X4 first maiden


2years ago I worked at a job that needed me to configure different quadcopters on different autopilots. I have done ap and micropilot etc.  After quitting the job for various reasons I bought a 3Drobotics quad kit with ardupilot. 

Now since I have many projects that actually need to be dropped from heights (starting from sensors and ending in skydivers practice tools) I decided to upgrade my aerial system to this: The gopro is just for size comparison

PX4 works like a charm. The first time I fastened the props I had a perfect flight. This was not like the arducopter. I got all the logs I needed to evaluate the system in one go, there is magical and fast connection to usb and all those little things. 

Just calibrated it, configured the board and compass orientation and threr PID-s a little lower (since it has 330KV motors).

I am flying with 6C and 20Ah batteries so that meant I had to mod the 3D robotics regulator for this (pulled the original regulator module out and added my own 30V reg). Also switched the voltage divider resistor to something that fits my configuration better. 

This thing just flew without any pre-tuning on ropes or at hand (thou to be honest, getting props to spin up while not 3m away from the device is not an option with something like this). 

Soon I will go for autonomous system configuration, but today is not that day, and I have done that so many times that I do not expect to see anything new happening there. 

Also, just for the record the current test configuration gave me worst case flight time of 32 min and best case of 40 minutes. This is without any payload and with little calculation magic to get the numbers. I just could not wait to get to the logs so real time was around 10 minutes.  

Also for those who wonder, the frame design is custom and not the cheapest one. but yes Pixhawk is awesome. 

Do Recommend. 

Some extra pictures: 

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  • John, I ripped the module off board and only use bat inp, gnd and output voltage. The regulator is 3A capable based on generic switching IC. I have pots on that for voltage adjustment and some super glue to keep the pots in place. Output is +/- 0.08V over 10 degrees to 25 degrees Celsius. 

    The module datasheet you showed should give no errors. what output you got and what were you expecting? also what was the load you measured the output at ? 

  • Very nice Markus! I am very interested in how you converted the 3DR power module to 6C. I tried to do this very thing a few weeks ago, by replacing the DC/DC step down regulator with a murata OKI 78SR-5 like the one here

    but had trouble with the voltage out not being correct. Can I ask what specifically you did on your mod, and how accurate you judge the measurement of voltage and amperage from the module? Thank you!

  • to answer the kolin question, the pixhawk and ardupilot are 1000 times better than micropilot. (not only on quads but to my experience on planes as well) And DO NOT ever underestimate the power of ublox module that 3DR has created. Micropilot does not even get close to it thou they also use ublox. It costs around 5000 - 8000 dollars and is inferior to ardupilot in any version. 

    Others do get close or even better ( easier to get to fly ) but on the bang per buck scale Pixhawk is way better.

    Only real compeditor to pixhawk is naza. At least to my knowledge at the moment. 

    For now I have no useful info on the reliability of the pixhawk, but I have configured many systems and not one has failed because AP2.5 (no info on Pixhawk yet). Also water damage does not count as failure of autopilot, but mechanical failure.  

    Milan, I am using 2x 10Ah batteries there. It is pretty heavy, but flies like a bird :) 

    Tom, sadly I can not give you answer at this moment, since I lost the slip for the props. I will find it and try to update. But today is mid summers eve and i would not like to start going trough papers to find it :) 

  • What size props are you using? You didn't mention it.

  • Gret design! Could you please tell us about other autopilots you worked with, like micropilot? It is very expensive and I wonder if well tuned pixhawk can do the same.

  • 20Ah batteries=how many units?

    Great work, pixhawk seems to be a great success!

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