JHEMCU F722 AIO 40A 30X30 FC FOR DJI does not work DJI goggles properly, laggy and no OSD

[Ekaterina]

HI, I recently bought "JHEMCU F722 AIO 40A 30X30 FC FOR DJI". However, DJI goggles is not working properly, laggy and no OSD. Also, DJI's display data always shows flight clock 0'00 and drone's voltage 0v. Flight control is fine.

Base drone is iFlight titan DC2 AIO with Frsky, and simply replaced an original FC/AIO with this new AIO. So, I believe my all motors, transmitter and DJI air-unit should be working, and JHEMCU board is something wrong.

There are 2 problems:
1 - Air-unit's vision is very laggy/steppy.
2 - OSD does not show up in DJI-goggles.

JHEMCU F722 AIO 40A 30x30 FC for DJI 3S-6S BLHLei_32

This is perfect for 4 inch to 5 inch lightweight racing builds. Lightweight and easy to install. With a higher ESC rating, it opens up a whole new world of possibilities. Shop online:

www.airbladeuav.com

My guess is to miss some switches, could be beta flight configurator, then FC board does not send proper data, voltage, ampiler.
If anyone knows how to fix, it would be great, thanks!

 

[droneguy]

Your air unit is in low power mode because the FC isn't telling it that is has armed. Your MSP connection is set wrong. This FC uses UART6 on the plug-in harness for MSP. Change your ports tab configuration to use UART6 for MSP and you should be fine.

 

[Ekaterina]

DroneGuy
Thanks for your help!!!

So I changed MSP like blue circle. Do I need to change red parts, or leave as it is?

 

[droneguy]

Your configuration should have column 1 (configuration/MSP) only on for USB/VCP and UART6. Turn it off for UART3. If you are using a DJI remote, then enable serial RX on UART2 as you have in the pic. everything else can be disabled.

 

[Ekaterina]

now my drone flys without laggy vision, thanks!! However, there is one problem: voltage number during flight.?

Basically when flying higher around 10-15m height, voltage drops around 13.8v gradually from the beginning of flight. Drone can still be flying, but weird. When flying 1-3m is fine. After flying height 3-4min, drone can still fly with 13.5v. My original FC/AIO is not like this. it kept good voltage when flying higher height. And when hitting 13.5v, flight time is pretty much end after flying 3-4 min, which is similar to the old FC/AIO.

Thus, my guess is :
1 - voltage number is somehow wrong, lower than actual battery's voltage. Do voltage display really change by boards???
2 - still configurator setting is wrong. (I just changed ports exactly you advised me, thus I believe it should be good.)
3 - My soldering is bad. (it should be perfect, no problem)
4 - Maybe I need to change
5 - My motors are from iFlight BNF, so do I need to adjust PID for new board??

TITAN DC2 HD Whoop - BNF

Less than 250grams included 4S 450mAh battery No Props or frame in view! Low Resonance frame construction (Less Jello, more Cinematic) DJI FPV Air Unit 720p 120fps FPV feed (record in 1080p/60fps) Butter smooth XING1404 4S Duct prop guards to protect

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In fact, when arming by transmitter, DJI goggles sometimes shows 'disarmed' message, but Drone seems to be able to fly as usual. If I really want to disappear the message, I do unplug&plug again the battery of either goggles or drone.

Do you have any ideas??

 

[droneguy]

This flight controller supports up to DSHOT 1200 but set it to (A) DSHOT 600 and BLHeli32 so it supports bidirectional Dshot so leave it on (B). You can turn off (C) the barometer, there isn't one. Your voltage scale should be 110 and current scale 100 (D)

Everything else is default so it's a good place to start and it should fly pretty good. Your altitude has nothing to do with your voltage sag. I would make sure you properly balance charge your battery to full capacity and try again.

 

[Ekaterina]

Hi, I did some flight tests.

When flying higher height, voltage still shows lower voltage than that of previous board. And even hitting voltage 13.5v, drone still can fly! Previous board would not make it with that voltage. I guess that's how this AIO board works...

Extra questions are:

1 - When using Bidirectional Dshot, I can hear only first half of startBeep sound, and Drone does not move at all by Transmitter control. Thus I just turned off. What's the benefit to use this?

2 - What's benefit to use ESC_sensor?? Maybe I could turn off to save power.

3 - Configurator shows 14.91v and ISDT shows 15.01v, so I don't think I need to change voltage scale to solve strange voltage issue...

 

[droneguy]

Hi @Ekaterina,

Sounds like you a very new to FPV drones so let's keep it simple and get you flying with a good working drone. I would suggest you only worry about tuning a little later once you have more experience and can tell the difference when flying.

