Thomas Kolb's personal blog

Hi!

The hardware of my quad is now complete and assembled! Yay!

As pictures say more than a thousand words, here are some photos which show an overview of the whole construction and some details:

The motor controllers are all connected to the central power distribution board (PDB for short), which is also directly connected to the battery. The Lisa/M is mounted in the center of the PDB and rests on a piece of foam rubber, which is a very soft but still tight material. On the one side, the foam rubber prevents short circuits through the copper beneath, on the other side, it helps in mounting the board in level with the frame, as the bottom of Lisa/M is not flat.

The motor cables are held to the frame using Velcro strips. The RC receiver is also held by one of those strips, as you can see in the second photo. The battery is mounted on the bottom also using velcro strips (I hope they will be strong enough when in flight, but as I can lift the quad only holding the battery, I don’t think this will be a problem). Finally, I have added a piece of heat insulation tube (which is light, but quite stable) on each arm of the quad to keep the battery from touching the ground and to act as a damper in case of hard landings .

By the way: the transmitter problem is also solved. There seems to be some problem when building the paparazzi software inside of a 32-bit chroot environment on 64-bit systems. The DX6i transmitter works without any problems when building the software on a real 32-bit system or inside a virtual machine. So, if you want to use paparazzi, too, I recommend to use a real 32-bit system or a VM.

To summarize: The hardware seems to work completely now. I still have some software/configuration problems, which will hopefully be solved soon with some help from the paparazzi team . So I think it’s not long until the first flight!

Hi again!

Yesterday I basically built an aluminum frame for my quadrocopter in a six-hour marathon. Before I go into detail, I’ve got some pictures for you:

As you can see, the frame mainly consists of square aluminum pipe, which you can buy at any hardware store. The dimensions of the pipe I used are 15.5x15.5x1000mm with a thickness of 1.5mm.

To get the two rods on the same level, I cut halfway through each one so I could put them together to a “plus” form. The whole construction is held together by four screws with 6 mm in diameter and two solid plates, consisting of wood on the top and plexiglass on the bottom (maybe I'll put some LEDs there some day ).

The topmost plate you see is the “Power Distribution Board”, which will connect all the motor controllers to the battery in the end (I hope the 5mm tracks are enough for 50A peak current ) and also hold the Lisa/M.

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So, that’s the new frame, and here comes the status update for the rest of the thing:

First the bad news: I returned my Spektrum DX6i to manufacture because the first channel wasn’t received correctly by the Hobbyking Orange receivers. I also tested with another DX6i, which worked, so I assumed there must be something wrong with my transmitter. Today I was told by the Spektrum support that my receiver works perfectly normal, but I got the DSMX version which obviously has some compatibility problems with my “unofficial” setup. Maybe it’s possible to implement some workaround in the Paparazzi software, or I have to get myself the DSM2-only version of the DX6i.

At least there’s some progress: propellers are ordered and should arrive this week!

So in general, I guess it doesn’t look too bad for my goal of flying this thing at the Chaos Communication Camp (maybe with someone else’s transmitter...).

In the last few days I prepared the motors and controllers. That means I have attached all the connectors to the wires of motors and controllers so they can be easily plugged together.

Finally I built a little test setup with all four motors attached to a piece of cardboard. I also attached a piece of paper to each motor to get a bit of air resistance (but I don’t think it resembles the load of real propellers very well ). To be able to set the motor speed, I wrote a little program for my AVR evaluation board which generates the signal for the motor controllers, which was distributed equally to all controllers.

Here are some images of the setup:

I took these photos at relatively low speed (about 20% according to the signal on the oscilloscope). At full speed, the whole setup draws a current of about 4A, so 1A per motor, which is not that much, as the motors are specified for up to 12A permanent current (15A peak). I guess the current will be much higher with real propellers.

Anyway, I wouldn’t be able to test with much higher load, as my power supply does only provide up to 5A .

The next step will be a test of the Lisa/M with the motors and the receiver connected, so I will finally see if all the hardware works together.

This time I’d like to tell you about my plans of building a quadrocopter.

I already have most of the components, so I guess I will start to assemble them soon. For the record, this is what I already have:

• Battery: ZIPPY Flightmax 2200mAh 3S1P 25C
• Motors: Turnigy 2209 28turn 1050kv 15A Outrunner
• Motor Controllers: Hobbyking SS Series 25-30A ESC
• R/C Receiver: OrangeRx Satellite Receiver
• Autopilot / Control board: Lisa/M from the Paparazzi Project

Propellers, a frame and (most critical) crimped PicoBlade wires for the Lisa/M are still missing – the wires are already ordered and should arrive next week. I’m also awaiting a frame from HobbyKing, but that was somehow lost on the way to Germany and they have started investigation about it. But, even if they re-sent it tomorrow, it would still take about a month until they arrive, so I will probably build my own frame for the start .

Anyway, I still hope to get the whole thing airborne before the Chaos Communication Camp in August!

Hi there!

Recently I decided to start a blog instead of updating my old (and totally outdated) website. The old page will stay online, of course, but I will probably not update it any more. The reason why I started a blog is that I don’t have enough spare time to maintain the code of the old site (which I mostly wrote while I was in school, so it is really chaotic ).

Some updates for those who only know me through my old page and wonder why there where no real updates for my programs in the last two years:

• I have fully converted to Linux!
• I am currently studying Electrical Engineering at the University of Applied Sciences in Ingolstadt. Thus, my interests were shifted a little towards hardware in the last 2 years.

By the way: I am writing all this in English because I think I will have some readers who don’t understand German, but are still interested in my projects. I’m still thinking about a good name for this blog, so don’t be surprised if it changes some times during the next weeks.