How to Setup Walksnail Avatar Digital HD FPV System

How To Setup Walksnail Avatar Digital Hd Fpv System

In this tutorial I will show you how to setup Walksnail Avatar FPV System with Betaflight. I will cover how to wire and install the VTX in an FPV drone, how to pair the Air Unit to the FPV goggles, explain all the video settings and how to use the system.

FPV Goggles

The Fatshark Dominator HD and Walksnail Avatar are basically the same goggles, just different in colour, hence the firmware are compatible too.

Goggles Antennas

Users have been reporting mixed results in performance with the stock antennas that come with the Avatar Goggles (bad range and poor signal quality). I got the Fatshark version and they didn’t come with any antennas so I am not able to verify that claim. But it’s recommended to replace them with aftermarket antennas as soon as you get the goggles.

The Walksnail Avatar system work ok with just four onmi antennas, but if you have the budget it’s recommended to use a combination of onmi antennas and patch antennas. The patch antennas allow you to get better penetration and range in front of you, and the onmi antennas provide decent signal reception all around you. To really push range you can use only directional antennas on all four RP-SMA connectors as long as your antennas are always pointing at the model.

The Avatar goggles use RP-SMA connectors so antennas for the DJI FPV Goggles are also compatible (except the dual band ones). Make sure you get only LHCP or RHCP antennas for your system and don’t mix them.

VTX Antennas

Here is a list of antennas for the Avatar VTX. Any 5.8GHz antenna with a UFL connector should work, but make sure to get only LHCP or RHCP (same as your goggles antenna) and don’t mix them.

How To Use Avatar/Fatshark Goggles

Powering Goggles

To power the goggles, you can use any 2S to 5S LiPo or Li-ion battery (7-21V), C rating doesn’t matter as it doesn’t draw many amps. DO NOT use 6S! You will damage your goggles.

Power consumption:

25mw 0.44A@16V (7.04W)
700mW 0.46A@16V (7.36W), 0.56A@13V (7.28W)
1200mW 0.48A@16V (7.68W)

Personally I just use an old 4S LiPo from my FPV drones (e.g. 4S 1500mah), that should provide just over 3 hours of battery life. Or you can just get any cheap and basic 2S to 5S battery packs, pick the biggest capacity you can afford and carry.

You don’t get any form of voltage alarm until voltage drops below certain level:

For 4S lipo. the voltage reading turns red below 14V (3.5V/cell)
For 3S, it turns red at 10.5V (3.5V/cell)
For 2S it’s 7V (3.5V/cell)

Below 5V the goggles start to read low of the input voltage by about 0.3V.

At 4.9V the latency and bitrate numbers at the bottom starts to spike, but still getting image from camera.

At 4.7V the goggles just shuts down, black screen.

There’s no beeping whatsoever when voltage runs low (I turned on low voltage and beeping volume at max), so you must pay attention to the input voltage at the bottom from time to time.

Attaching Antennas

The goggles transmit signal as soon as you power it on, so make sure to attach the antennas before powering on or the transmitter inside the goggle can overheat and cause damage.

You can use all onmi antennas for the best coverage around you (best for racing and flying with many others), or all directional antennas if you want the best possible range, or mix both onmi and directional antennas.

If you are using a directional antennas (such as a patch), make sure it’s mounted to the top left connector (with the lenses facing away from you as shown in the below image), that’s the only connector that receives and transmits data at the same time. All other connectors only receive data.

You can use either LHCP or RHCP antennas, there’s no different in performance. However, make sure you only use LHCP on on your goggles and the drones, or only RHCP on your goggles and drones, but DO NOT mix them or you will get a huge performance penalty.

As soon as you power up, the goggles will start transmitting at channel 8 (5839MHz) until it establishes a connection with the Air Unit, then it will switch to the previous channel you set it to. So if you are flying with other people, make sure they aren’t using a channel near 5839MHz or you could interfere with them. Or just wait until they land, don’t be that annoying guy 🙂

Buttons

Press DVR button to start recording video to the SD card. Press the joystick to enter system menu, exit with the Back button or wait 10 seconds the menu will disappear.

