After having not touched the bluetooth-serial interface I built for over a year, I pulled it out of the drawer recently and found it to be dead–specifically, the BT2S module. Seeing that a replacement was going to be $17.95 plus shipping, I began looking for alternatives. I selected the BT2S specifically because it worked at +5V voltage levels. There are a number of similar-looking modules on EBay that sell for much less, but they all use +3.3V supply and logic levels (search for HC-06 on EBay and you’ll see what I’m talking about). Could my circuit be converted to run at 3.3V?
It turns out the answer is yes. It appears that I can replace the MAX232 chip with a MAX3232, the 78L05 voltage regulator with a 78L33 3.3V regulator, and the BT2S with one of the HC-06 modules from EBay. No changes to the circuit board are needed. That’ll cut the cost of the project by a good chunk. I have the parts on order now to test it for myself, and then (assuming success) I’ll update the project page.
Here’s an image I took with my NexStar 6SE and Canon EOS Digital Rebel XT DSLR of the total lunar eclipse on the evening of 27 Sept 2015, just after the eclipse reached totality. The image was taken with the DSLR mounted at the prime focus of the NexStar 6SE. This is a 1500-mm f/10 setup, with the camera set at ISO 400, 15-sec exposure. Unfortunately, with the long focal length I couldn’t quite fit the entire moon in the frame.
I seem to be getting into the habit of acquiring older gear and then facing the uphill battle of making it work with more modern equipment. Recently, I wandered into the local pawn shop here in Woodland Park and discovered a used Canon EOS Digital Rebel XT (350D) DSLR camera sitting on the shelf. I’d always wanted a DSLR with which to try some astro-imaging but wasn’t willing to shell out the bucks for a new one. So, I laid out the cash and took the 350D home with me to check it out.
Did I mention that we moved from Colorado Springs to Woodland Park this spring? We found ourselves a nice house on an acre with mostly dark skies overhead. You can actually see the Milky Way on moonless nights–completely unlike the washed out urban sky in Colorado Springs. We love it! If you noticed that there haven’t been any additions to the ol’ web site for more than a year, now you know why. It’s a lot of work to get one house ready for sale, sell it, find a new house, buy it, and get moved. I’m pooped. Anyway, let me tell you a little bit about the new camera and what it took to get things up and running.
One of the things that intrigued me about my new Elecraft KX3 is that it has a built-in serial interface (the ACC1 port). I thought it might be a fun project to see if I could interface it with my Google Nexus 7 Android tablet via bluetooth, reminiscent of my old GOLog project with the Serial Sender. I couldn’t find much in the way of Android apps that would interface to the KX3 in a useful way, but I decided to put together a bluetooth-serial interface and then see if I could write an app of my own that might be handy for, say, SOTA activations and Field Day.
Although I haven’t gotten anywhere yet with writing my own Android app, I did come up with a bluetooth serial interface that works with the KX3. The detailed project description is here. A PC board is available from FAR Circuits, and the project is designed to fit nicely into an enclosure with a built-in 9V battery compartment.
So, you probably saw the post I put up a day or two ago about having just gotten a Celestron NexStar 6SE telescope. I’ve been having a ball with it so far. My plan last night was to try using my digital camera to take some video of Jupiter and then run it through Registax software to see what came out of it. I followed the instructions posted on this page at Stargazer’s Lounge. I can’t claim to have done anything original here–just followed the cookbook.
I’ve never been crazy about my Meade Starfinder 8″ equatorial Newtonian telescope. The optics seem fine, but the mount is heavy, hard to move, and hard to use. Even with my digital setting circles it’s difficult to get the thing pointed exactly where you want it, and a modest breeze can make it almost unusable. Even getting it set up was a chore. So I didn’t really use it much, and I felt bad about that. So, a week ago I decided to buy myself a new telescope, and this time I chose something much more compact–a Celestron NexStar 6SE SCT.
Who among the backpacking crowd hasn’t wished for a more manageable way to carry a decent camera on the trail? I carried a little pocket digital camera for many years but was never really happy with the pictures I was getting. I really longed for a better quality camera–one with decent optics, versatile optical zoom, capable of taking pictures under various lighting conditions, etc. But it’s a challenge to carry anything bigger than a pocket-sized camera on the trail. Where do you put it so it’s not either always in your hands or bouncing against you at the end of its strap? Continue reading →
If you’re a backpacker or hiker and you’ve been looking for a way to strap your HT to your backpack within easy reach, you might be interested in a pouch I found for my VX-8GR. Almost every HT these days comes with a belt clip, but on the trail it’s easy to knock something like that off your belt and either break it or lose it. I’ve always wanted something more secure, that also puts the HT up on my backpack shoulder strap where it’s easy to access. It turns out that the makers of tactical (military) equipment are putting out some pretty neat stuff these days, and I found this pouch from Condor:
I bought mine for about ten bucks from Ebay, but you can get them from a variety of sources for about the same price. It comes in multiple colors. If you look at the picture, you can see that it includes an elastic drawstring and cord lock. These allow you to cinch down the pouch if needed to keep the radio in place. In the case of my VX-8GR, the pouch fits pretty well without the drawstring and cord lock. The velcro flap that goes over the top of the radio (around the antenna) will hold the radio pretty securely by itself.
The only challenge left is how to secure the radio/pouch to a backpack shoulder strap. The pouch itself has a belt loop on the back with a snap. I plan to fashion a “belt” for it to hook to using some Velcro One-Wrap wrapped around the width of the shoulder strap. I’m still waiting for the Velcro to show up, but I’m pretty sure this will give me a pretty solid and secure attachment for my HT.
So, it turns out that a backpack strap isn’t a good attachment point for an HT, at least in my case. There’s just no good place to attach the HT where it isn’t in the way or just plain awkward. The good news is that the pouch’s belt loop (really a Molle attachment strap) is just the right size to snap over the hip belt on my backpacks. That ended up being a perfect spot for it, and still very secure.
I just posted another of my quick reference card creations–this time for the Yaesu VX-8GR. It’s a great little HT packed with tons of features, but if you’re getting a little older like me, it gets harder to remember how to use all those features if you don’t use the radio often enough. Anyway, mine’s designed as a quick reference to things I’d need to do on the trail, and it doesn’t encompass everything that the radio can do. I share it here in case it’s useful to anyone else.
Did I mention that I just received my new Elecraft KX3 (#5522) ham transceiver? Wonderful rig (but more on that in another post). The KX3 ships with your choice of a USB cable or a serial cable for interfacing with your PC. With either of these cables, you can use Elecraft’s KX3 Utility software to update the KX3’s firmware, or you can otherwise control the rig with suitable software (say, Ham Radio Deluxe) running on your PC. At any rate, I received the USB cable with my KX3.
I’m interested to see if I can rig up a bluetooth connection between my KX3 and my Android tablet, though, and it seemed that a good place to start would be to fabricate a serial cable, to which I could ultimately connect a serial-to-bluetooth adapter of some sort. Here’s how I did it.