Flytron DT-3K Headtracker Review

This is the Flytron DT-3K Headtracker.

The headtracker came nicely packed in an anti-ESD bag. It’s very compact and light weight, which keeps down the shipping cost. The DT-3K headtracker doesn’t come with a physical manual, but inside the package is a note with the address to an online manual. The manual is very clear and easy to understand, containing illustrative pictures and detailed instructions.

On the top of the headtracker you will find a single button and a tiny hole underneath which is for an LED. The entire construction feels very robust. The plastic case is very sturdy and is equipped with two mounting tabs, which will make it easy to mount. The cable is thick, yet nice and flexible. It feels like it can used for a 100 years without breaking. The DT-3K headtracker can be bought with a wide range of different connectors, since I’m a Futaba guy I got one with a Futaba-square connector.

A headtracker, for those of you that doesn’t know, is a device mounted to your head. It converts the pan and tilt movement of your head into a digital signal which is fed into your radio, transmitted to your airplane and moves your FPV camera around. If used in conjunction with video goggles it makes you feel like you are sitting in the plane moving your head around. It’s a powerful experience making you feel much more immersed in the flight.

Features:
Size: 65x35x16mm (including mounting tabs)
Weight: 70 grams (including wire and connector)
Available connectors: Futaba square | Futaba round | Hitec round | Airtronics/sanwa plug | e-sky mini round | JR jack with external battery connector
Operating voltage: 6-24V
Current consumption: ~10mA

The DT-3K headtracker has two features that sets it apart from other headtrackers. The first one being its PPM-Inject feature which makes the headtracker create two extra channels and insert them back into the radio. This means that you can use this headtracker even with a simple non-programable 4 channel transmitter. The headtracker makes the 4 channel transmitter transmit 6 channels! (The use of this feature obviously requirers a 6 channel receiver, though.)
The second feature is that it uses a magneto-gravity hybrid sensor which promises zero drift, but at the cost that you need to face either north or south.

The DT-3K doesn’t require an external battery, as it is directly powered via the trainerport, which is nice. Since the current draw is very low (around 10 mA) the battery life of your transmitter is hardly effected at all.

Since the DT-3K headtracker needs to be mounted on you head I recommend mounting it on a cheap baseball cap, or on you video goggles with double-sided tape . The case has two mounting tabs on the sides which are big enough for M3 screws. Mounting it on a cap is as easy as drilling two holes in the cap and securing it using two screws and nuts.

The cable is just a bit over 1 meter long which is a good length. Not too short nor to long. Unlike gyro based headtrackers which goes crazy if you move them during boot up, the DT-3K headtracker can be moved around during boot up. I find this very positive as you can have the headtracker on your head, unplugged, not having to have the transmitter in your lap while you’re setting everything up, starting the recording, fiddling with cables and so on. And when it is time to fly you simply plug it in and power it up.

Configuring:
The DT-3K headtracker is programmed using the one button and LED on the top of the unit. Programming is a fairly easy task. To get into programming mode you simply hold down the button before you power it up, and continue holding it down for a couple of seconds and then release it, the LED will start to flash repeatedly. You have now entered the programming mode. There are four different programming steps that you have to complete before the settings are saved.

To enter the first one you simply hold down the button and the LED will start to flash. Keep holding down the button! The LED will start to flash in a pattern. This first step is the channel selection. Count the number of flashes. 1 blink means that it will operate on channel 1 and 2. 2 flashes means cannel 2 and 3 and so on. When you get to the number you want you simply release the button. The LED will flash rapidly confirming your choice.

Push and hold the button again to enter the second stage. In this stage you select if you want the headtracker to operate in PPM-Create mode (simple transmitters) 1 blink or PPM-Insert mode (advanced transmitters) 2 blinks. Release the button to select.

Push and hold the button again to enter the third stage. This is where you select which way the pan servo should move. 1 blink = normal, 2 blinks = reversed. Release the button to select.

Push and hold the button for the fourth time. This time you will select the way the tilt servo moves. 1 blink = normal, 2 blinks = reversed. Release the button to select.

The headtracker will now flash rapidly and then reboot automatically. It sounds complicated when you read it but it’s quite intuitive. It takes no more than 30 seconds to program this device.

Calibrating the center and gain:
Before you use the headtracker for the first time you need to calibrate it. This is a very simple process. Put the headtracker, which you’ve mounted on a cap or goggles, on your head and power it up.

Look north or south depending on which way you plan on facing when you are flying. While looking straight ahead, push and release the button on the top of the headtracker.

Turn your head to the left, then to the right, then up and last down. The DT-3Kheadtracker will sense how far you moved your head in each direction and save that value as the max point. (Maximum is 30° in each direction)

Push the button again to save and exit.

You’re done! You only need to do this once since neither the magnetic field nor gravity of the earth changes very often (if it does we have far greater problems to worry about). If, however, you were facing north when calibrating and you want to face south instead (or vice versa) you will have to re-calibrate.

PPM-Inject/PPM-Create:
The DT-3K headtracker has a very cool feature called PPM-Inject. Like I’ve already mentioned it can make a simple 4 channel transmitter transmit 6 channels with the two last being the headtracker signals. But it can also use a 6 channel transmitter and “over-write” the two last channels or make your 6 channel transmitter transmit 8 channels. This is extremely useful since most flyers doesn’t have a “pro” transmitter in which you can select which channels the buddy box is allowed to take over.

The PPM-Create feature simply sends blank (centered) signals on all channels not used and you have to program the transmitter only to accept input from the channels you set the headtracker to operate on.

Flight report:
With the DT-3K headtracker mounted on a cap I took it out for the first test flight. It was a chilly autumn morning and the mist had yet to clear away. I placed my foldable chair facing north, powered everything up, tested every thing, just to make sure that it all worked and took of. Here is the video;

(The movement is a little jerky due to HXT900 servos imprecision)

I’ve flown with other headtrackers before but the DT-3K is in a totally different league. It’s so precise and smooth. The resolution is great and it has no trouble following even the fastest head movements. I tried to fool it by shaking it in all directions, turning it upside down and swinging it around, then placing it in the original position checking if I had succeeded – I hadn’t. It was perfectly centered in both planes. But the best thing is that it really has zero drift. I’ve even flown with it in -12°C with the unit placed on the top of the video goggles, a place which gets warmer during the whole flight, and even then it didn’t drift. Every other headtracker I’ve tried that promised zero drift has drifted severely during this test, but not the DT-3K!

The only negative thing I have to say about the DT-3K is that you have to face north or south during flight. However I found this less of a hassle than I thought it would be. I simply place my foldable chair facing north, setting the trainer switch to the off position (disabling the headtracker), stand up facing the wind, launching the airplane into the wind, sitting down again and flicking the trainer switch to its on-position (enabling the headtracker again).

Conclusion:
This is the best headtracker I’ve ever tried. Flawless precision, great resolution and very smooth head-tracking without the slightest jerking, stopping or jumps. It’s easy to mount, lightweight and built to last for a hundred years. The PPM-Inject function makes this headtracker work with simple transmitters, as well as advanced ones, so there is no need to buy an expensive transmitter just to be able to use head-tracking any more.

Pros and Cons:
+ Truly Zero drift
+ Works with both advanced and simple transmitters
+ Easy to configure and use
+ Cheap
+ Small
+ Lightweight
+ Robust construction
+ Sturdy cable
+ Easy to mount
+ Available with a wide variety of connectors
+ Good instructions

– Must face north or south