Holybro 6c Mini for heli?

ArduCopter Traditional Helicopter
1

I’m looking for a new flight controller for my TRex 500 heli, and the Holybro 6c Mini is looking good, but I have a couple of questions:

The spec. sheet says maximum input voltage 6v, servo rail input 0 ~ 36v. So is the servo rail independent of the 6v input and not counted in the 1.5A current limit that’s quoted for ‘all other ports’? If that’s the case, if my servos run on 6v (as they do), do I feed both the 6v input and the servo rail in parallel from a single 6v 10A BEC?

2

The servo rail is isolated so yes, you would source it with a BEC for Servo Power. The FC power is typically provided by a power module, Holybro has a few different ones. These supply the standard 5.2V that these and other Flight Controllers like it use and sense battery voltage and current.

3

Thanks Dave.

4

I’ve got the 6c mini now and am starting to figure out how to install it. I’ve connected my receiver USB to it, and calibrated the sticks in MP after installing Ardupilot heli 4.7.0.

But what has puzzled at the moment is connecting a GPS: I would like to use a Matek SAM-M10Q GPS/compass that I already have, but will it be compatible? If so, will it be okay if I use it in the GPS2 socket instead of the GPS1 socket because I don’t have a plug that fits GPS1? Lastly, where can I find a diagram showing the GPS/compass/power connections for the GPS1 and GPS2 sockets? The sockets themselves have no indication on them other than the cable that fits GPS2 has one red wire and five black ones.

5

Yes, GPS2 will work. That’s what I used for my OMP M4 because GPS1 was a pain in the tail rotor to use.

6

Thanks Allistair, that’s good news. Google had found me that page but I never thought to double-click on fhe port names at the right :wink:

I have no real need for current and voltage data so can I forget about the power supply module and just feed 5v in direct from my Talon ESC’s BEC?

7

You will have to power the board with dedicated power module connected to PM port though, ESC BEC will only power the servo rail. It’s a great little board, I had my 600 fpv ship flown with that.

8

Ah yes, I remember, that’s basically what Dave told me at the beginning of this thread. Thank you both.

9

Today I connected my M10Q GPS/compass (which has previously been in service with a Matek board) to the GPS2 socket and the compass was recognised by MP but no satellites. Just in case the Tx and Rx were reversed I swapped those two pins in the connecting lead, but still no satellites. The M10Q is flashing green which I believe indicates a GPS lock – i.e. some satellites. Do I need to set anything in the config file to tell the 6c Mini to use the GPS2 port?

10

Just FYI, on H743 is not necessary to physically swap the pins: go into SERIAL#_OPTIONS , check “swap tx/rx” mask and reboot.

A quick way to check if GNSS is correctly wired/setup is through MP HUD view: on the bottom right corner if it reports “No GPS” it’s a wiring/ setup problem, otherwise if shows “no fix”.

If you post your most recent param set we can have a look.

11

I’d double-check wiring is correct (GPS RX to pin 2 of GPS2 Port, GPS TX to pin 3) and verify SERIAL4_PROTOCOL = 5, SERIAL4_BAUD = 115, and GPS_TYPE2 = 1 (or try 2 if that doesn’t work).

12

Thanks guys, I’ll try your suggestions tomorrow (it’s night time here at the moment).

(I swapped the pins because I remember back in history different boards had different meanings for the Rx and Tx connections.)

13

In addition to @nspector recommendation, set SERIAL3_PROTOCOL (GPS1port) = -1 if no GPS is connected to this input.

14

Thanks guys. I’ve made all the parameter changes you suggested and now my GPS is showing.

15

The Holybro 6C is a replacement in this heli for another Arducopter flight controller, so I started by loading my previous param file to it. I then went through all the usual Mandatory Hardware setups and calibrations before today going through the ‘Traditional Helicopter … Setup’ instructions step by step.

I’m now in a position where everything seems to me to be right but I can’t arm and the MP messages tab reports “GPS2: Was not found. Prearm: GPS2 still configuring this GPS.” Earlier on in the message it says “GPS1: detecting ublox.” then “GPS1: ublox saving config.” Attached is my param file in the hope that somebody can set me straight.

TRex 500 with Holybro Pixhawk 6C.param (18.3 KB)

16

I would set GPS1_TYPE = 0.

Since you’re using your second GPS port, I believe that forces your unit to become GPS2.

If I’m wrong and you still have an issue after that, set GPS1_TYPE = 1 and GPS2_TYPE = 0.

17

As far as I know if only one GPS is installed this is always set to logical GPS1 also if it is connected to the GPSport2. So you can try your GPS settings on GPS1 not on GPS2

18

Thanks again guys, GPS1_TYPE=1 and GPS2_TYPE=0 has done the job :smiley: All other paramaters are as suggested earlier in this post.