Sunday, May 10, 2009

Tabletop Demonstrator

Knot-tying instruction is a difficult subject to film. If you don't believe me, go onto YouTube and just search for knots. The problem is that the easiest angle to film is from the front, but if you try to follow along and tie the knot, everything is in reverse. The best angle for instruction is from the perspective of the knot-tyer. But most videos from that angle are really jerky as someone attaches the camera to their head to get a "point of view" recording.

So I came up with a PVC contraption, originally called the Knot Demonstrator. It allows you to film directly downwards, which works pretty well for filming knot-tying. But then my wife wanted to digitize some artwork that wouldn't fit in the scanner, and we discovered that the Knot Demonstrator works for that, too. So after a lot of experimentation and changes, I've come up with a stable design that allows you to film and photograph anything from directly above. The new name is Tabletop Demonstrator because it can be used for much more than just knot videos.

(All 3/4" sch 40 PVC or fittings)

Legs -- 4x 21.5"
Crossbeams -- 4x 9"
Z-Beams -- 4x 10.5"
Stabilizers -- 2x 7"
Hidden Connectors -- 6x 1.5"
* A note on lengths: These lengths are set up with my specific camera in mind. Depending on how wide of an angle your camera has, you may need to change the dimensions slightly. If, when you have everything set up correctly, you can see any of the PVC, you either need to shorten the legs or make the Z-Beams or Crossbeams longer.

2 End Caps
8 90-degree elbows
8 Tees

By the way, you may notice that there's an extra Tee between the lower crossbeams. I don't know what it's doing there, but it seemed to be a handy place to put a connector (possibly for future modifications).

Price: Around $10.00, unless you have all the parts lying around (like I do)
Build time: 15 minutes, more if you need to adjust the height or width
Availability of materials: Readily available
Durability: It's PVC. Plenty durable for indoor work
Functionality: Works very well for what it's designed for
Portability: Somewhat large and bulky, but it can fold up into a smaller size (see future post)

Saturday, May 9, 2009

Steripen Prefilter

I'm a fan of reusing bottles. I'm using a 1 quart/1 liter Gatorade bottle instead of a Nalgene for holding/purifying my water. I'm terrible at remembering to clean stuff after coming back from a camping trip, and I'd rather a Gatorade bottle go slimy than an expensive "reusable" bottle.

99% of the time, this isn't an issue. My Steripen fits inside the bottle barely, and so I can still use it. As long as the water comes up to the very top, the contacts can be submerged, and the Steripen will operate.

The problem comes when the water isn't deep enough to fill the water up to the top of the bottle. Quick and easy solution is to create a water scooper. This can be made from the bottom of a water or soft drink bottle.
The other problem is that when using a bandanna to filter out guck, you either have to pour the water very slowly or expect to lose most of it off the sides. If you use a funnel, however, the water can take as long as it needs to filter through the bandanna. And fortunately, the top of the same bottle as above can be used as the funnel (see diagram). You simply place the bandanna over the Gatorade bottle, insert the funnel, and then pour water from the scooper into the funnel. It takes a few minutes to fill a 1-liter bottle with this method, but it works. And this would only be needed if the water is cloudy or has floaties.

The final question is, how much space does this take up? Well, if you have external water bottle pockets, I put the funnel at the bottom of the pocket, then my Steripen, and then the scooper upside-down on top of both. It keeps the Steripen from falling out of the pocket as well, so it works great for my usage.

Price: Between one and two dollars for the bottle, plus a bandana
Build time: 5 minutes
Availability of materials: Smart Water is sold everywhere around here; a soft drink bottle would probably work just as well.
Durability: Should last for a while, and it can be rebuilt at any time
Functionality: Works efficiently, if a little slowly
Portability: Fits with the Steripen into a water bottle pocket

Sunday, May 3, 2009

Review: Steripen Adventurer

I've been looking into water purifiers for a long time. It's a pain to have to carry 3 liters of water with me for an overnighter. Half of my gear weight comes from my water. I've looked at filters, but have read horror stories of them clogging or breaking, and the replacement filters can be very expensive. I've looked into chemicals, but some of them taste terrible, and they all take a long time to work. I even considered going with no purification, but that has always made me nervous. I wanted something small, easy, and safe to use that would give instant satisfaction when on a day hike.

Enter the Steripen. The Steripen line of water purifiers use ultraviolet rays to "deactivate" viruses and bacteria (it alters their DNA, so that they can't reproduce). The same thing happens in nature, where the sun purifies water. The appeal of the Steripen is that it's small, usable for years with only replacement batteries, and will purify a liter (quart) of water in 90 seconds. This means that I can go out with almost no gear at all and still drink as much as I want, as long as there's a water source nearby. Plus, I get to connect with nature and taste everything in the stream. That may sound gross, but I'd rather drink what comes from the mountains than what comes through a municipal supply.

Now, on to my review. I can't tell you anything about the effectiveness, since I've never gotten sick with or without water purification. So instead, I'll talk about my impressions.

The Steripen Adventurer is light. According to the official website, the Steripen Adventurer is 3.6 oz. (105 grams) with batteries. That doesn't mean much to me, but it weighs less than half a cup of water. That's pretty light! It also takes up very little space in my pack. It's about the size of a small water bottle, and actually fits in the water bottle pocket of my pack.

It takes CR123 batteries, a common camera battery (they look like half-size AAs). While not as easy to find as AA batteries, any Wal Mart or Target has them. Supposedly, they last for 50 liters or so, which is plenty for an entire season of camping for me.

Using the Steripen is easy. You take off the cap, push the button, and then stick it in the water and stir it for 90 seconds for a liter of water. In practice, it is slightly harder than that for me. For the Steripen to work, the two contact points must be submerged (the little silver oval on the above picture). While this isn't a problem with Nalgene bottles, I'm using a Gatorade bottle, and the contact points barely fit in the mouth. It does work, but the bottle has to be filled up all the way to the top. This is difficult when drawing water from a shallow stream, so I've come with my own system (more on that in another post). Just be aware that if you're using a Gatorade bottle user, you'll need to be able to fill it up to the very rim.

The other thing that makes a Steripen a little more difficult to use is that the water needs to be clear. Murky water blocks the UV rays, making it ineffective. However, I did find some good information in the owner's manual that I hadn't found online. It says it will work with relatively clear water. In their words, it wil work with water that looks like"weak lemonade," the kind that you can still see through, but is slightly cloudy. Plus, with water that is a little more cloudy than this, it suggests using the Steripen twice. And you can always prefilter the water with a bandana, which helps somewhat.

As for construction, the Adventurer seems pretty sturdy. It has a rubbery feel, and is easy to grip when wet. The cap is very secure, to the point where I had a hard time getting it on and off. I don't think I'd want to drop it on the wand when the cap isn't on, as I'm pretty sure it would break, but I think that it could sustain a drop with the cap on. And when in its protective cloth case, I wouldn't be worried about it at all.

All in all, I give it 4.5 out of 5 stars. It loses slight points for needing clear water and the slight difficulty of use in Gatorade bottles. But I still think it's the best solution out there!

Price: $79.95 w/free shipping from
Build time: N/A
Availability of materials: You can buy it online almost anywhere, and I've found it in a couple of local outdoor stores. The batteries aren't hard to find, either.
Durability: As long as you don't drop it with the cap off.
Functionality: Works quickly and easily with clear water; not as good with murky water.
Portability: Will fit in a cargo pocket or on a belt.