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Showing posts from September, 2013

New Chapter: Barebone Arduino

With this new Autopilot Concept Change I decided to move on from Shields build my own Barebone arduino. A bold move but necessary for the future of this project. The major problems with is their size. Now it you don't have a problem with size and weight and Shields is for you. But the most annoying thing about them is the fact that honing on your electronic and soldering skills is no longer expected which I feel is the biggest short change any inventor can do. Hence came the Atmel328 microprocessor. That's right! Every Arduino Uno processing is done by one. So you might just as well get to know it. There's plenty of others but the simple interface of the Arduino IDE, makes this a breeze to program. I need to upload the bootloader (quite easy). A quick trick to change programmer to "Arduino as ISP" and change the board type. It's a no brainer: one Arduino Uno costs R300. Total cost of putting a working Barebone is less than

Autopilot Concept Change

After a bad case of stomach bug, I stayed at home today and got working on he UAV both hardware and software. The goal was simple yet daunting: Transfer 3 shields worth of hardware to one protoshield. Due to the high turnaround of making a custom-made PCB (which I have a fair experience on). I decided to go the perfboard route and make the conceptual design straight on the board. It became quite obvious that a few things could be done to reduce the size of the hardware: Instead of having the 5V regulator (although it will be added as a bakcup option) power supply could be taken straight from the ESC. I measured a voltage of 5.05V The need of transistors on each servo channel can be replaced with the switching done in the controller. This can be managed more efficiently. The sensors are attached on the board using right-angled header pins allowing the sensor boards to stacked upright leaving space for more sensors such as a barometer, and the prize sensor: the GPS. Having mad

OpenLog Testing

So I managed to wire the OpenLog sensor and ran some few read/write code to make sure the wiring works as expected. And it works!!! This device will enable me to log any data that will be used for the flight controller design. This is prior to mounting a GPS sensor for waypoint tracking. The SoftwareSerial library has been used instead of the serial pins 0 and 1 so that only selective streams will be logged while leaving the option for bebug logging. On the custom board, I'll have to accommodate for quick removal of the OpenLog board in the event Logging us required somewhere else.

My new logger finally arrived: OpenLog

My new logger sensor finally arrived!!! Since my MicroSD shield died on me, I realised that I needed to serial logger to be able to collect data for flight controller design. I also realised that getting the OpenLog board will expand the capability of the autopilot. The best thing about this board is its size. Being only a few grams and just over 1cm across each side one thing left to do: wire it up! I'm in the process to finishing the 'LOGGING_MODE' of the 'autopilot'. This should be able to still maintain control of the glider and capture of the necessary inputs to begin flight controller design. I'll keep you posted!

New Portable Device: DIY Hot Foam Cutter/Shaper

So After making my hot wire cutter , I realised that I still needed a portable devices to make grooves, channels and enclosures in the fuselage body. So came a brilliant idea. Replace the tip of a soldering iron with a solid 2mm diameter copper wire. The wire is ductile so it can be shaped in any form desired. I found out though that the length of wire is important as that determines cutting temperature. Too long and the wire is too cold to melt foam. Too short and the wire "over-melt" the foam instead. With this device, foam has become the next best thing when it comes to airplane design and build. The complexity of the design is only left up to the imagination of the designer! Below are some examples of what this awesome tool can do.

Pre-flight Testing - Weight and Balance

So I've finally arrived at a time all aircraft engineers hope to get... Maiden flight. But I've had too many experiences where the maiden flight is all but over in a matter of seconds becauseI was too eager to "free the bird". The end result... A disgruntled soul wishing it had been more patient. I've learnt my lesson (with my wife's mentoring) to be more methodical and pragmatic about my approach to the maiden flight. Since I don't have the luxury of wind tunnel testing of the wing and the airframe, the only reliable weapon in my arsenal was... Calculations. To be more specific, weight and balance calculations and measurements. After using AutoCAD, a weight balance spreadsheet to calculate the estimated (emphasis on "estimated") center of gravity in relation to the wing mac (mean aerodynamic chord), measuring the actual cg will all electronics included was the next (and hopefully) final step. It must be said that prior to this step I reali