I was wondering what the technique is called that you used on the K matrix before solving for U?
The one where it takes the BC and makes 0 rows and columns, and then makes the K(i,i)=1 at the BC – GoPDemon
With a cupboard full of old hard drives and some spare time, I recently set about making a persistence of vision clock. Using the platter of a hard disk, a slot is cut to allow backlighting to be emit. When the disk is spinning at 5400rpm+ and backlight constant, the disk appears opaque, as the slit is ‘refreshing’ each point of the revolution faster than our eyes. The trick is to measure the revolution time then flash or change the backlight colour at a fraction of this revolution time at the same point each revolution, in order to create a light segment. For example, flashing the light at a frequency twelve times the disk frequency in phase with the disk will create 12 light segments:
Expanding on this, one can create a light based clock, which takes some getting one’s head around on first sight!
Why Replace My 2006 MacBook HDD with SSD
My MacBook is the 2006 original; the white Core Duo 32bit. I got it upon starting University and that ended up taking six years. Amazingly, it is still going strong and whilst I want a nice retina MBP, it would be truly frivolous, given how well this one still runs.
Over the years I have given it a number of upgrades: 70GB > 500GB HDD, 512MB > 2GB (max for Core Duo) ram, new battery and a complimentary top deck from Apple (long story). Now I was turning to an SSD.
Now Arch isn’t exactly plug and play, but that’s part of the fun. Plugging it in, the only way you’ll know it is there is using:
Continue reading Setting Up a USB WiFi Dongle on Raspberry Pi Arch
Those little window sucker things for GPSes and cables dangling everywhere get on my tits. Since getting the van, I’ve been intending a dash integration of sorts, whether completely containing a GPS unit, or building a CarPC with my Raspberry Pi, it was put on hold until I had some time. With the race season over and Uni finished, now was the time.
I opted for a neat GPS dock rather than trying to integrate the thing fully. That way, the GPS can be removed for other vehicles and updates. I’ll let the photos do the rest of the talking.
We have speakers in all the ground floor rooms of our house, all driven from the same amp. It’s neat but controlling the input requires going back to the amp.
Surrounded by iDevices too and with apps like iPlayer, Spotify and home share on iTunes, being able to throw audio to the speaker system had to be done. Que Airplay, however, this requires a nice Airplay amp or getting an AirPort. I then found out about Shairport, a program that emulates an AirPort’s Airplay function. With a Raspberry Pi kicking around, I had just found its new job.
Continue reading AirPi: DIY Airplay Speakers using Shairport and a Raspberry Pi
I finally got around to completing my musical colours project:
- Make the prototype permanent by building a perfboard arduino.
I wanted to keep the standard 5050 controller for general van lighting, controllable by the IR remote. I did this by using another transistor as a switch for the 12v line into the controller. One of the routines in the code then pushes the gate high to turn the controller on.
Having seen the Bar Fly I became set on a ‘SRM style’ mounting for my Garmin. I wasn’t set to pay £40 for one however.
Doing my research, it turned out the Bar Fly was inspired by a thread on a bike forum (a Triathlon forum none the less), where many had come up with a number of different mounting methods. I decided I could come up with my own variation using a £2 piece of acrylic from eBay and a dremel.
My first attempt is fairly crude compared to some fine examples of home design and build but it does the job for an hour’s work. If I can get my hands on a 3d printer I have some other designs in mind…