SD Cards

The SD card slot for DVR recording is located above the center of the lenses.

Make sure to format the SD card inside the goggles, by going to Settings > Record Set > Format SD Card.

Connecting Air Unit to FC

The Avatar Air Unit can be powered from 6V-25.2V according to the specs, which means you can power it directly from a 2S, 3S, 4S, 5S or 6S LiPo battery. However I’d recommend powering it from a BEC on the FC instead (e.g. 8V, 9V, 12V voltage outputs). That’s because voltage spikes and ripples from ESC could damage the Air Unit (same way it could damage analogue VTX). If you power it directly from a 6S Lipo, it is recommended to install a low ESR capacitor at the battery input, a 50V 470uF as a minimum, 1000uF are recommended.

If you are using a BEC / voltage regulator to power the Air Unit, make sure it can supply enough current. Max power consumption of the VTX is roughly 4.5W at 1200mW, the current requirement changes under different input voltage:

9V => 0.50A
12V => 0.38A
16V=> 0.29A

How to mount the VTX in the frame – most frames only have either 20x20mm or 30.5×30.5mm mounting for the VTX. However the Avatar VTX has 25.5×25.5mm holes, so you might need to get a 3D printed adapter like this: https://www.thingiverse.com/thing:5466198. Or you could just use double sided foam tape and zip tie.

The provided camera cable is 14cm which should be long enough even when mounting the VTX at the back of the frame, but double check before mounting it to avoid surprises.

Before powering up the Air Unit, make sure the antennas are attached otherwise it could overheat and cause irreversible damage. Also install the metal bar properly to secure the U.FL connectors so they don’t come off in crashes.

Pairing Air Unit to Goggles

Power on VTX and Goggles, wait for VTX’s green light to start blinking, and the home screen appears in the goggles.

Press the link button (aka bind button) on the VTX, LED should turn solid red. Then also press the link button on the goggles, it should start beeping slowly.

It should only take a few seconds to bind.

After the pairing is successful, the LED on the VTX should turn solid green, and the goggles beeping should stop. You should get an image in the goggles.

If the goggles and VTX aren’t on the same firmware version, you will get a warning every time you power up your devices. You can just skip it but it can be annoying in the long run.

You can select channels and adjust system settings by pressing the joystick button.

Choosing a channel

Avoid flying on Channel 8 (CHP), it’s the public channel which everyone jumps to when they power up the Avatar goggles.

When you first power on, don’t rush to select a channel, check out the channel list and see which ones have green bar, avoid red/black bars as that means somebody is on that channel. If you are flying alone, channel 7 is usually the best as it’s the furtherest away from WiFi interference.

Settings Explained

Press the joystick button, scroll over to Settings.

Transmit Power: there were stability issues with 1000mW and 1200mW output power reported back in August (they don’t necessary give you better performance and might cause stuttering or poor image quality), and it’s recommended to stick with 700mW for now until it’s fixed (check future firmware release notes).

When flying with other people, 200mW is a good compromise, and select Standard Bitrate to use less bandwidth.

If you do not wire the Air Unit to the flight controller via UART (TX and RX connections), you should disable Standby Mode (otherwise just leave it on). When the drone is not armed, the Air Unit is supposed to stay in Standby mode and it will only output 25mW regardless the output power setting to keep the Air Unit temperature low. It only turns off Standby Mode when you arm the quad, and when the Air Unit isn’t connected to the flight controller it can’t detect the arming.

Best Image Quality Settings

During the day I found I need to set EV to +0.3 otherwise it’s just a bit too dark (Camera settings)
1080p: slightly better image quality than 720p (sharper, more detail, but hardly noticeable only when zoomed in) but definitely gives you higher latency (10-12ms higher), below are some side by side image comparison, decide for yourself
High Bitrate (50Mbps): again it’s not universally believed to be better than Standard (25Mbps), and does not perform as stable, it might still need a bit more work on the firmware side. When using high bitrate you will only have 3 channels available instead of 8 as it uses double the bandwidth, makes it less friendly when flying with other people

Lowest Latency Settings

These are the settings recommended for normal flights, it offers the lowest latency and most stable performance.

