In this tutorial I will show you how to setup HDZero in a Betaflight FPV drone from scratch, including connection to the flight controller, Betaflight OSD configuration, SmartAudio setup, firmware update and explaining the options in the menu.
How to Update HDZero Firmware
I recommend updating your VTX and VRX to the latest firmware for bug fixes and new features. Cameras don’t need to be updated at the moment. It’s best to update your VTX before mounting it in your frame, as it’s easier to access the update port.
Download firmware: https://www.hd-zero.com/document
Get the latest update, the zip file includes firmware for all the existing HDZero compatible VRX, VTX’s and FPV goggles.
The process takes around 10 mins, so make sure the battery you use to power the VRX is charged to avoid running flat during the update.
Flashing the wrong firmware could brick/damage your device. If you flashed the wrong firmware, there’s a recovery process in the manual you could try to fix it.
How to Flash HDZero VRX
The firmware files (HDZero_RX.bin, HDZero_VA.bin and HDZero.bin) will be deleted from SD card after updating. If these files are gone, it’s a good indication that the firmware update has completed. But for whatever reason you want to keep the firmware files after update, for example you have multiple VRX to update, then simply create an empty text file on the same directory and name it “DONOTREMOVE.txt”.
SD Card not recognised? Try to format it inside the goggles. If you format it on your computer, choose FAT32 format and set Allocation Unit size to 4096 bytes.
If you power off the VRX during firmware flashing, you could brick the VRX, and it won’t boot up anymore.
It comes with an XT60 power cable with two outputs, it allows you to power both your goggles and the VRX from the same battery. However, make sure your goggles can support the same voltage you are using to power the VRX, because the power cable has no voltage regulator built-in, both outputs are the same voltage as the input. Some older goggles only support up to 3S, if you feed them 6S you will fry them.
The VRX supports 2S to 6S, so it’s pretty flexible.
VRX Antenna Choices
Antennas are not included. Not sure what to buy?
You should mount antennas on all 4 SMA connectors to maximize its potential. Choose antenna according to your flying environment and application.
Use 5.8GHz antennas. You can use either right-hand circular polarized (RHCP), or left-hand circular polarized (LHCP) as long as they match the one you are using on the drone.
According to HDZero manual, for best results, you should use matching antennas for the two top SMA connectors, and matching antennas for the two on the sides.
Connecting Camera to VTX
Note that the MIPI cable that connects the camera to the VTX needs to be purchased separately, it’s not included when you buy the camera or VTX.
It comes in different lengths so make sure you measure how long is needed before purchasing. Lengths available are: 4cm 8cm, 12cm, 25cm. Note that the DJI MIPI cable doesn’t work with HDZero because aparently DJI’s are not standard size MIPI connectors.
Get the longer cable than you need! It’s better be too long than not long enough! 12cm should be ok for most 5″ frames, but for some with long body it might not if you are mounting the VTX at the very back. Double check.
The MIPI connector can only fit one way, press very gently and do not force it. You can secure it with the provided zip tie or metal plate.
VTX / FC Wiring
There are only 4 wires you need to connect between the FC and VTX: VCC, GND, TX1 and RX1.
VCC is the power, GND is ground, TX1 and RX1 connects to any spare UART on the flight controller.
If you want to setup SmartAudio too, you will need 1 extra wire to connect the SA pad on the VTX to an RX pad of another spare UART. I personally recommend setting up SmartAudio, it’s useful.
Although some of these HDZero VTX supports up to 6S input voltage, I strongly recommend powering it via a BEC (built-in voltage regulator on your FC), for example 8V-12V, and not directly from the LiPo. Crashing or the motors getting obstructed can cause a massive voltage spike in the power system and can burn out the VTX. Powering the VTX via a BEC can reduce the risk of that.
Mounting VTX in the Drone
It’s important that you check if your frame can fit the HDZero VTX. For example the Race V2 VTX, although it has 20x20mm mounting holes, it’s almost as large as a 30x30mm board so it might not fit in some frames designed for the DJI Vista which also uses 20x20mm mounting.
Before powering on the VTX, make sure to attach the antenna or it could overheat very quickly and get damaged.
