Our lonely little circuit board now has 511 friends and Light Night is fast approaching. Construction continues.
It doesn’t look much does it? How could something this mundane unleash such huge amounts of awesome?
Keep watching to find out!
Since both the hackspace, and my home are fairly close to the approach to Leeds/Bradford airport, and I’ve always had an interest in aircraft I’ve often wondered what was flying around, so decided that building my own virtual radar system would be an interesting project.
Having previously experimented with using a USB tv tuner as a software defined radio I settled on a Beaglebone Black and E4000 tuner (very inexpensive, available on ebay). The required software is rtl-sdr (a library for using the tv tuner as a software defined radio) and dump1090 (which uses rtl-sdr to decode the aircraft broadcasts).
A quiet tuesday evening with little air traffic.
Having installed debian on a spare micro SD card and compiled the software a quick test with the aerial included with the tv tuner proved that the whole setup worked and was happily picking up aircraft approaching the airport, the next step was a better aerial. I opted for a colinear aerial, which can be constructed from nothing more than a length of coaxial cable and some tape to hold it together. Construction details can be found here. The finished aerial was sealed into a length of 21.5mm overflow pipe to avoid water getting into the coax and affecting reception.
Performance with the new aerial is much improved, and gives a range of approximately 100 miles with the aerial simply placed on a roof. Range is approximately halved if the aerial is mounted internally. Hopefully a range improvement can be gained when the aerial is properly mounted above the roofline.
Scatter plot of aircraft positions.
Using an improved version of the dump1090 software with integrated mysql logging gives a number of additional possibilities, a scatter plot of the logged tracks nicely shows the routes in use. Adding extra tables to the database schema to hold aircraft information can allow you to search flights on aircraft type and owner/operator, revealing interesting patterns in the users of UK airspace.
Aircraft data mapped to icao24 identifiers.
Future improvements include better aerial positioning, the possible addition of extra receiver nodes, and a high gain directional yagi aerial allowing longer range reception in any direction of interest (based on a design from this yagi calculator – details will be provided in a future blog post).
A quick reminder: There is a workshop ongoing at Leeds Hackspace tomorrow 1330- 1630. The space hasn’t been closed to other members during that time but other members are asked to try not to interfere/ disrupt the workshop and as ever please see rule 1. Thank you.
I wanted to 3D print a part for a remote control car, I had recovered it from a skip from the back of my house and someone had super glued the steering to a metal shaft connected to one of the wheels and that shaft was meant to move freely. It had broken.
Sure there are simpler solutions than 3D printing a part, but being a member of Leeds Hackspace with a MendelMax readily available I figured this was a good time to learn. So my next problem was getting the model from meatspace into cyberspace.
So there’s two choices, I either 3D model the piece of plastic by hand, using OpenSCAD, Blender, 3DStudio Max, etc. Though there are two problems to that. One is that some of the software costs money I don’t have, the other is I don’t know how to use them. Especially Blender, ugh. Or I 3D scan the plastic to mitigate the majority of the modelling and just alter it afterwards, which is possibly harder but the thought of tinkering with electronics and distracting myself from learning a 3D package was too tempting.
3D scanners are expensive. You can get fancy hand-held ones for $900, I’ll let you do the Google search. So I wanted to make my own, why not?
I have no idea what I’m doing
I have no idea what I’m doing, after talking with a number of people from the Hackspace the best idea was to go with a laser and webcam combination. At this stage I was interested in what was available for free on the internet to use as a basis for making a 3D scanner. So I searched off for software, in the Hackspace I have sufficient hardware to do the job, a member bought a bag of 50 lasers with the intention of attaching them to everything (why not?) and constructed some laser-sights for nerf guns (the maverick in particular).
The webcam we had left over from the Hackspace versus Pumping Station 1 competition with the Beaglebone Black in 2013, a Playstation Eye from the PS3. So I felt that I was off to a good start.
After searching online for a while, I happened upon MakerScanner, free open source software that’s available on github, low and behold it also uses a PSEye and laser, even better is that it has the parts/frame available as a thingiverse download.
The software, written in C++ is painless to download and compile if you’re running linux. I run Debian Wheezy on my personal laptop, so visiting the github , downloading a zip (there should be a button for it) rather than cloning the git repository made it even simpler. Extract, follow the instructions on the page, run.
I had a problem, I had a laser pointer, but I needed the laser in a form that was useful; a line. Similar to what you get from a barcode scanner at the supermarket. White-tac and a bar of metal which was recovered from a printer came to the rescue!