720p
High frame rate
Standard bitrate/ High bitrate: try both and see which one works better for you, use standard bitrate when flying with other people
set EV to +0.3

Preflight Checks

Check the bitrate and latency figures before take off, make sure they are in the normal range. Typically the latency should be rock solid around 25-40ms and the bit rate should be either 50Mbps or 25Mbps depending on the bitrate setting.

If you see latency jumping way above 100ms, or the bitrate well below 25Mbps, DO NOT take off, check the antennas (maybe broken or forgot to attach one) and if there is any interference nearby (maybe anther drone powered on?). The latency number isn’t the most accurate in absolute terms, but all we are looking for is stability.

How to Record DVR

Set your recording preference in the FPV Goggles menu: Settings => Record Set.

You can choose either to record in the VTX or in the Goggles. But VTX only has 8GB onboard memory and it gets filled up very quickly (about 20mins of 1080p footage).

You can change resolution if you are recording in the air unit, between 720p 60fps and 1080p 30fps. However you cannot change resolution for the FPV goggles recording (DVR), as it’s fixed at 720p 60fps.

By default, the DVR starts when you arm the drone, and it automatically stops and saves the video when you disarm. You can also start recording by pressing the Record button by changing the setting in the goggles.

OSD data is saved in a “.srt” file (subtitle format), these are just plain texts, you can overlay it on top of your video when you play it, or edit it, similar to DJI FPV system.

Uploading FPV Footage to Youtube

I’ve found the best way to upload Walksnail Avatar footage to Youtube is to “upscale” them to 2K, or even better 4K, keep the bitrate at original 55Mbps. This is because Youtube retains higher playback bitrate for videos with higher resolution.

Flashing Firmware

You can download firmware files from one of these sites:

Official releases: https://caddxfpv.com/pages/download
Latest/Beta releases: https://avatar-firmware.d3vl.com/
Fatshark’s own download site: https://fatshark.helpscoutdocs.com/article/174-dominator-with-avatarhd

Make sure to power your goggles and VTX with a fully charged battery as the update can take up to 10 minutes. Powering down during update might brick your devices.

Fatshark Dominator HD goggles can flash the Avatar Goggles firmware (that’s what I’ve been doing and no issue so far), and according to many comments I’ve read online they are basically the same goggles just different in colors.

The Avatar Mini Gnd is for Fatshark Recon HD Goggles.

How to Update Firmware on Goggles

Download Avatar_Gnd_xx.xx.x.IMG
Take the SD card out of the goggles and insert it into your computer
Put the Avatar_Gnd_xx.xx.x.img file to the root directory of the SD card
Eject the SD card and put it it back into the Avatar goggles
Power up the goggles and wait until you see the Standby screen
Push and hold the Link button for 8-10 seconds. The headset screen will go black indicating the start of the update process
The update will take a few minutes
During the update, the goggles will beep. This is normal. DO NOT turn off the headset until the update is finished
When the update is complete, the beeping will stop and the headset will boot back up to the Standby screen

Important: Every time you update firmware you should also reset all settings (In the menu, settings, select Reset All) otherwise something might not work properly. This is a known bug in the Avatar system currently as in Aug 2022.

How to Update Firmware on VTX

Download Avatar_Sky_xx.xx.x.IMG (for the 1S mini VTX, download the MiniSky file)
Connect the Air Unit to your computer using the USB cable that comes with the Air Unit
Power up the Air Unit – if the Air Unit is installed in your drone, simply power up your drone from a LiPo battery, make sure to take propellers off for safety
An external drive should appear on your computer, put the Avatar_Sky_xx.xx.x.img file to the root directory of the Air Unit
Eject storage, and disconnect USB cable
The LED on the Air Unit should be blinking green slowly
Push and hold the Link button on the Air Unit for 8-10 seconds
The LED will turn off indicating the start of the update process, during the update the LED will blink red
When the update is complete, the LED will blink green

You will have to bind your VTX to your goggles again, and you also have to perform the FCC mod again.