The U.FL connector is probably one of the weakest points of any HDZero VTX, it can be ripped off when the antenna pulls on that pad. Therefore you should use zip tie or the provided metal plate to secure the U.FL connector in place.
Changing VRX Settings
There are two modes, Video mode and Setup mode. In video mode, HDMI outputs live video, while setup mode outputs the system menu with lots of settings.
To switch between Video mode and Setup mode, push the wheel to the left and hold for around 3 seconds, then release.
In Setup mode, use the wheel button to navigate and push down the button for confirmation, push the wheel to the left and hold to return to the previous menu.
How to Record Video (DVR)
By default, the DVR automatically starts recording if there is video signal from the quad. It can be set to manual start recording in the menu.
An 8GB-32GB SD card is recommended by HDZero. I’m using a SanDisk Ultra 32GB and it works well so far.
First of all, format your SD card inside the module to avoid any potential format issues (the format option is in the system menu). If you must format the SD card on your computer, choose FAT32 and Allocation Unit size to 4096 bytes (in windows).
- DVR video files resolution: 1280x720p 60FPS
- Bitrate: 18Mbps with TS format, 12Mbps with MOV format, format is optional in system menu
One minute of recording in TS format is around 130MB, so a 32GB card can store around 240 minutes of video (rough estimation). MOV video format takes around 30% less space but also lower in bitrate.
TS format is tolerant of being cut off. In other words, if the video file is suddenly cut off (say, by pulling power before stopping recording), it wont be corrupted, and will still play. It’s not about quality at all, really. It’s about making sure you don’t lose footage. The MOV option is the same encoding, but the start of the file contains an index to make seeking easier. When you stop recording, the DVR writing the file goes back and updates the index. If you pull power, the index isn’t written, so the file needs to be repaired, which may or may not work.
I think for most people, the MOV format is better because many popular video editors don’t support TS format and you need to convert it to MP4 or MOV first. MOV is just easier to work with.
When SD card is full, recording will stop but it won’t affect the live video. Switching to setup mode in the module will stop the recording also, and switching back to video mode will start the recording again but in a new video file.
The HDZero Goggles support better DVR (h.265 at 25mbps) and they allow you to pick either TS or MP4, both are the same quality, but MP4 is better in compatibility with many video editors.
Here’s a troubleshooting guide and frequently asked questions.
VRX Not Booting Up After Update
It probably needs to be re-flashed in bootloader mode. Here’s how:
Power off VRX, get the correct firmware on an SD card and insert it in the VRX module.
Move the switch to Bottom position.
Power on VRX module, the red LED will light up, wait for it to turn off, on, and then off again (it could take over 10 min to complete).
Power off, and move the switch to TOP position.
That should fix it.
First thing to check is if you connected the VRX to the goggles correctly, can you see the VRX menu? If you can then the problem is probably on the VTX side.
Check if the camera is connected to the VTX properly and any sign of damage on the MIPI cable/connectors.
Try updating the VTX and VRX to the latest firmware.
Check if the VTX is getting enough power, maybe the BEC you are using doesn’t supply enough voltage or current. Check with a multimeter, and test the VTX by powering it directly from a LiPo battery. The red LED might give you a hint, it should be bright red when powered, if it’s dim and flickering that could be a sign of not getting enough power.
If the Blue LED flashing about once every second, chances are it’s not detecting the camera, or it has the wrong firmware. Try flashing the correct firmware again. If that doesn’t fix it, try a different camera, or put that camera on a different VTX.
Also make sure you have the HDMI output setting correctly, the options are 720p and 1080p. On certain goggles such as the Skyzone you need 1080p otherwise color might not look right. But on Orqa only 720p works.
Unsupported HDMI Input
The issue could be wrong resolution option (HDMI output in menu). Toggle between 720p/1080p and see which one works for your goggles. If you can’t do it in the goggles, connect the module to your computer monitor with HDMI input, most monitors should support both 720p and 1080p.
OSD Not Working
Make sure firmware are updated on both VRX and VTX.
Check if you are using the right UART in the ports tab and that’s indeed connected to your VTX, remember the port number you enter in CLI has to be the UART number subtracted by 1, for example UART5 is 4, UART2 is 1, etc.
The TX pin should go to RX pin, and RX to TX. Do not use softserial. Make sure you have configured MSP display port correctly.