Build blog
From Quadcopter
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June 2008
26 June 2008
The first electronic components arrived today at stews office, all the way from Hong Kong... Take a look... next parts should be here soon...
22 June 2008
No don't worry we have not given up on the project.... We have just been doing loads of research into all the electronic components that we will be using and placing orders for them from the US..
Take a look at the Parts List it will show you all the parts we have decided on so far and what we have ordered.
Will be adding some tech notes to the website soon as well and will post a few pics as soon as the mail man arrives with the first components.
15 June 2008
Electronics setup and motor controller
So on Sunday morning we got working on the first electronic parts of the quadcopter. The plan for the day was to get the motor control operational from the microprocessor with an input coming for a serial port.
We started off by getting the oscilloscope up and running so that we could check the signal we were generating, this came in very handy as we would soon see.
We then started off building the prototype board with the atmel mega 8 as the main control chip for generating the PWM signal.... we hit 2 problems that we never thought we would have ever done.
First time we hock the board up with everything connected, we connected the wrong power source wire's, so we were pumping 12v into the board instead of 5v... with a quick rip out of the wire's after seeing this on the multimeter we were hoping that we did not blow the ISP programmer, but we would only know this once we got it all up and running.
After changing the wire's to the power supply and making sure we had the right voltage we thought it was time to try again. so we plugged it all in again and crossed fingers, after such a stupid mistake surly we would not do something like that again... NOTHING.... Stew trys thinks we might have blown the atmel chip with the 12v we were feeding it. He touched the chip... "aaaaaaaahhhhhhh" screams Stew, "The chip is F****ing hot" so we turn it all off again and check the wiring. Turns out we had connected the 5v power into the analogue to digital converter pin instead of the vcc pin.
We changed the wiring and checked it 100% as we did not want to make a stupid mistake again. NOTHING..... but this was not a surprise as we were almost sure by this stage we had blown the atmel, so with a quick swap out of the chip finally everything was running 100%
We weird up an LED to the board and wrote some code to make it blink. Yay it was working now we could get to work on the code to generate the PWM signal to control the Motor.
We had some problems at first with generating the signal as we were still getting our heads around the atmels data sheet. Finally we figured out the right equations to use to get the numbers for the right pulse width. we thought it would be best to get a servo moving first as this uses the same signal as the motor controller. Now with the right signal being generated it was not hard to get the servo moving and we had that done in no time.
Time to move to the motor controller... we first got this running as normal and just made the motor speed up and slow down but itself. we then programmed in a serial controller so that we could start getting so debug info out the system. this turned out to be way way easier than we thought, and in a short time we were getting info out of what our program was doing. we moved on to start making the speed of the motor controllable from the serial console, with a few tweaks of the code we got this done.
You can find the code here or from the downloads section under tests.
11 June 2008
Well we bought a few right angle clamps to keep the frame square, but after attaching the first one to the frame and then checking the other side with a tri square we bought.... things were not aligning. It turns out the expensive tri square we bought is not quite square....
We then cut the the 4 strengthening bars, drilled the holes for them and attached them to the frame.
We were going to rivet the bars to the frame but thought it would be best to bolt them on as we might want to use the same bolts for the landing gear or camera mount at a later stage.
Well now with the frame pretty much done and only weighing 296g things are looking good in the weight department. We hoping for a weight of not too much more that 1kg as we would like to hover at about half throttle. We have done some testing and it seems with the 4 motors we should get about 2.4kgs of thrust.
Mock up with right angle clamps.
Mock up of strengthening bars.
Mock up with holes drilled.
Final outcome after it had all been bolted together.
Just a pic to for us to keep track of weights...
Well now that most of the frame is done, we need to start working on some of the electronics. First thing we will be doing is getting the electronic speed controllers that power the 3 phaze motors, to run off our microcomputer (Atmel Mega8's) we will be generating a PWM signal that will tell the speed controller at what speed to run the motor at...
9 June 2008
Here are a few pics from the first build night... we had a few planning nights before this but this is the first "Build night"
Filing down edges after first frame cut.
Measurements with our new R200 steel rule for the first notch cut.
The plan is to make the frame as light as possible, so we used aluminum for the bace of our frame.
The new work bench in a now very clean garage. The door we using as the table top is a bit narrow so as soon as we can get a new door we will replace it.
Filing down the noches in the 2 main struts to make them fit just right.
Well this is as far as we got the first night, reason being, as i was cutting the next bit i bumped our work light and blew the bulb so we had to call it quits for the night as we could not see a thing.
