Monday, August 18, 2008

A quick update

It's been a while since I've posted so I thought I'd give a quick update on happenings here.

Everyone is happy and well. The kids are starting school soon. I think we're looking forward to that more than they are. With the exception of Adam. He was rather disappointed when Kindergarten was over and he didn't get to start 1st grade right away. I guess we never explained about summer vacation and just assumed he knew about it.

We're also in the planning stages for a trip to Walt Disney World. It's been 12 years since we've been there. And 3 years since I've been to Disneyland. It's killing me. I need my Disney park fix!

If you followed along on my last geek post from a few months ago here's a brief follow-up:

1) I finished the motion flash and it turned out really well. My friend was giddy with excitement when I turned it in to him. I should probably post the documentation for it just for posterity and geeky completeness.

2) The donor laptop for my photo frame died. So that project is dead until I can find another. It was on it's last legs anyway. Then one day it booted up but wasn't finding the wireless network. When I tried to fix that it just wouldn't boot at all. So I did what anyone else would do and took it apart. ;) I'm sure some of its guts will make for another interesting project someday (if they don't make it to the electronics recyclers first).

3 & 4) The hacked router and NSLU2 are humming along just fine. Nice and stable. If it wasn't for the occasional power outages we've been having recently they wouldn't have had any downtime since I first got them up and running. And they've survived some of my own mistakes as well too. I'm really liking them.

5) My other server has been painted a nice dark forest green to blend in well with the wall behind my office desk. It got a newer, heftier, quieter, and more efficient power supply. So it's running along very stealthily. I still haven't installed the raid array though, so it's not serving as a NAS just yet.

I got a great deal on Windows Server 2003 (free, and it's 100% legal!) So it's running Windows Server right now instead of Linux. On that same deal I also got a (free and legal) copy of Visual Studio so I'm teaching myself C# and nudging David along to do the same. He's reluctant and I can't really understand why. I think it's because he's still in summer mode and doesn't want to pick up any books. Anyway, the server is also running Folding@Home, so it's idle time is at least taken up to doing some good.

6) The rocket cam has been at a stand-still as I've been using what free-time I have for more Linux tinkering, C# learning, and I've even taken up some reading. (Gasp!) I did get the camera mounted into the nosecone though. I just need to wire up a different battery, poke a hole so it can see out, and mount a mirror so it can be looking downward. Not a whole lot and I should probably finish it up before the weather turns bad for another 9 months of rain and clouds (welcome to the Pacific Northwest). I guess I should try to knock that project out this week since I have the time and there really isn't a whole lot left to do.

Friday, April 18, 2008

Geeky fun

Warning: Lots of geek content follows. Feel free to read anyway, but if you're not a geek or don't have one nearby, I hope you brought your own flotation device.

I've rediscovered an old hobby: taking things apart. Also known as "hacking," but these days that word has certain negative connotations. This hobby of mine is what originally got me interested in engineering. As an engineer I had daily opportunities to hack and design many projects. It was great fun. I even tackled many DIY projects at home just for the fun of it. But now that my career has taken a different path I no longer have the daily opportunities to work my hands and mind in that way. So, I've been finding ways at home, as time and budget allows, to fill that void.

Last year I built a MAME arcade cabinet. That didn't require much "hacking" as I didn't repurpose or reuse old hardware other than a used computer I bought off Craigslist. Everything else that went into it was purchased or built new. That was a really fun project. I put the finishing touches on it a couple months ago when I installed a coin door (that I now need to wire up for lighting). So it's also (optionally) coin operated.

So now that that project is done I'm moving on to others. Here's what I've currently got on my plate:

1. A friend at work has been wanting a motion activated flash (as in, camera flash). He plans to use it to scare off would-be home intruders/snoopers. It might be a little paranoid of him, but it's a fun project (that I don't have to pay for) that he asked me to take on. So I got a couple free used disposable cameras from Walgreens, took them apart, and have been figuring out ways to get them to work with a motion sensor he provided. I've had my eye on a new toy called the Arduino and this looked like the perfect project to use it on.

The Arduino is a great little gadget. I've finished programming it and so far I haven't fried it. I've been having a little trouble figuring out the proper circuit design to trigger the flash from the Arduino's output signal. I think I've finally found the solution thanks to a similar project. The flash trigger uses a capacitor that discharges so quickly and with so much current that it would fry the Arduino so a relay switch needs to be used. I was trying to use a reed relay switch from RadioShack, but it kept sticking due to microwelding on the contacts. I just ordered the optoisolator used in that other project. If it works out then the prototype will be all finished.

2. I mentioned to another friend of mine that I've been looking for a donor laptop that I can turn into a digital picture frame. He just happened to have a laptop he was going to get rid of and gave it to me. The most time intense part of this project will be building the frame, which I just haven't gotten around to yet. But I have been tinkering around with testing various software options. It currently has Windows XP installed, but I don't like any of the slideshow options available to XP. Instead, I'm thinking of using Mythbuntu, or some other variation of MythTV. It has a lot more capability than I would need. But the parts I will use I do like very much. Ha, maybe I'll just get really geeky and write my own software. Isn't that what a real hacker would do anyway?