1 - When using Bidirectional Dshot, I can hear only first half of startBeep sound, and Drone does not move at all by Transmitter control. Thus I just turned off. What's the benefit to use this? Your ESCs might not have the proper firmware loaded on then to support bidirectional DSHOT. It's OK not to use it. Bidirectional DSHOT is a new feature in Betaflight 4.x which lets the flight controller receive accurate RPM telemetry over each motor’s ESC signal line. It is necessary to use RPM filtering. RPM filtering is a set of notch filters on the gyro which uses the RPM telemetry data to remove motor noise withvery high precision. It basically lets you tune your drone much better. But for new pilots it's a bit complex to configure properly. If your BNF comes with it enabled and configured, great! if not, maybe don't worry about it for now. Heck, I've flown for 6 years without it so it's not essential to build your skills.

2 - What's benefit to use ESC_sensor?? Maybe I could turn off to save power.
The ESC sensors (voltage and current) provide you with the information about your voltage and current draw. The ECS send the telemetry to your FC which in turn lets you configure and see it on your goggles. It's valuable information and you should keep it enabled.

3 - Configurator shows 14.91v and ISDT shows 15.01v, so I don't think I need to change voltage scale to solve strange voltage issue...
The voltage scale for that FC should be around 110 which it is so leave it. The current scale should be 100 not 450. Are you charging your batteries to 4.2v per cell? Your fully charged voltage on 4S should be 16.8v. Fully charge your battery then check with a meter and check your scle in Betaflight so it matches.

 

[Ekaterina]

You are right, Drone God. I have only flew 11months. I started toothpick and shifted to this iFlight BNF air-unit. When some parts are broken, it's time to learn new knowledge for me.
1 - Ok, default setting does not work , involving RPM filtering and other settings. I have no idea. I just turn it off.
2 - okay, I keep it ON
3 - yes, 14.9v is battery after flight. Full charged battery shows 16.6v in ISDT and 16.54v in betaFlight.

Flight is is very stable with the above setting, but I got FS! twice yesterday in the same spot. Probably interfere radio is in the sky. How often do you lose TX or RX in general?

 

[droneguy]

I use crossfire for my control link so I never fail safe, but any transmitter with 100mW or more should have decent range. What output power are you set to?
It looks like you are using the DJI radio with the goggles. Go into the Goggles’ menu, under Settings => Device, you should be able to select 700mW for your output power. Also, by enabling Power Limit, it will give you some protection against overheat when the Air Unit is sitting on the ground.

Depending on the laws in you regions (mandatory disclaimer), you could also enable the 1200mW hack to get even more range. By default, the maximum output power of the DJI FPV System is limited to 700mW if you are on FCC mode. With 1200mW you will gain roughly 30% more range, and it gives you better signal penetration. The hack only orks if you are operating if FCC mode.

ENABLE FCc mode

• Take the micro SD Card out of the Air Unit
• Create a text file on the root directory, name it naco(so the file name and extension becomes naco.txt)
• Write 1 in the text file (which means FCC mode for USA)
• Insert SD card in the Air Unit
• Power up goggles, and then Air Unit

Enable 1200mW hack

• Create a .txt file, name it naco_pwr
• Type pwr_2 inside the text file
• Save and close
• Copy naco_pwr.txt to an SD card
• Power on Goggles and Air Unit, WAIT until you see image from camera
• Put SD card in DJI goggles
• Restart Goggles

Just because you can use 1200mW doesn't mean you always should either. I run min at 700mW or 1000mW most of the time with crazy range d penetration. Running high power in hot weather can damage the air unit. Don't leave you quad powered on for long times when you are not flying.

 

[Ekaterina]

I think DJI goggles are always fine. For instance, one of two Antennas is already broken, and last time I flew the drone even though another Antenna was disconnected. However, the goggles had received a certain vision. That's why I did not notice the unplugged by chance.

For transmitter, I am using FrSky X-Lite, and FrSky XM+. I can usually fly 200m-250m away. But sometimes it becomes FS! , due to transmitter signal is lost, by maybe other interfered radios, I guess.

By the way, I currently live in Canada.
So far, I've never seen people play FPV-drones here, except my friends, lol

 

[droneguy]

The FrSky X-Lite is a good radio. It has a built in antenna so the range with XM+ in best of conditions will 500-600m. With interference probably half that range. You can add an antenna to the FrSky X-Lite by popping off the round button cover on top and connecting an SMA 2.4GHz antenna. It may give you 25-30% more range. You DJI antennas are pretty important so you should replace them especially since the goggles not only receives, but transmits back to the air unit.

I'm also in Canada and there are alot of FPV pilots but they are all indoors at the moment due to the cold weather.