It's been a while again

Well it's been quite some time since I last updated my website, and quite a few things have happened since then. Firstly, I've finished the semester for the year, it was due to be my last semester providing I passed all 4 subjects, however this was not the case. But the situation isn’t too bad, providing I can manage to complete 12 weeks work experience before a certain date, I can apply for an additional exam for the subject to allow me to finish up the course this year. The thing for the moment is just finding out a position, but the free time has enabled me to work on projects and generally start working on parts I’ve wanted to get working for some time.

The main thing I’ve gotten working is a 3.2” TFT LCD screen with resistive touch screen and SD card socket I got off eBay. The SD Card socket has helped when I made a few touches to the Maple SDFat library and will be used more in the future to load images onto the screen of the LCD. A week or so ago, I got the touch screen controller working for the LCD and soon after I managed to get the actual display working as well.

At the suggestion of zyp from #leafblowers on freenode IRC, I did a Mandelbrot set calculation on the Maple which works reasonably well although takes some time to make the calculations, it does work. Using fixed point for the calculations or using a microcontroller with a floating point unit (FPU) would cut down the time to ‘render’. The last task I need to do is port the Adafruit TFT library to the maple platform with the changes needed for the different controller the screen uses.

In the future, I plan to use the display to create a touch screen alarm clock with integrated weather station.

I’ve also made progress with Project SEPA! After doing another test piece of the fibreglass with resin, I decided to finally cut the pieces out of the plane fuselage and reinforce where I cut with the fibreglass. I also removed the old servos and will be putting in the new servos soon. In a slight change, I cut a small amount of foam from the wings to allow another servo to be placed into the wing to allow more control over each individual aileron meaning I can use them as flaps or elevators. I will be making a post in the near future about the work being done and the changes to the plane.

I also have been working since October on a Raspberry Pi powered robot! I called it the Raspbian Rover (partially inspired by the Curiousity Rover) and it has a Maple Mini connected via SPI to the Raspberry Pi. I will be writing more about it in the future and how it came about; I have actually recorded a video of the presentation I have done at the Melbourne Raspberry Pi Jam (twice in fact, I did it again at the Mid Month Software Jam they hold at RMIT Melbourne) and at Melb PC Hardware SIG. Apart from being a nervous presenter, all presentations went well and seemed to be enjoyed by the audience; although making the video I found was harder than doing it in front of an audience! The video still needs to be edited, but should be up in a week or so.

Another RPi related project that I did involved making a webcam mount out of wood and with the help of 2 cheap hobbyking servos, made it look around from the top of my desk. The purpose of this rig was to allow me to check up on the cat when I was in Sydney similar to how I did it last time I went upto Sydney. I’d remote into the server at home and turn on my gaming computer so I could use the webcam attached to it. This system of course had a few draw backs, mainly powering up a power hungry computer (300W idle) isn’t the best of things for the electricity bill, but also the printer was connected to a energy saving powerboard meaning it was turning on as well, which also meant the location where the webcam was pointed was useless as the cat would run to watch the printer! After that trip, we were determined to make a better system to allow us to have something lower powered and also could look around our place. I’ll write a little tutorial on it later, but essentially I used a little switch mode power supply to power the servos and the Arduino (used only to control the servos, initially had problems with it, but discovered it was just a power problem) and connected the webcam and Arduino to the RPi. I intended to have either a cron script or something to take pictures every so often, but ran out of time and just remotely connected to the RPi whenever I wanted to a take a photo.

I also got some new hardware, I made a copy of the Saleae Logic (very poor copy) for around $16 or so (the main cost was getting a Cypress EZ-USB development board). I’ll write about that project in a post for later, but will say that I’d highly recommend a real Saleae Logic. I actually managed to get one when a friend who graduated from my university approached me and asked me if I wanted one for AUD$100, so I decided to go for it. It’s become a very valuable tool in finding out what’s going on in my projects as I can probe 8 channels. The most recent time I used it was debugging why the SPI Port expander I was using to drive the LCD lines wasn’t responding, the answer was slow to find until I used the logic analyzer and worked out that a bit was in the wrong place for the start packet, something I overlooked when reusing some code I had used for the I2C variant of the same chip family.

I hope to continue the work I’ve been doing on these projects as well as start documenting the projects I’ve been doing more thoroughly on both my website as well as doing videos on youtube.

Lastly, I will be running a Raspberry Pi Jam on the 2nd of Feb as well as running a workshop on connecting electronics to the Raspberry Pi. So expect to hear about that in the future and I’ll let you all know how it went.