So this project sort of paved the way for other projects...

3. I needed a wireless router for use with the digital picture frame, and for other general wifi fun (ie Nintendo DS, etc.) I had heard about how the Linksys WRT54GL uses opensource firmware and that the opensource community had created new and better firmware for it called DD-WRT. So I bought a Linksys router and flashed the firmware to DD-WRT. Was it absolutely necessary to change the firmware? No. I could have left it as is and been fine, but why not make something good even better? Especially when it's a free upgrade! I haven't done much with the new capabilities DD-WRT brings other than boost the wireless signal strength. But I also haven't had enough time to learn about and implement any of the other new capabilities.

4. Having one "hacked" Linksys product just isn't enough though. At the time I learned about DD-WRT I also learned about a cool little device called the NSLU2 or "slug." It's a tiny computer you can attach 1 or 2 external drives to and have "instant" network attached storage. Seeing as I was going to need a place on the network to store photos to be displayed on the digital frame, and I didn't want to use our main computer (which is quickly running out of space anyway), this would be the perfect solution. It's silent, uses very little power, takes up very little space,'s "upgradeable" too. I flashed the firmware and installed the Debian distribution of linux on it.

This has been the more challenging project because the NSLU2 doesn't have a graphical display. I have to SSH into it and use linux command lines to install and configure various software. So it's been a fun learning experience. So far I've got it sharing folders on the network using samba. It's running a web server (apache, php4, and mySQL) that isn't really doing anything note worthy yet. I even have it running a music server. I had it streaming music to me at work from home the other day. I've since disabled external access to the music server though because I don't want the RIAA knocking down my door. I'll have it enabled again once I do some additional configuration to lock it down securely. And no, I'm not going to post a link to it. I don't want a web spider to find it and have the scary kind of hackers testing its limits.

(Don't leave yet. There's more.)

5. I have given David the opportunity to earn a computer of his own. In Portland there is a computer recycling place called Free Geek. If you donate 24 hours of volunteer work for them they give you a computer. It's not a new, powerful computer. But it's not bad either. It's probably worth only about $100 so you're only getting "paid" about $4/hour. But it's for a good cause. They're a great company and are doing great things in the area of computer reuse and recycling. So David and I put in a few Saturdays' work and have each earned a computer. We'll be picking them up tomorrow.

On a side note, Tammie and I aren't quite sure about how sure we are in letting David have a computer (if that makes sense). So we'll be monitoring very closely. It's kind of a pilot program for us. We're testing the waters. I'll be putting some network monitoring tools in place and we'll see how things go. I'm hoping that this will be a good learning experience and tool for him and not just a distraction or a danger. There is much good that can come from it, but an equal amount of harm.

But my's going to be given a raid array and become a very large network attached storage and backup server. Also, another toy to use to tinker and learn linux.

(Are you still here?)

6. I recently subscribed to a quarterly magazine called Make and I read their blog on a daily basis. (For those of you into crafts you might want to check out their sister publication Craft and the Craft blog.) They feature projects for home brew technology and give lots of ideas to people like me. One such idea that I'm now running with is putting a one-time use camera into a model rocket. This involves stripping down the camera to save weight and hacking it to make it possible to download the videos to your computer and reuse the camera. I've already assembled the rocket. I'm just waiting for some parts to arrive (free samples!) in the mail for use in hacking the camera. If I can do it well I'd like to buy more of these cameras for the kids to use for shooting their own videos on vacation or just for fun. So stay tuned in the coming months for some rocket cam videos!

That's it for now. I'm sure there will be more as I keep reading Make and the Make blog. In fact, today I just read about another fun project with kitchen vacuum forming. I try to find projects that can involve the kids. David's having fun following along with my computer exploits. Adam is excited about this rocket. I think Rachel will love vacuum forming.

Sunday, March 2, 2008

Telescopes: Getting started

In a comment to my last post, Summer asked about some suggestions for telescopes. Since other's may be interested too, instead of answering her by email I'll just post the information here.


There are 2 basic types of telescopes to consider. Refracting and reflecting. (There is a 3rd that combines the 2 concepts called Schmidt-Cassegrain.)

Refracting telescopes are the ones that people typically think of when they think "telescope." They contain a series of lenses stacked inside a tube.

This one is an example of a refracting telescope. Low cost refracting scopes can be good for looking at the moon, planets, star clusters, and near galaxies. High cost ones can offer greater clarity but come at a very high cost for good optics.

The downside of refracting scopes is size. They are long and often have a small diameter lens. Longer telescopes are little more cumbersome to store, transport, and set up. Small diameter scopes mean less light gets in so deep sky objects (or dim objects) are much harder to see.

A reflecting telescope uses a series of mirrors instead of lenses to bounce the image through the tube and focus it in the eyepiece. These types can be shorter without sacrificing focal length and offer a much larger diameter for capturing more light.

