen.

AFAIK there is no API to simply get a sensor/hardware ID, so that I know if it is a LD2410/11/12 or another type. This would have been really nice for a universal driver approach. It might be possible to infer this via the firmware info or something like that, but again - a waste of development time.

So summarized: I am almost sure, that it is technically possible to support "everything", but at the moment it looks like an annoying task due to the lack of documentation. I have my doubts, that other drivers out there, will work with every firmware version (mainly of the very common LD2410) as supposed.

[Staars]

Just to answer myself to some extent...

I started a second driver in Berry for serial communication and can confirm for the LD2412, that the payload seems to be equal for BLE and serial. Thus in my my case both do not match the documentation (in engineering mode).

But besides the idea is growing in me to try to have a common LD24xx driver, that infers the connected sensor via firmware type and firmware version (this command should be supported by every sensor of the family) and then instantiates the fitting sensor class, that has to implement some mandatory functions.

[Staars]

https://github.com/Staars/berry-examples/blob/main/serial/serial_ld24xx.be
This is just a proof of concept, it is not even in alpha state.

If someone wants to give it a try there is basically only one question from me at the moment. Does the driver detect the correct sensor type?

var ld2 = LD2(3,4,115200) # or 256000 baud in line 639 must be changed according to the pin setup LD2(rapine,txpin,baud).

[Staars]

As I have the LD2420 connected to my test ESP, I did continue with this radar sensor.
The ESPHome driver is pretty well documented and the resulting data is in line with what I receive here.

I updated the driver from above and it works here for me with auto detection of the LD2420, outputting the full gate energies (like the engineering mode on the other sensors):
"LD2420":{"presence":1,"range":134,"gates":[11817,2900,185,68,18,41,32,25,17,20,10,13,10,13,13,0]}

I will try my luck with the LD2412 next, but I expect problems with unknown/not documented parts of the payload with the firmware version of my LD2412.

[Staars]

Finally most of the docs make sense to me.
I think, I have the engineering mode working - producing a JSON like that:
"LD2412":{"distance":[0,40],"energy":[0,100],"moving_energies":[0, 2, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0],"static_energies":[0, 100, 100, 100, 100, 100, 100, 100, 100, 13, 78, 70, 64],"light":11}.

(LD2412 connected via Bluetooth)