X-Wing Pilot Chest Box FPV

troop-pic

November, 2016

The Chest Box is a required feature for a complete X-Wing Pilot uniform.  There are many talented people who sell them, and they are relatively inexpensive.  I got mine from Darth Hair and love it!  He uses vacuformed ABS plastic for a hollow body, then adds resin rocker switches, acrylic tiles and machined aluminum disk, knob and jack.  It’s very screen accurate and good enough to get into the Rebel Legion without any modification.

Chest Box.jpg

Unmodified chest box

 

After my acceptance into the Rebel Legion, I wore my costume and accompanied R2-D2 to the delight of the young and young-at-heart Star Wars fans.  With my hands occupied with R2’s remote control box, I found that I had no way of capturing some of the priceless moments of interacting with fans during the troop.  I starting thinking it would be great to be able to have a mounted, hands-free way to capture images while I was trooping, since I had no dedicated handler to help record the events.

From my experience working with RC quadcopters, I know that First Person View (FPV) camera systems are small, lightweight, and easy to configure.  I got the idea that I could mount an FPV camera inside the chest box and have it record the video.  A friend of mine told me about this very clever new wrist-mounted FPV screen which I thought would be perfect to complement the chest box.

 

Parts

To complete the project, I used the following parts:

  • FPV Camera with 5.8GHz transmitter – Easier to buy the camera and transmitter as a bundled set since they come with all the right JST connectors for the wiring.  This is a 148 degree camera that gives a bit of a “fisheye” view during playback.  It has 800 TVL which is high quality, and also a 600 mW transmitter which allows for a much longer range than I’ll ever need considering the receiver is strapped to my wrist.
  • Eachine ProDVR – Wired in-line between the camera and transmitter so that it records a clean image without any transmission artifacts.  I really like this unit for many reasons.  One of them is because it exposes pins that allow you to wire external buttons for control of the DVR functions.  This requires a Mini-SD card for operation.
  • 32GB Mini-SD Card – for the ProDVR.  Depending on the recording settings, this will provide capacity for up to 8 hours of recording time.
  • A pair of 11.1V rechargeable batteries – Only 1 needed at a time, but always good to have a backup.
  • A LiPo Guard bag – Safety first!
  • FPV Watch with 5.8GHz receiver – It has a 2.6″ screen.  I only wish it came in orange.
  • Small piezoelectric microphone
  • 3 momentary NO push button switches – for controlling the ProDVR.
  • A slider on/off switch
  • An LED indicator light

The add-on parts (excluding the chest box) cost about $150 USD.  Note that I did have some parts (buttons, switches, LED) and all the required tools already.

 

Assembly

I started by removing the straps from the chest box.  Next I unscrewed aluminum jack from the chest box and widened the hole so the camera lens would fit through.  I also drilled a pinhole right through the middle of the white circle on the top so I could add a microphone.  I drilled out 3 holes on the left for the momentary push buttons needed to control the DVR.  I drilled 1 hole on the right for the transmitter antenna and cut a hole for the on/off slide switch.  I also widened the big hole in the back of the chest box so I could work inside more easily.

I connected 4 nylon stand-offs and screwed them to the front side of the FPV camera.  I then placed the camera inside the chest box and glued the stand-offs to the inside of the box to keep it stable.  I glued the piezoelectric microphone inside the chest box behind the pinhole I drilled.  I also gently removed some of the ABS plastic, then glued into place a LED behind one of the acrylic squares to act as a power indicator.

I used the JST wires that came with the camera and DVR to connect everything together. The trick was to connect the DVR monitor output to the transmitter so I could see on my FPV watch when the unit was recording and other vital stats.

In order to keep the new additional components as discrete as possible, I added some paint.  I painted the buttons and switch grey to match the chest box.  I also painted the lens cap of the camera silver to match the aluminum jack I replaced.  Unfortunately, no good way to hide the large antenna off to the side, but it seemed to fit in well, and I didn’t fuss with it.

Selecting a battery was an interesting challenge that took some research.  I wanted one that was small and lightweight, yet had enough power to last a full troop on one charge.  I settled for the Tenergy 1600mAh Lipo pack and it seems to meet my needs.  I’ve used it for up to 5 hours without issue.

Chest Box - Modified2.JPG

Chest Box - Modified3.JPG

 

 

Conclusions

Overall, the FPV cammera addition is a great success.  I really enjoy being able to play back an entire troop afterward and doing screen grabs of anything interesting that happened.  Given the opportunity, I also like to show it off to folks who are interested – the FPV watch is a nice way to explain what its doing and how it works.

The additional components (except for the battery) are light enough that they add an unnoticeable amount of weight to the chest box.  The battery does add a bit of extra weight, but not too bad.  I don’t really feel any warmth or discomfort radiating from the box through my costume, either.

I try not to think about the spaghetti mess of wires inside the chest box, *sigh* – I’m not proud of that, but it is a necessary evil.  There is plenty of room to tuck everything inside and have it all unseen.

 

Lessons Learned

  • The FPV watch has a small battery and therefore a small run time.  I turned it on and left it on for one troop and it was dead within 2 hours.  Now I just leave it off and turn it on only when I want to check something.
  • The 5.8GHz transmitter gets very hot when running, so keeping the antenna screwed in helps to keep it away from the ABS plastic and prevents melting or suffocating the electronics.
  • The ProDVR has a built in feature to allow continuous recording for many hours.  When a recorded file size gets too big (600MB), it automatically closes the file and makes a new one.  This is a really nice feature!
  • I once recorded an entire troop, only to find that the camera was out of focus!  The camera is focused by adjusting the screw threads on the lens.  Focus is not easy to see on a small screen, so now I’ve focused it and glued it together to prevent accidental movement.It does have a set screw for this purpose, but now that the camera is installed, I can’t reach it anymore.
  • After assembly, I realized that I really only ever use one of the 3 ProDVR buttons to turn on/off the recording.  The other 2 buttons are for other menu functions which I could do 1 time during setup.
  • The power indicator LED was a nice addition to help debug issues in the field.  Knowing that the circuit is getting power is a good first step in solving any issues.  In addition, it makes the chest box look pretty cool.
  • The lens cap is important for protecting the FPV camera lens during transport.  However, it’s also a nice way to hide the modification during a careful costume inspection.
  • LiPo’s are dangerous and must be handled with respect at all times.  A Lipo guard bag is a good idea for storing and charging any Lipo battery.  I highly recommend them!
  • Banggood has very good prices on consumer electronics, but terrible customer service.  ‘Nuff said.

 

Next Steps

  • The DVR microphone input does not have a pre-amp so the audio quality is quite poor.  I can hear my voice, but usually can’t hear others nearby in the recording.  I bought an Adafruit Electret Mic Amp MAX9814 and plan to wire it inline to the mic to see if I can get better audio quality.  It has a really cool feature of allowing dyamic amplification to avoid cut-out of the audio. I’ll de-solder the mic that comes on board and wire in my own.
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