Scan failing. No connection at all

[Bumbolt]

I tested my crazyflie. It seemed to work well. Using the cfclient (on win7 host), using the xubuntu VM0.4 (with artoo lib and cfclient). No since this is a project at our college, i transported the flie in the case/box that came with it. When arrived on college campus the crazyflie wouldn't connect anymore. One of the motorcables came off. I solderd it back on but no difference.

What happens:

The flie boots normal:
Blue led on
Green led fast flashes and goes out
All motors spin once
Red led pulsing

When starting the cfclient and clicking connect. The dialog pops up, in the connect dialogue, i click scan. Whenever i click scan the red led on the crazyradio dongle blinks once. No other led activty happens (i don't recall the radio's behaviour before it stopped working)
In the dialogue it says "scanning" for about 1 second and then returns a blank list.
The console output (in the terminal, not the gui console) says "Serial with id N/A found". I looked up the source code and it's not implemented yet so this doesn't mean anything.

Connecting using a cold boot doesn't work (via bootloader). The connection times out.

I did flash the firmware with the lastest firmware available. But the connection worked after flashing it. I put it away for about 2 days before continueing (after transport) and it stopped working.

Any ideas?
My idea is, broken hardware possible at the crazyradio side (i have no spare to test with )

[Bumbolt]

The output of quickconnect:

Code: Select all

INFO:cflib.crazyflie:Callback->Connection initialized[radio://0/10/250K]
INFO:cflib.crazyflie:We are connected[radio://0/10/250K], request connection setup
WARNING:cflib.crazyflie:Got link error callback [Too many packets lost] in state [1]
INFO:cflib.crazyflie:Callback->Connected failed to [radio://0/10/250K]: Too many packets lost
WARNING:cflib.crazyflie:Got link error callback [RadioDriver: Could not send packet to copter] in state [0]

The code where the warning is generated:

Code: Select all

def linkErrorCallback(self, errmsg):
        print "Got linkErrorCallback"
        if (self.link != None):
            self.link.close()
        self.link = None
        if (self.state == State.INITIALIZED):
            self.connectionFailed.call(self.linkURI, errmsg)
        if (self.state == State.CONNECTED or self.state == State.SETUP_FINISHED):
            self.disconnected.call(self.linkURI)
            self.connectionLost.call(self.linkURI, errmsg)
        self.state = State.DISCONNECTED

Since state 1 = initialized. I'm guessing that the errors gets send out because the test packet doesn't receive an answer. This tells me there is something wrong with the crazyflie tranceiver rather then the dongle...

[tobias]

When you scan for it I guess you are getting nothing? Does the red LED on the radio dongle light up when you scan?

Can you visually inspect the radio components. The antenna is the chip on the edge marked AF and the small components is the matching filter. Look for an cracks in the soldering on any of those components.

Another thing to try is to disconnect the battery and only run it from USB and see if it makes any difference. Try also holding the Crazyflie really close to the dongle antenna.

[Bumbolt]

I have tested that radio components and inspected them with a magnifing glass. No cracks so far. I have also tried to hold my finger on each of them while connecting (inspired by a other topic here where soldering was lose). There are some rests of glue (of the battery sticker/tape) on the soldering of the square component closest to the antenna.

The red led on the dongle does light up as long as it says "scanning". No green blinking so no communiction there.

I did disconnect the battery and connect it to the pc with an USB cable. (I had to connect it with the battery, turn it on and then disconnect the battery for the leds to work). I has the exact same behaviour as explained. Same for the scan,quick connect and bootloader

EDIT: I also tried putting the flie close to the antenna to test for a broken antenna. I also took a laptop with wifi turned off to my yard to test it (interference). I also manual put a electrical wire (+- 5cm) to the antenna in an atempt to make it receive more. All without succes.

Isnt it weird that the flie does a succesfull self test if the hardware was broken?

EDIT2: I will try taking a high res photo from the components and zoom it to fake a microscope, making sure there are nog cracks.

I also realised that i transported it with the battery connected (very dumb). The white M3 cable came lose during transport. Since the glue was very soft when i tested at college. It could be that the M3 cable made a short somewhere, that would explain the heat to melt the glue. I tested the motor points they all mesure 2-3 ohm as they should and all spin correctly on startup. I only just now connected the dots.

What would be the most logical component to burn out on a short? Maybe i should start from there by mesuring al those components.
I'm no expert in electronics but since this is a school project i have access to some mesuring tools if needed.

[Bumbolt]

Seems like i found the problem. The square component is the nnRF24L01+ chip. The soldering or component must be damaged by the lose M3 cable (creating a short)

What is the best way to solve this? It looks that the soldering is to thin to fix it myself with a manual soldering iron.

How can i proceed best?


EDIT: better picture

[doddz]

If you think the Soldering might be broken on the nRF24L01+ then you could try the old oven trick. The idea is the high temp of the oven allows for the solder to fuse back together. Probably only consider this as a last resort as it would require taking all the plastics off as you don't want to distort them.

This would not make a difference if the problem was the component got shorted.

Sent from my HTC One using Tapatalk

[tobias]

Since the Crazyflie wont start when run from USB something is drawing too much current and is probably damaged. When the Crazyflie starts from USB the current is limited to 100mA and after a while it switches to 500mA which explains why you need the battery to boot it up. Does the nRF24L01+ get any hot? I would expect this being the damaged component but it can as well be something else. If you have access to a thermal camera you could probably find that component pretty quickly. The digital regulator will get hot though but might not be damaged.

Replacing the nRF24L01+ can be done with a hot air rework station and some experience. Maybe you know someone that could help you out?