How to Downgrade Firmware

If you are trying to roll back to one of the older firmware, you need to rename the firmware files to a version that is newer than the current one on your device. The flashing procedure is the same.

Once you’ve downgraded, you should delete these renamed firmware files on the device to avoid confusion in the future.

Goggles Beeping Status Indicator

Pairing: beep….. beep….. beep….. (about one second apart)
Updating firmware: beep………. beep………. beep……….. beeeeeeeeeeeeeeep (long interval beeps, when update is finished, it constantly beeps for a few seconds to indicate that)
Update failed: beep.. beep.. beep.. (rapid beeping)

Air Unit LED Status Indicator

Connected to goggles, working as normal: green solid
Waiting for connection to goggles: green rapidly flashing
Connected to goggles, but has issue with image: green slowly flashing
Pairing: red solid
Updating firmware: red rapidly flashing

Updating OSD Font

Download new OSD font files here: https://drive.google.com/file/d/1c3CRgXYQaM3Tt4ukLSIvoogScQZs9w49/view (link provided by Caddx)

To change font parameters, modify font_update.ini
Copy font_update.ini and font png files to the SD card in the goggles, put SD card back in the goggles
Open goggles menu [display], click [Font Update] to update font, select [Custom Font] and exit menu
Done

Video Out from Goggles USB-C

You can output video from the Avatar FPV Goggles to an external display via the USB-C port.

The Betaflight OSD will be displayed and you can’t remove it. For some people it solves the problem as the goggles DVR doesn’t record Betaflight OSD. But for those who want a clean feed without Betaflight OSD, it’s currently not possible.

Monitors

Hardware requirement:

A monitor with HDMI input
USB Type C 3.1 to HDMI male adapter cable (about $10-15):

In your FPV Goggles, switch to Standard frame rate, power off goggles
Turn on your monitor, take your USB-C to HDMI cable, connect the HDMI side to the monitor and connect the USB-C side to the goggles before turning on the goggles
It shows a weird blocky transition at first and takes a few seconds to stabilize but video should be good after that

After the first successful connection to the monitor, the goggles should keep HDMI/Displayport enabled as long as it’s powered on, and you can disconnect and reconnect the monitor as often as you want, as long as you don’t turn off the goggles in between.

Troubleshooting if video out is not working:

If you are having issue, double check if the goggles are in High frame rate which sends out a 100Hz video. Most Monitors DO NOT support 100Hz. Make sure to set the goggles to Standard frame rate (60Hz)
You have to connect the TV/monitor first into the goggles (and power the monitor) BEFORE you power up the goggles, otherwise HDMI/Displayport out is DISABLED in the goggles

Android Phones

Unfortunately, it DOES NOT support iOS yet (sorry iPhone users), only Android is supported at this point.

The steps to connect to a phone is the same as using an external monitor. In addition to the USB-C to HDMI cable, you will also need a HDMI to USB-C video capture card. Also you need an Android App installed to show the video feed.

The advantage of an Android device is you can use High frame rate (120Hz) just fine, unlike most monitors that are limited to the Standard frame rate option (60Hz).

Steps:

On the phone, enable developer mode (system -> settings -> developer), if unsure google how to do it
Plug the USB-C to HDMI cable into the goggles
Connect the capture card to USB-C to HDMI Cable
Plug the capture card (USB-C) into your phone
On your phone you should be prompted to select an app for the USB Device, select OTG View2 (you can download in Play Store)
Power on the goggles (It’s important that you do this LAST! Otherwise HDMI/Displayport out is DISABLED in the goggles)

After the first successful connection to the phone, the goggles should keep HDMI/Displayport enabled as long as it’s powered on, and you can disconnect and reconnect the phone as often as you want, as long as you don’t turn off the goggles in between.

Windows and Mac

Similar to how it works with Android devices.

Hardware/Software requirement:

USB Type C 3.1 to HDMI male adapter cable (about $10-15):

HDMI to USB-C video capture card (about $10-15)