PX4 Coming soon to us all

The PX4 is here and soon it will have a fully supported version of ArduCopter:


From what I have been able to glean, Chris and Company are now in the process of revising this controller for better use by our group including an enclosure.

I Do not know for sure if they are planning on modifying the board itself but indications are that they are.

Now this is completely unsolicited by DIYDrones and may even be an annoyance to them, but there are some things I would like to see in there and I'll bet some of you would as well, so now is your chance to sound off before it becomes a fete acompli. 

Whether it will do any good or not I haven't got a clue.

An enclosure is good, but a internally vibration damped enclosure that was truly effective for reducing Accel vibrations to a fully tolerable level would be great.

Also, the existing PX4 pretty much requires that you use a PPM-Sum receiver with it.

PPM-Sum receivers are great, but only a few are available (Futaba and FR-Sky) not counting Graupner for obvious $$$$ reasons.

Personally I would like to use my plain old vanilla Hitec Aurora 9 and I think a lot of people would be a bit put off by having to upgrade their whole radio system because they didn't want to include a few extra RC inputs.

That's the 2 biggies I can think of, this is the place to put in your thoughts and we can see if anyone is listening.

This feedback is certainly unsolicited, I hope it is not also unwelcome.

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  • Thanks for explaining Gary, the blink pattern is the same, it was the red rather than green colour of the LED in the push button that confused me.

    I have also realised that failsafe wording in the HUD must refer to the failsafe settings on the RC tx/rx side rather than any of the arming or pre arming devices. 

    many thanks.

  • I'm sorry Martin for not being clearer.

    The arming externally mountable button that plugs in via 3 wires and a connector to the "start" socket on the PX4IO which came with my PX4FMU / PX4IO kit has a green LED in it's cap and it blinks continuously for a not "Pre-Armed" condition and 2 quick blinks and a pause for an armed condition.

    I presumed they all had green LEDs, but if the blink sequence is the same as mine, I expect it doesn't really matter.

    Basically after you plug in the battery, you have to hold down the pre-arm button for 5 seconds or so and your ESCs should initialize, usually with a musical sequence.

    Then you can use the normal throttle down and to the right move to actually fully arm your copter / plane.

    You can also over ride and disarm simply by holding the button down for 5 seconds or so again.

    You can toggle the pre arm button on and of by pressing it for 5 seconds or so.

    You can only arm with the throttle if  the pre arm button has already been pressed putting it into a pre armed condition (LED blinking twice then pausing before repeat.)

  • HI Gary,

    Can you explain a little more to me as I am confused about how to use the pre arming switch, what do you mean by the little pre arm button, are you referring to the LED in the push button arming switch, 'cause mine blinks red not green, or do you mean the LED's on the PX4 or IO board, also how does the conventional process of holding the TX throttle switch down and right interact with this.

    Also MP now shows the word "failsafe" on the HUD is this related to pre arm?

  • I actually have my F330 / PX4 flying very nicely in stabilize as of today.

    I had motors 3 and 4 reversed which resulted in a lovely takeoff back flip.

    I checked by holding the copter at low throttle and testing for it working against your tilting it and it worked in two directions but did the opposite in the other 2 immediately indicating 2 motor servo connections reversed.

    I have really good cheap GemFan carbon props and did it on grass anyway so no harm done.

    Possibly better to check first next time though.

    By the way the little pre arm button with the green LED that comes with the PX4 system is a real asset.

    I was doing some handheld motion testing as above when my undercharged transmitter gave out and it was running at medium throttle at the time.

    Pressing the pre-arm button for 3 seconds shut it down.

    It would have been a genuine problem if that hadn't been there.

    I really like the pre arm button as an extra safety step required before take off too.

    There is no mistaking it.

    If the green LED is blinking continuously and evenly it is not pre armed and cannot be armed with the throttle.

    If it is blinking twice with a longer pause between each pair it is pre-armed and can be armed with the throttle.

  • Hi Ravi, On the PX4IO board it is normally intended that the battery that provides the propulsion is normally also the battery that goes to the PX4IO battery input. It has a built in regulator to produce the required internal 5 volt and 3.3 volt supplies, that is why they also get their battery voltage reading from that input.

    On my Flamewheel, I just run the main battery line and the PX4IO battery input line, connected together.

    You will notice that the main battery leads and the PX4IO battery leads are simply paralleled in the drawings on my Wiki entry for this.

    Here: http://copter.ardupilot.com/wiki/px4fmu-plus-px4io-wiring/

    Normally with the PX4IO you do not need a separate (receiver) battery or BEC.

  • gary, this battery voltage being shown by PX4 is the one that powers the PX4 and not the propulsion battery. for propulsion battery voltage and current an external attopilot current and voltage sensor needs to be used which needs to go to a voltage divider pin (2 in this case).

  • Hi Ravi,

    Battery voltage sensing is built in as the Battery input to the PX4IO also provides the source for the Battery voltage sensing.

    Current is a different matter, I don't know if they have a defined pin for that yet.

  • next and last is current and voltage sensor. i guess i will figure it soon. it should have a ground and two analog voltage inputs.

  • hi agry, the airspeed sensor works fine. just connect to the connector marked "FMU PRES". just be carefull about the wires. the Vcc in this case is on pin 1 where as in the speed sensor it is on pin 2. works really great.

  • yes, you are right, i will try it today. it should work, because the Arduplane code is logically same for APM2.5 and PX4. the autopilot has to have a analog port for airspeed sensor.

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