The downside to reflecting telescopes is the image gets flipped upside-down when you view it. So aligning objects in the eyepiece can be a little tricky at first until you get used to it. Left is right and up is down. (The trick is, instead of thinking about moving the telescope, think about moving the object. If the moon is too far to the left then instead of moving the telescope to the left, move the moon to the right.) So, a flipped image, not that big of a deal, unless you also want to use this telescope for terrestrial viewing. That is, observing animals or far-away objects on earth. A refracting telescope image will be oriented correctly.

Most reflectors have an open tube design that is subject to gathering dust, dew, or other junk on the mirrors that will degrade the quality of the image and may need to be cleaned if dirty. Cleaning these optics can be very tricky as it usually requires disassembly. And disassembly means reassembly which is even more tricky and requires special tools to align or collimate the optics. They all come with dust caps though, so keeping them covered when not in use and being careful outdoors to not use in a very dusty area will keep things clean for a long time.


If you want to gather a lot of light you need a large diameter lens or mirror. The larger the diameter the more light that gets collected and the brighter the objects. With more light you can see nebulae better and galaxies really pop. Also, the larger the diameter the larger the useful magnification. Meaning you get more detail at larger magnifications.

Focal length is used to determine how large the objects will appear through the eyepiece. The larger the focal length the larger the object. Eyepieces also have a focal length that works just the opposite. The "smaller" the eyepiece the larger the object. You can calculate the magnification by just dividing the telescope focal length by the eyepiece focal length. For example: a 700mm focal length will have a 28x magnification (28 times bigger than viewing with the naked eye) when using a 25mm lens (700mm/25mm=28x) or a 70x magnification with a 10mm lens (700mm/10mm=70x). A 350mm focal length would have half the magnification potential of 700mm with the same eyepieces (350mm/25mm=14x).

Motorized mounts

A motorized mount is great for a beginner. They typically come with a simple hand-held computerized keypad that can find objects for you. If set up accurately you don't have to know where Saturn or Andromeda are to be able to find them. They also can continuously move the scope for you to track the movement of the sky. (Yes, it's the earth that is rotating, but from the perspective of the viewer it's the sky that's moving.) And at high magnifications the objects can move out of the eyepiece very rapidly. The on-board computer can also take you on a sky tour and show you things you may not have previously known about.

However, motor mounts can really cause the price to jump. They also can take some time and finesse to set up. The computer needs to get everything aligned before it can accurately find objects and reliably track them. This can be fun or frustrating depending on your personality. The tripod needs to be leveled. Then the scope gets leveled and aimed north. Then you begin the alignment by entering the time and date, location on earth (nearest city or lat/long), and aligning to 2 stars. If done right and if the batteries are fresh it can make for a great night of viewing. But if done wrong or your batteries begin to die (and they do eat through batteries in just a few nights) it can quickly lead to frustration and packing things up early.

Telescopes without a motor mount do force you to learn the sky though, and that can be very beneficial to having a good time without the extra complicated setup or relying on battery power.

Some telescopes that don't come with a motor mount can sometimes be upgraded by buying the mount separately. This is not typical though. So if this is something you want to do to spread out the starting expense then be very careful to see if this is an option for the scope you are interested in.


The bare minimum accessories that I recommend for a beginner are:

25mm eyepiece (most scopes come with this)
10mm eyepiece
Barlow lens (this doubles the magnification of any eyepiece)
Lunar filter (cuts the glare and gives greater contrast)
A star chart, the very simple and cheap rotating type
A field guide to astronomy
A protective case for storage and transport (many scopes just come packed in styrofoam and cardboard and this is not suitable for constant use)
A flashlight with a red filter (so you can see in the dark without affecting your night vision)

There are many other filters available and can be bought individually or in a pack. Color filters are good for bringing out planetary, nebula, or galaxy details. A light pollution filter is good to filter out the wavelength of light typical to city lights. A solar filter is a must for any viewing of sun spots or solar eclipse. (Most filters screw on to the eyepiece, but solar filters attach to the outside of the telescope where the light enters. This protects the optics from getting damaged by the heat of the sun.)

If your scope can handle the higher magnification then a 3.5mm eyepiece is also good to have.

Purchasing accessories can really break the bank though, so keep them in mind when setting your budget.

Other notable things

I recommend sticking to well known names (Orion, Celestron, Meade, Edmund Scientific).

Make sure the eyepiece tube of any scope you buy takes a standard eyepiece size of 1.25" or 2". The 1.25" size is typical for most scopes and has more and affordable accessories.

Wednesday, February 20, 2008

A Total Eclipse of the Moon

We actually had a cloudless night here in Portland for the lunar eclipse. I got my telescope out and tried a little astrophotography (holding my camera by hand to the telescope eyepiece).

Here's the eclipsed moon at totality:

Coming out of the eclipse:

Not the greatest pictures, but not too bad considering I had to hold the camera by hand.

I'd like to get one of these to make it easier to take pictures...

We also got to look at Saturn, which was really cool, considering I had never seen it through my telescope before.