 Laser mounted white-tac! |
 Beam test |
When the laser was shone at the metal bar at about 45 degrees, the reflection was a nice, sharp, clear line. After trying it by hand, the white-tac was piled up to support it. What you can also see in the photo is that the white-tac was affixed on top of a bolt, that was sat within some metal rings (actually bearings if I recall correctly) just so that we could rotate it in situ. It wasn’t graceful, but it worked!
 Scanning! |
 Scanned! |
Suffice to say, I did get readings. MakerScanner creates an RGB coloured point cloud from the scan, but I also had a lot of noise in the scan. I attribute this mainly to the scatter of the laser from the metal bar, which if I was to use in future then I would put a filter on it to ensure a clean line. Though I would ideally get hold of a proper lens that should produce the same output. The other reason for the noise was partly reflections from the table surface I was scanning on, the paper helped with this.
However there was still a lot of mess on the point cloud, by mess I don’t mean scattering but it appeared that some points were either being misplaced or calculated incorrectly. I couldn’t tell if this was in software or if it was just dodgy hardware.
I think that I need to narrow down my variables and try to acquire some decent pieces, though I don’t have a lot of money to do so! I think being self contained would be useful, but having seen some hand-held 3D scanners then I’d rather go in that direction.
And yes I did just use an Arduino to power the laser, lazily.
Any feedback/questions appreciated.
Last weekend we went to the UK Maker Faire and saw many awesome things, including some very nice LED cubes. Inspired by this I thought I’d have a go at building a small one.
Constructing the cube itself was relatively straightforward. The structure is formed almost entirely from the legs of the LEDs. The anode legs are bent 90° to form a strip of 4 LEDs. The cathode drops down to meet the anode rail of the strip below, which is rotated 90° to give an alternating grid of anode/cathode wires. The whole assembly is mounted on a piece of stripboard (forming the cathode connections for the bottom row of LEDs), along with vertcal wires to drop down the anode rails.
This results in a charliplexed matrix, requiring 12 drive wires. Effectively it’s an 8×4 grid with two LEDs (one of each polarity) at each intersection. This is connected directly to an Arduino Pro Micro (a small form-factor variant of an Arduino Leonardo).
I’ve already written a charlieplex driver for a different project, so a bit of modification and a few re-soldered joints later I had a working LED cube. Not bad for an afternoon’s work!
However initial results were poor. I’d used some cheap blue LEDs I happened to have left over. These are nice and bright, but with water clear cases and fairly narrow focus. Unless you were looking almost directly down it was barely visible. In fact each LED illuminated the LED immediately above more than it lit itself. In the video this is particularly noticable on the vertical sweep (and the reason I didn’t bother make it sweep back down!).
The solution was to put a small blob of hot glue on top of each LED. This dries slightly opaque, forming a near perfect diffuser!
This weekend at the hackspace I realised that my personal 3D printer needed a part that we made for the space printer using the laser cutter.
Unfortunately the laser cutter is no longer with us and it was a little bit of a bodge. Â Enter the now working 3D printer!
I actually designed and printed the part on our existing printer from scratch, and here is the part being printed and the final version.
Saturday 12th April 2014 – 11am till 4pm
Myself and a few other members are opening the Hackspace on saturday for an open-day; we’ve had people ask if someone would open the space on a not-tuesday and this’s the result!
Bring yourself down, have a chat, bring a project, discuss a project, or don’t have a project and just check out the people and the space and chillax for a few!
See you there?
Hello everyone,
The directors have been contacted on at least two occasions about developing a small scale partnership with Forward3D; these people are working with Premier Farnell/element14 to help create more content for the site(s) and generally get feedback on stuff that we sell at the company (yes, I work for element14, too, coincidentally).
So I’ve been talking with Forward3D (because I hadn’t heard of them before, but they are genuine as I checked with the Farnell Marketing team) and they need to know if there are any specific components that would help with any workshops, projects or otherwise that people are working on?
This isn’t something to be passed up or ignored and I think this would be a lost opportunity if it isn’t taken up. So even if you are just spending an hour a week to get something done, or if you need some parts to get the rest of your work complete, it’d be a good idea to mention/list/feed back to me what you need/want.
Let me know, here, in person or e-mail or on the mailing list (https://groups.google.com/forum/#!topic/leeds-hack-space/GJ_7INY_5kw) as soon as you can.
Forward3D are also contacting other Hackspaces in the UK to try to develop something more national in the future.
Today we learned a lesson in quality control. And how little some suppliers have.
We recently bought a set of (very) cheap “stepstick” 3D printer stepper motor drivers. While attaching heatsinks we noticed one board wasn’t mounting correctly. Further invstigation revealed that one of the components wasn’t quite soldered in the correct position:
Easily fixed with a quick dab of a soldering iron.
