Re: TrackClip project
Posted: Thu Jul 02, 2015 8:42 pm
In case this helps anyone ...
I went ahead and built a 3 IR LED "Hat Clip Pro" and it seems to work very well. The only dimension I found advantageous to change relative to the original hat clip was to increase the "height" of the center LED about 1/2 inch (helps with the range for looking up, like at an aircraft overhead panel, but reduces the "look down" range a bit). This configuration tracks well in all directions to just about the limits of my ability to see my 28" screen out of the corner of my eye. As discussed above there does not seem to be a way to shut off the IR transmitters in the camera when the software is in the Hat Clip mode (which it must be), so I lowered their brightness as much as possible (setting of 10). I also increased the filter setting to the max of 253 since the TrackIR Hat Clip software is looking for a faint IR reflection rather then a relatively strong transmitted IR signal.
I used OSRAM SFH4556P wide angle (130 deg) IR LEDs -- they are available from Mouser Electronics for less than 50 cents each.
I found it is best to keep the size of the "green dots" as seen on the Track IR display as small as possible, while still having reliable performance, because if two of the dots merge, as will tend to happen in certain head positions, the tracking freezes. So smaller dots are better than large blobs that will merge "sooner" for a given head position. To this end I found it best to run the LEDs at low power, which is not a problem since the software is looking for a faint reflection. My "Hat Clip Pro" is powered by 5 volts thru a USB connection (I used the USB cable from an old mouse -- 50 cents at the local flea market) and wired the LEDS in series along with a 10 ohm resistor. This results in about 50mA of current (the LEDs are rated for a nominal current of 100mA) which helps to keep the dot size small and the power demand low. The frame/bracket for holding the LEDS looks similar to the Hat Clip in general shape (basic T shape) and was made by bending and super gluing together two pieces of thin metal strap I had in my junk box. I spray painted the bracket flat black to reduce potential reflections. The LEDs were mounted on 1/4" plastic "blocks" glued to the metal frame (the LED leads pass thru two tiny holes in the blocks). It also helps to design the bracket/LED mounting so that the two front LEDs protrude a bit past the end of the cap peak so they are not "blocked out" from the camera by the hat peak when looking up. I use a spring clip to fasten the "Hat Clip Pro" to the peak of my hat.
I personally find the "Hat Clip Pro" a viable alternative to the TrackClip Pro. I prefer not to have anything hanging off the side of the headset I use for flight simulation, and I happen to find wearing a baseball type cap comfortable. Since I had stuff like wire, the metal straps, and paint lying around, my cost for the "Hat Clip Pro" was less than $10 or so, and about half of that was the IR LED shipping cost from Mouser. I judge the performance of the "Hat Clip Pro" to be a definite improvement over the original Hat Clip (mainly wrt tracking range), but not dramatically so. All in all an interesting and fun project.
Al
I went ahead and built a 3 IR LED "Hat Clip Pro" and it seems to work very well. The only dimension I found advantageous to change relative to the original hat clip was to increase the "height" of the center LED about 1/2 inch (helps with the range for looking up, like at an aircraft overhead panel, but reduces the "look down" range a bit). This configuration tracks well in all directions to just about the limits of my ability to see my 28" screen out of the corner of my eye. As discussed above there does not seem to be a way to shut off the IR transmitters in the camera when the software is in the Hat Clip mode (which it must be), so I lowered their brightness as much as possible (setting of 10). I also increased the filter setting to the max of 253 since the TrackIR Hat Clip software is looking for a faint IR reflection rather then a relatively strong transmitted IR signal.
I used OSRAM SFH4556P wide angle (130 deg) IR LEDs -- they are available from Mouser Electronics for less than 50 cents each.
I found it is best to keep the size of the "green dots" as seen on the Track IR display as small as possible, while still having reliable performance, because if two of the dots merge, as will tend to happen in certain head positions, the tracking freezes. So smaller dots are better than large blobs that will merge "sooner" for a given head position. To this end I found it best to run the LEDs at low power, which is not a problem since the software is looking for a faint reflection. My "Hat Clip Pro" is powered by 5 volts thru a USB connection (I used the USB cable from an old mouse -- 50 cents at the local flea market) and wired the LEDS in series along with a 10 ohm resistor. This results in about 50mA of current (the LEDs are rated for a nominal current of 100mA) which helps to keep the dot size small and the power demand low. The frame/bracket for holding the LEDS looks similar to the Hat Clip in general shape (basic T shape) and was made by bending and super gluing together two pieces of thin metal strap I had in my junk box. I spray painted the bracket flat black to reduce potential reflections. The LEDs were mounted on 1/4" plastic "blocks" glued to the metal frame (the LED leads pass thru two tiny holes in the blocks). It also helps to design the bracket/LED mounting so that the two front LEDs protrude a bit past the end of the cap peak so they are not "blocked out" from the camera by the hat peak when looking up. I use a spring clip to fasten the "Hat Clip Pro" to the peak of my hat.
I personally find the "Hat Clip Pro" a viable alternative to the TrackClip Pro. I prefer not to have anything hanging off the side of the headset I use for flight simulation, and I happen to find wearing a baseball type cap comfortable. Since I had stuff like wire, the metal straps, and paint lying around, my cost for the "Hat Clip Pro" was less than $10 or so, and about half of that was the IR LED shipping cost from Mouser. I judge the performance of the "Hat Clip Pro" to be a definite improvement over the original Hat Clip (mainly wrt tracking range), but not dramatically so. All in all an interesting and fun project.
Al