I picked up a CX10 mini quadcopter on eBay. The CX10 is a tiny, 50mm quadcopter that costs around 10GBP (~15USD). Apparently they work reasonably well (but mine came pre-broken which is always handy).
There’s an interesting teardown over on the EEVBlog forums. The design seems quite nice. It uses an STM32 with a 2.4GHz receiver and 3 axis gyro/accelerometer.
The motors look like standard pager style motors. I believe these are standard brushed DC motors, but it’s possible they are coreless.
The simplicity of the design got me thinking. It turns out the rotors are available separately (as are the bare boards actually, see left). So I started wondering about how I might go about designing one. As a first step I measured the quadcopter and put the above design for a frame together (design files below). I’ve sent it out to dirtySLA (which cost a massive 4USD! :)) for fabrication.
I’ve revised the PunkSeq10 schematics to fix an error (amazingly I’d managed to leave the 4017s supply unconnected!). This revision also adds switches which allow selection between 4,8 or 10 steps. I’ve tidied up the silk a little, and added some mounting holes.
I’ve ordered a set of these gerbers, and you can order the PCB, a complete set of components and build guide here.
For the past few months I’ve been writing for Hackaday. There are two types of article on Hackaday, the regular daily reports of user submitted projects and featured articles. I’ve wrote a few of both, but have mostly been sticking to featured articles recently. It’s been an interesting experience, and has providing an insight into the dynamics of a high traffic blog.
In some ways I think I’m not a particularly good writer. I choose subjects based on whether I find (not the reader) them interesting or not. An case in point is my last article on adhesive tape. I’m basically interested in tape, different kinds of tape, how I can better use it in my lab and its sometimes surprising physical properties (did you know tape lights up in the dark?). I figured it was reasonably unlikely that a large number of people were also interested in tape… surprisingly though the article did pretty well.
From a blogging perspective I think this is a poor strategy though. I actively avoid writing about current events, which would most likely gain me far more comments (which is how I evaluate the success of an article). There are a few reasons for this… The first is that I think it’s unlikely I’d have anything new to add, I’d just be repeating what I’d seen elsewhere and adding my own viewpoint. The second is current events rarely interest me, N=1 incidents such as Ahmeds clock I find mildly infuriating as I see an incident take on meme like properties low on information, but high on speculation and supposition. The same can often be said of technical advancements, when only a press release is available the void is often filed by opinion and imagination.
Another great way to prompt a response from the reader is to put forward a contentious opinion. I also tend to avoid this. I think because I’m mostly a live and let live kind of guy (or to put it another way, I don’t like to be told what to do). So I prefer to try and somewhat rationally layout the pros and cons.
Sometimes I get drawn into controversy unintentionally though, like in an article I wrote on Forrest Mims. Forrest Mims is pretty well known for his electronics books and articles, but less well known for some of his scientific publications. The fact that he’s made a concerted effort to publish his amateur science efforts in peer reviewed publications I found really interesting. I searched around for other people how had done the same thing and basically came up empty. So I wrote an article on his use of LEDs as light sensors and the article he wrote with his daughter on fungal spore migration. I had no idea what a shitstorm that would turn into.
Thing is, Mims isn’t a huge fan of evolution or climate change and he’s a somewhat hardcore Christian. I carefully avoid those issues when writing the article because I didn’t think his personal beliefs were relevant. In fact by mentioning them I would only be further his ends, because Mims has sort media attention on these issues in the past.
So I was hoping to put those issues to one side, and talk about the science and technology. Dave Jones (of eevblog fame) is pretty vocally anti-religion, but when he interviewed Mims on the Amp hour I was impressed that he was able to discuss his scientific and engineering work without getting into the “whole religion thing”. That wasn’t the case for this, I thought relatively innocuous, article. The comment thread turn into something of a literal religious war. The article attracted 139 comments, more than any of my other articles.
As I said before, I’m not one to try and write articles that people actually want to read… but if I was I take this as a sure sign to write controversial articles like this and generate “more heat than light” arguments. I wonder if commenters are aware of this dynamic…
There’s a lot more I could write on writing, and what an amazingly a painful process it is for a compsci/engineer like me, though a hugely valuable one. But I think I’ll leave it at that for now. Look out for more posts in the future!