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        Discussion Another very cheap head tracker device

#1 randall1959 Jul 27, 2008 10:55 AM

Another very cheap head tracker device
 
I would like to pan my camera on my Easy Star via some head tracking setup of some sort but really don't want to go to the expense of buying a head tracker compatible radio.
My camera only pans so I'm sitting here wondering how to hook up a gyro which would only have to be one axis, to the rudder channel in my rc tx?
Or, maybe some mechanical means via a twist cable that would be mounted to the side of my head and terminating at the rudder gymbal.
I would think that somehow it could all be done electronically though. I'm using a Hitec Focus 4 so would it be possible to take command of channel 4 via the buddy box connection?

#2 CATPart Jul 27, 2008 11:11 AM

there was another guy here that hooked up a potentiometer to a rod on his head, so when he turned his head the input on the POT would twist and that was wired in through his trainer port (maybe wired directly into the Tx, i forget). there is a thread all about it here somewhere.

#3 PeteSchug Jul 27, 2008 11:11 AM

It sounds a lot like you are trying to design a head tracker rather than buy one.

Pete

#4 randall1959 Jul 27, 2008 11:19 AM

Quote:

Originally Posted by PeteSchug
It sounds a lot like you are trying to design a head tracker rather than buy one.

Pete

Yes, that's my idea. I'm thinking I'll experiment with a couple of old tx's I have lying around and take the rudder pot out of one. Maybe I can design some sort of cable operated aparatus to rotate the pot. I wish there was some simple way to hook up a single axis gyro directly to a servo.
Then the servo could be attached directly to the pot.
I've been moving into smaller quarters lately so along with that, expenses have gone up somewhat and I'd like to find some simple way (ie cheap :rolleyes: ) to use what I have around here.
My camera only pans and I don't really care about tilt so there has to be some simple way to accomplish this.

#5 Jensst Jul 27, 2008 12:37 PM

You mean something like this:

DIY Head Tracker for FPV (1 min 7 sec)

or
L-B-H-T--LOW-BUDGET-HEAD-TRACKER---NEW VERSION-!! (5 min 0 sec)

#6 scrtsqrl Jul 27, 2008 01:29 PM

Scrtsqrl's Poor Man's Head Tracker (3 min 40 sec)

Bore Strand (5 min 25 sec)

#7 randall1959 Jul 27, 2008 02:08 PM

OH WOW Scrt's idea is amazing but I've also hit on another idea while out driving around this morning.
I'm going to extend the wires on the rudder pot like you did, except that I'm going to mount a gyro on the headgear I use to wear my video receiver. Then I'm going to run that and the servo into a micro receiver on the same channel as my plane. That would allow me to mount the servo so that it actuates the pot. I could wear the whole setup on my headset and only have one small lead down to the rc tx.
I could mount the gyro, servo, pot and rx into a small box that I could simply attach to the helmet.
I'll post pics once I start the mods.

#8 CATPart Jul 27, 2008 02:17 PM

so the gyro will sense your head movement, adjusting the servo position (headfing hold gyro I assume?), the servo will turn the POT and the POT will be running a channel on your transmitter, is that what you are thinking?

#9 nathanj988 Jul 27, 2008 03:30 PM

I don't think a heading hold gyro will work. A heading hold gyro moves the servo enough to bring it back into proper heading, as the name implies. The problem that I see is that the gyros movements aren't affecting what it is sensing, or your head. That didn't sound right, what I mean is that when the gyro tries to recenter your head, it won't be successful, so it will use more movement, but not linear movement compared to the input. I have an extra GY401 hear that I'll play with to see what happens.

#10 nathanj988 Jul 27, 2008 03:43 PM

I played around the the 401 and that gyro wouldn't work for headtracking. Like I tried to say before, the movements aren't linear and the servo can go to full throw quickly. Mine was also quite jumpy.

#11 CATPart Jul 27, 2008 03:51 PM

Good point nathan, that makes sense what you said about the HH gyro. He would then need to mount the gyro on the same servo that the gyro is controlling Then the servo would seek the HH position of the Gyro. The same servo would turn the pot that controls the pan channel on his transmitter. Sounds like it might work right? So basically as he turns his head, the gyro wil turn in the opposite direction and maintain its HH position. hmmm....i wonder if this would have feedback issues like resonance. The gain would probably have to be tuned just right.

#12 randall1959 Jul 27, 2008 04:37 PM

I'll be using a focus 4 so I can set the epa mechanically also.

#13 KeithLuneau Jul 27, 2008 05:38 PM

What are the chances that the pot inside the servo has the same resistance as the one on the rudder stick? If you're lucky enough for that to be the case, that would eliminate the need for a servo arm and linkage running another pot. Just replace the pot in the radio with a cable running to the one in the servo, and drive that servo with the gyro, no servo arm... :D

That's pure speculation though, as to whether or not it'll work even if the pots are the same! Call it a theory, if you will.

#14 randall1959 Jul 27, 2008 07:05 PM

I think that attaching a servo directly to the pot, although not as clean looking, will be the less troublesome method. I might even have to spend a few dollars and get a better gyro, but if what I'm trying to do works, it will be worth it, at least for me.
I'm going to put the receiver for the pan unit on my helmet along with the gyro. Then I'll simply run a servo lead down to the tx and either mount the servo internally if I can or move the pot somewhere on the tx to mount the servo to.
I'm just about done moving so by wed I can start the tinkering process..... :D
I've heard about drift with using a gyro, but doesn't the control surface go back to neutral without any input? That would mean if it started drifting all I'd have to do is hold my head straight a second or two.

#15 randall1959 Jul 27, 2008 09:37 PM

I was going to go back to 3 channel and drop my ailerons but I forgot something. I have this plane on a Hitec Prizm 7 at the moment, and the pan servo is on the flap dial. I'll just mount the receiver and gyro on my FPV helmet, then run a servo lead down to my transmitter and run the servo directly onto that knob somehow. I just hope I don't have the same problem I did on another plane not being able to find center. This is on a different channel so maybe I'll get lucky.


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