The helmet-cam is useful anytime you want video but you don't want to use a hand or second video-person on the project. We use ours to record the designing and building of HowToons projects. It can be an invaluable anlysis and learning tool for rapid prototyping.
photo: Erich Brandeau sports a sweet helmet cam.
Step 1: Parts Layout
Materials List for Waterproof, hands-free video recorder. I've listed the specific parts I used to build a working helmet cam, as well as the basic functional requirements for each part so that alternatives can be explored.
+ Camcorder: Sony HCR-DC32, $300 @ bhphotovideo.com
This model, now discontinued by Sony, has a/v input and LANC remote control capabilities in a miniDV format. When bought new, it also comes with an a/v cable and parts necassary for uploading video to computer for editing. Look for any camcorder with a/v input and LANC in a modestly sized package.
+ Camcorder Case: Pelican 1120 Case, $20.95 @ bhphotovideo.com. These cases come in different sizes, the 1120 works well with the camcorder we spec'd. I would not recommend cheaping out on this step - you want your box to be able to go swimming, in case you fall off of you kite-powered catamaran or something.
+ Waterproof Connectors:
As described later, you will need 3 sets of plugs to connect the outside world to the world inside the pelican case, 1 for the remote, 1 for the microphone, and 1 for the external camera lense.
I use Conxall waterproof connectors (pg. 264 of the current digikey book).
In digikey-part#-speak: order sc1275-ND & sc1264-ND (for lanc), sc1277-ND & sc1266-ND (for video signal), and sc1281-ND & sc1270-ND (for microphone). There are a number of connector combinations that will work. By using three different connector pairs, the connections are mechanically programmed not to get mixed up. Total cost of connectors should hover around 30$.
+ External Camera Lense: 580 Line Sony ExView HAD Helmet Camera (3.6mm), $205.99 from hoyttech.com, and $34.99 for the camera protector (get the protector). A number of bullet cameras are availiable, but this lense is fairly high-res. The 3.6mm lense makes for a decent field of vision, though if I could find a wider angle lense, I would probably use it.
+ Remote Control: LANC remote control, $64.99 from hoyttech.com. LANC comes in a few versions for different cameras. See the website to pick the version for your camera.
+ Microphone: stereo high gain microphone, $28.99 from hoyttech.com
(hoyttech sells the above mentioned parts in packages, too.)
+ Camera Mount: there are a lot of options here. Hoyttech, among others, distributes mounts for a helmet and a headband for no helmet. $10-30
+ Backpack: any backpack should work, though a sports or outdoors oriented pack will fit tighter, minimizing fatigue and distraction. I use a camelbak M.U.L.E., $80 at REI.
+ 12 V Battery (to power mic and video): Easiest to use 8 AA batteries in series; you will definently want rechargables for this operation. I chose to separate the video and audio signals, so I used 2 battery packs. A set of batteries and charges ~$40.
+ Battery Holder: An 8 AA battery pack is overpriced at hoyttech. These are available at radioshack or digikey for well under $10 each. You can also make your own.
+ miniDV Tapes: if you start documenting everything you build the tape-time will fly. I get tapes at 33$ a half-dozen at bestbuy, but that's largely a location convenience ... shop around.
+ Hardrive Space: if you start editing video heavily, you will probably need disc space. Using typical video uploading, 100GB will get you ~7 hours of video. $___.