Sorry for the radio silence. I had at least three posts planned since just before the holiday started, but let the crazy of the season get the better of me. Fortunately, I've got some new toys to play with and some projects to report on, so all is not lost!
First and foremost, the last STEM club meeting at the school was back just before the school holiday break. Ralph had them making hovercraft this time around, and as could be expected, the balloons were barely contained. (We did lose at least one to the stacks in the library.) Here's a short video of the project.
The concept is simple enough. The air escaping the balloon provides lift through some small holes in the cap on the PVC tube you can see between the balloon and the circular base. A little bit of rotation is applied when the balloon, twisted to keep the air in, is released, and a bit of a push sends it down the table. It was interesting to see how quickly the elasticity of the balloons degraded and how much that affected the performance of the design. I'm not sure what's next on the agenda, but I'm pretty sure Ralph will have them flying something around the library. As always, our thanks to the long-suffering staff of the Fairfax Community Library, and none of this would be possible without Ralph's remarkable efforts to part out all these kits.
The concept is simple enough. The air escaping the balloon provides lift through some small holes in the cap on the PVC tube you can see between the balloon and the circular base. A little bit of rotation is applied when the balloon, twisted to keep the air in, is released, and a bit of a push sends it down the table. It was interesting to see how quickly the elasticity of the balloons degraded and how much that affected the performance of the design. I'm not sure what's next on the agenda, but I'm pretty sure Ralph will have them flying something around the library. As always, our thanks to the long-suffering staff of the Fairfax Community Library, and none of this would be possible without Ralph's remarkable efforts to part out all these kits.
The second thing I'd like to talk about is actually a couple things rolled into one under a larger theme. The two main projects I've got on the bench are the same ones that have been there for an increasingly embarrassing length of time. The 40m direct conversion receiver and the tuning mechanism for the BITX40. I took the 40m receiver and my BitSope Oscilloscope over to Nerd Night at a local IBMer's house where Nerd royalty gathers once a week to break bread(board) together. The good news was that my BitScope was not reading properly and I actually was pretty close to 7MHz with the oscillator circuit. The bad news was that my BitScope was not reading properly. So I've got some research to do and hopefully it's not a lost cause. The BITX40 case is nearly done, and I've assembled the SI5351/Arduino system to act as the Direct Digital Synthesis (DDS) unit for the transceiver. The bad news is that I'm rubbish at arduino coding and applying the scripts I've found online is an exercise in frustration. That brings me to my overarching theme. Failure. The reason why the DC receiver project has been on my desk for so long is that it's not working right. Something's wrong in the circuit somewhere and I'm having trouble nailing it down. The BITX40 would be done by now if I could get that stinking arduino code to work. I keep getting errors in the Integrated Development Environment (IDE) when compiling. That doesn't mean I'm giving up, by any means. It's frustrating, sure, and I've got plenty of projects stuffed away in various corners due to frustration at failed attempts, and there's always another project to try.
It's easy to get discouraged when we see projects on web or see them at a Maker Faire, or magazine somewhere. We generally only see the good stuff. The ones that worked. The plane that flew, or the circuit that didn't explode dramatically (like that electrolytic capacitor that went BANG on me the other day! Fun!). We tend to show off our successes, and we should! They deserve to be to celebrated, but lets celebrate our failures too. That's where things actually make progress anyway, where we really learn. There's a quote attributed to Isaac Asimov that goes something like this:
"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I found it!) but, 'That's funny...'"
Who knows if he actually said it, but I love the sentiment. It's the unexpected result that teaches.
I think next year for Maker Faire I'm going to see if I can get some local nerds to contribute and get together a "Maker Fails" table. Stuff that Did Not Work. I think I'll divide it in two parts, stuff people want suggestions for, and stuff people do not want suggestions for. Maybe I'll have a "Free Failed Experiments!" area too.
73 de KB1VNA
Hi Eric,
ReplyDeleteKeep in mind it is the journey and not the destination. What you are experiencing is what happens with group grope development of hardware and software. I use IDE 1.0.5 because many of the libraries work well with this ancient history IDE (now at 1.6.7). While the IDE's have moved on the libraries haven't. I can write a sketch in 1.0.5 and it will compile and load onto a device. Move the same code over to 1.6.3 (which I have on a second machine) and it won't compile. So I know well what you speak. Bill N2COR offered some really great advice get the DCR working and understand the elements, bit and pieces and then move up. Actually if you use he Varactor Tuned Oscillator that came with the early kits you should be able to get your Bitx40 working without having the Arduino part working. But in VU3ESE's latest kit--it all comes working! So you won't have to mess with the code or IDE's. Think about the journey. The Bitx40 is an experimenter's platform! It allows you to explore and make changes and implement a variety of hacks that are homebrew. You might check out my blog for Bitx40 info http://n6qw.blogspot.com and you will see some of the hacks I have installed. Also go to http://www.n6qw.com/Bitx40.html where I created a tutorial on how to take the radio as it comes from VU3ESE and install it in a box. There is some info on the use of a AD9850 DDS. Oh that is a piece of info for you. The AD9850 is a DDS device whereas the Si5351 is a Phase Locked Loop Clock Generator. The difference is that with the DDS you get a sine wave output and the Si5351 is more like square waves as you would get from a TTL clock oscillator.
Good Luck --it is the Journey!
73's
Pete N6QW
Wow, first Bill Meara and now the one and only Pete Juliano! I'm honored!
DeleteThanks for the comments and corrections. I do actually have a spare eBay AD9850 and another Arduino nano kicking around. I'll have to put them together at some point. I know the varactor method works out of the box, I just wanted to try this method out after hearing you guys talk it up so much. I will definitely check out your links.
You're absolutely right about the journey aspect of the hobby. When I think about what I want to teach to my kids this is a very big part of it. There's a bit of an art to "getting there."
73 de KB1VNA