The Hat Cam
July 7th, 2008 captain
I have been looking for a simple helmet/hat mounted camera system, so I could shoot video of the review aircraft in flight. I looked at bullet cameras that are normally used for this purpose, but was put off by the need for separate microphones, battery packs and recorders. There are a number of all-in-one systems available but they are either expensive or have poor video quality.
I wanted something that would be self-contained, robust and waterproof. The Twenty20 VholdR looked promising, but the UK price was too high. I then looked at digital compact cameras. There are two brands that are advertised as robust and waterproof by Olympus and Pentax. The Olympus models would only record 10 seconds of video at 640×480 so that left the Pentax W30 that would record at maximum quality until the memory card was full – about 40 minutes. I also liked the fact that the lens and tripod mount were located centrally.
The next task was to mount it on a hat. Unless I take it snowboarding, I don’t have a need for a helmet, but finding a suitably rigit hat was difficult. In the end I found the Vitrex safety cap and the Scott International Bump Cap. Both are baseball caps with a padded hard plastic insert, producing lightweight head protection without the need for a full helmet. My local tool supplier had the Scott.
The plastic insert provides excellent support for a camera mount.
The mount was formed from a large plastic washer I found at work. It’s 72mm diameter and 3mm thick with a 19mm diameter hole. I heated it up using a 300W hot air gun and bent it to a suitable angle. Once cooled, I drilled two 3mm holes for connecting to the hat insert. The mount was then held in place against the hat and one of the holes drilled through. This hole was used to fix the mount to the hat using a 3mm nut and bolt, before the second hole was drilled through.
After removing the mount, the hat insert holes were countersunk so that the bolt heads would be flush and not stick into my head.
The tripod mount screw was obtained by purchasing a quick release tripod platform and removing the screw. You could also use a 1/4″-20 bolt if you can find a source. So that the bolt would not fall out when the camera was not attached, I drilled a slightly oval 5mm hole. The screw was them placed against the hole and then turned while pressing hard. This caused the screw to cut a thread in the plastic. With the screw right through it’s wasted portion is in the hole and so will rotate freely but cannot drop out.
The rubber washer was bonded to the mount after finding that the screw was bottoming out in the camera before attaining full tightness.
The whole system was mounted on the hat using M3 countersunk bolts with washers and nuts. The bolts were initially too long, so I cut them back using a Dremel type multitool.
The first few attempts recording some flying footage highlighted some room for improvement. The main issue was getting the hat on straight and level, so that the object was in the middle of the frame when looking straight at it. On one flight the helicopter kept disappearing off the frames left edge.
To fix this I borrowed a trick from the VholdR. I purchased a small keyring presentation laser to act as a reference. A mount was made by folding a plastic strip around the laser after softening it with the heat gun. The holes were made using a hole punch. An extra hole was drilled on the mount for a 4mm countersunk bolt to hold it firmly in place.
Now I could mount the camera on the hat and the hat on my head such that my point of interest was centre frame. The procedure runs as follows.
- Turn the camera on.
- Point the camera at an object so that it appears in the centre of the LCD.
- Press the button on the laser and see where the dot appears.
- Twist the camera on the mount towards the dot.
- Repeat steps 2 and 3 until the dot hits the centre of the object.
- Switch the camera into movie mode if needed.
- Place the hat on your head.
- Look at the object.
- Press the button on the laser and see where the dot appears.
- Rotate the hat so that the dot points towards the object.
- Press the shutter button and start filming. Remember that the camera lens is 5 or 6 inches above your eye level when filming close up.
After some use, I found that the laser support had cracked at the sharp fold. I would have preferred to replace it with aluminium, but was unable to source some locally. Instead, I used some plastic strip that was thicker than the original.
Sample Video
The sample video below of the Palm-Z has been reduced in size and compressed from the original 42Mb MJPEG 640×480 quicktime file.
Final thoughts
I have been pleased with the results from the finished HatCam. The only issue is the weight of the camera. If the size adjustement is loose, then quick head movements can cause the brim to droop over your eyes. This is rare however and easily prevented by keeping the adjuster tight.
An alternative would be to add a counterweight at the back of the hat, although the best solution would be a lighter camera. One recent possibility is the new Flip Mino Camera which has a tripod mount and weighs a mere 95 grammes compared to 160 grammes fot the Pentax Optio W30. It uses H264 video compression so the picture quality is not quite as good as the Pentax’s MJPEG but uses considerably less disk space.
