30KM 1080p 60fps 150ms - SIYI HM30 Full HD Digital Video Link Telemetry Radio System

lorbass · February 16, 2022, 12:04pm

Now, I’m confused.
I made a succesful Testflight with PPM at the RC Signal Input of the HM30 Ground Unit.
(Teacher Output of the Taranis TX via cable)

lorbass · February 16, 2022, 12:41pm

May be this Video from SIYI helps your question:

This setup was earlier used for Diversity.

Looks at the Battery Symbol. After 20 min and 4000 mAh still at 100%

norim · February 16, 2022, 5:49pm

I have the same problem with battery status - always 100% Anyone have a solution for that ?

lorbass · February 16, 2022, 6:10pm

I’ve not recorded my Screen and don’t remembert how it was at my 2 test flights.
But may be it has to do with the Param BATT_CAPACITY in the Flightcontroller.
(Config/Full Parameter List)
If this is not set, the remaining capacity can’t be calculated.
Did you set this Param?

SIYI · February 17, 2022, 2:53am

Sorry, my mistake.
On the air unit S.Bus port there is only S.Bus. On the ground unit, all three inputs are available (S.Bus/PPM/UART) @Risto

SIYI · February 17, 2022, 2:58am

I assume you are saying that only the battery percentage does not change, but the current and voltage changes normally, right?

Risto · February 17, 2022, 7:13am

Awesome, thank you Frank. How to use the RC signal input port of the ground unit in UART mode (that was my original question) - what protocol to use to send the channel data to the ground unit?

Also my second question about the two antenna ports on the ground unit (the same question goes also to air unit) is yet unanswered - does HM30 use diversity or is one antenna port for receive only and the other antenna port for transmit only? Thanks!

norim · February 17, 2022, 9:06am

Parameters are ok they works on other telemetry. But I will check this.

SIYI · February 17, 2022, 11:28am

It is diversity, both ports receives and transmits

Risto · February 17, 2022, 11:53am

Thank you!
If this means that both antenna ports (on ground unit and on air unit as well) are used to transmit and receive the same data on the same frequency band, for an airplane, that banks during turns, to my knowledge, it would make sense to mount the antennas in the ground unit and on air unit in a V-shape, as @Mohammad_Adib posted above on January 11th:
grafik

On January 12th you replied Mohammad_Adib with:

I wonder, what is the technical reason for this that you recommend against a V-shape?

Also, could you please shed some light to the RC signal input via UART - it is still unknown what protocol the HM30 ground unit expects for this.

Bersan_Zeynep_SODER · February 17, 2022, 12:20pm

Hi Frank,

There are a few details I would like to learn about the SIYI HM30 Full HD Digital Video Link product.

Is the product called HM30 used as both bidirectional receiver and the transmitter? or is it one-way?
Is there a single point of failure in the product?
Does the product support mesh networking?
How many devices does the air unit support if we want to use it as a multi-vehicle?

Best Regards

SIYI · February 18, 2022, 8:58am

What I suggested was based on massive flight tests made by our team, the V-shape is also ok which is easier to mount I think. Please make sure the two antennas are mounted at least 5 cm away from each other. And please try to not let the wings block transmission during flight.

You can refer to the connection between an OpenTX transmitter and the FM30 radio module as an example.

SIYI · February 18, 2022, 9:01am

Hi Bersan,

Thanks for your post.

Both bidirectional

Sorry, I do not get this quesiton, please try to explain a little more.

As far as I know, there is similar feature in development.

With the standard product, one ground unit bind to one air unit at the same time. It can bind to multiple air units in turns in the future.
With the Dual Link combo, two ground units can bind to the same air unit at the same time.
The ground unit does not bind to multiple air units simultaneously.

Risto · February 18, 2022, 10:58am

Thank you Frank - this helps a lot. I had a look at FM30 manual:

Likely the S.PORT is meant, that is used for FM30 communication in OpenTX/EdgeTX in Multi-Protocol-Module mode:

For testing this out,
a) should the S.PORT pin of JR-bay be wired to S.PORT pin of HM30 ground unit RC input and the S.BUS/PPM/UART pin remains unconnected, or

b) does the CPPM pin of JR-bay go to HM30 ground unit PPM/SBUS/UART pin and S.PORT pin to HM S.PORT - thus HM30 and the radio will be connected via 2 data lines, or

c) S.PORT pin of JR-bay should be wired to HM30 ground unit PPM/SBUS/UART pin and the JR-bay CPPM pin remains unconnected?

Risto · February 18, 2022, 2:10pm

Post updated.
I tested HM30 in UART RC signal input mode with RadioMaster TX16S loaded with OpenTX v2.3.14 and can report success.

One needs to connect 3-wires between the JR-bay of the radio and the HM30 ground unit RC signal input port for the UART communication mode of the HM30 ground unit to work:

HM30 RC signal input port PPM/S.BUS/UART pin to JR-Bay CPPM pin,
HM30 RC signal input port S.PORT pin to JR-bay SPORT pin and
GND of JR-Bay to RC signal input GND

The original cable for the RC signal input port delivered with HM30 unfortunately does not have S.PORT pin included in the 4-pin JST GH connector, so one needs to crimp a custom cable for this.

For the interested I attach a Saleae Logic v2 capture of the PPM/S.BUS and S.PORT pins from cold start of HM30 ground unit and TX16S with OTX 2.3.14: HM30_TX16S_JR_Bay_OTX2.3.14.sal.zip (28.9 KB)
In the second logic analyzer trace with connected air unit, one can see in S.Port stream RSSI (dataId of telegram being 0xF101) packets with values 96 and 97 (32-bit values): HM30_TX16S_JR_Bay_OTX2.3.14_connected_air_unit.sal.zip (17.9 KB)

@SIYI May I suggest “MULTI” or “MPM” instead of “UART” for the third option in the GUI and in the documentation for the HM30 GU RC signal input, which would in my opinion make it more intuitive of what protocol is expected here, thus: “PPM/S.BUS/MULTI” or “PPM/S.BUS/MPM” instead of “PPM/S.BUS/UART”. It would be neat if the docu would also list that the S.PORT pin of the 4-pin port needs to be wired up as well for the third option to properly work. Thanks!

Yuri_Rage · February 18, 2022, 8:55pm

Very exciting news. I look forward to trying similar with my own OpenTX transmitter. Thank you for the data plots, as well!

lorbass · February 19, 2022, 7:01am

I can confirme, the battery percentage does not change. The “remaining battery” indication change
at the MissionPlanner with telemetry. Voltage and current are correct.

SIYI · February 19, 2022, 9:04am

Thanks for confirming.
Is it also possible to confirm if the battery percentage is correct in QGroundControl?

Risto · February 19, 2022, 11:13am

Just tried with EdgeTX (v2.7.0-dev) and XN297DU protocol in AUTO subprotocol mode seems to work with HM30:

(if you wonder about the funky gimbals on that TX16S in the pic above - they are the 3Dconnexion SpaceMouse modules, with 6D (6 channels) each: https://3dconnexion.com/us/product/spacemouse-module/ )

lorbass · February 19, 2022, 2:28pm

Yes, in QGroundControl the percentage on the middle,top of the screen shows correct values.