How to verify GPS lock?

I’m using a Matek H743MINI board in a TRex 500 running the current Aruducopter, and have finished testing it bare frame. It’s now about to go back into its scale fuselage, where the GPS module is going to be out of sight so that I won’t be able to see when it gets a GPS lock.

Is there any way I can program the buzzer to indicate that GPS lock has been achieved, or that it has a specified number of satellites, other than trying to arm the craft and then getting the ‘Failed to arm’ buzzer sound?

Or alternatively, is there a simple way to interrogate the Matek board or the GPS module to get an output that could be used to trigger an LED that I can mount inside the heli’s cockpit where I can see it?

Activate the fence. And arm the copter until it accepts it.

You can also buy the USB port and LED that are on an extension and place it in a convenient place on your aircraft. The LED gives you a status of the flight controller. When it turns green then it has GPS and is ready to fly.

Well green light doesn’t help because after taking off and switching to loiter there will be red light again until it gets certain amount of sats green light barely helps but if its blinking fast then we can trust for good gps lock but it happens very randomly

Thank you for the suggestions.

amilcarlucas, my understanding of ‘Fence’ is that it enforces physical boundaries to where the copter can fly. Are you saying that with a Fence defined, when I give the ‘Arm’ command it won’t actually commence the arming process until a good GPS lock is achieved? If so, the danger as I see it, is that the copter might arm itself while I’m busy chatting to someone while waiting for the sats. :frowning_face:

bnsgeyer, that sounds good. I’ve already got a USB extension routed to the front of the heli, but the only LED extensions I see when I search the internet use two ports on a Pixhawk board, like this one. Is there the same kind of thing that simply plugs into the USB port?

Goobisofty, I’m not worried about what the LED does once the copter is in the air. I just want it to go green when my GPS gets a good lock.

Yes fence will prevent arming without proper GPS lock.

No fence will not automatically arm the copter behind your back. You are still required to manually arm the copter.

OK, that’s the situation I’ve got at the moment with regular pre-arm checks. But no visual indication when it’s in the scale fuselage, so I just have to keep trying until it arms.

What transmitter and receiver have you got? is it possible to set up telemetry and the yaapu script?
You’ll never go back after having the telemetry onscreen on the transmitter!

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Whats the point of having meaningless led which only changes status and show about gps locked once its armed and in the air i dont get it it should only blink green on ground when gps have minimum number of satellites which can be configured by the user lets say 12-14 sats

xfacta, I’m using a FrSky Taranis X9D+2019 Tx and FrSky X-series Rx which gives me real-time telemetry, and is communicating with the Matek board by SBUS. At the moment it’s only set up for motor and ESC temperatures (they get hot inside the scale fuselage), but how do I capture the GPS status from the Matek board to send to my screen? If I can get the GPS info to my Tx then I can have visual and/or sound alerts of the GPS status.

You’re missing my point Goobisofty; I switch on the Tx, then power up the heli, then wait for GPS lock as indicated by the green light on the GPS module, then arm the heli and fly. I know that if it hasn’t got GPS lock Arducopter will give me the ‘uh-ohh’ sound and won’t arm, but I’d rather be patient and wait for the green light before trying to arm. When the heli is in its scale fuselage I won’t be able to see the GPS or Matek lights, so I was hoping to be able to have one in a visible position – if there’s a simple way to do it.

Xfacta is right, once you use Yaapu telemetry there’s no going back.

You should be able to run it with that gear. It will mean running one extra wire. I haven’t used your exact setup so I can’t say what port to use but I’m sure somebody here will be able to steer you right.

Thanks for the link Allister. I’ll follow it up.

Yeah, it’s great. You’ll be able to see all the messages plus HUD with all the relevant data.
After you’ve got it working you’ll be wanting to set it up on your bicycle, kettle, car, strap a flight controller to the kids…

Maybe the only trick will be still getting those motor and ESC temperatures

Once Yaapu is up and running, and if you have FENCE_ENABLE,1 , you’ll here spoken messages somewhat similar to “GPS 3D fix” and after a short while “Home position acquired” and you good to go.

Thanks xfacta. I’ve had a look at Allister’s link, and the Ardupilot wiki about the FrSky interface, and it’s looking a bit daunting at the moment. First thing I’ve got to figure out is where on the Matek board I get the signal from.