I have assembled a new APM from the diydrones store and uploaded the newest code for Jan.3 (1.01).
When I have the APM/IMU installed in my Easystar, the PPM light flashes and the A B C light never go into a flashing state for calibrating the gyros. All of the airplanes control surfaces and throttle work normal but the ailerons have a twitch that matches the pulse of the PPM light.
On the benchtop, I have a BEC powering the APM with 3 servos connected. Upon powereing up, the ABC lights flicker as normal and the aileron servos no longer twitch. When I try to use my transmitter to control the servos, they work normal but after a few seconds of inputs the APM resets into calibration mode.
I've tested the flight sim and everything works on that end. My older APM works with the newest code from Jan 3rd just fine on the Easystar.
I think the issue may be bad firmware for the PPM Atmega328 chip but I wanted to run this past ever one before ordering an AVR programmer.
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I've scoured this thread hoping to answer a problem of my own.
I think I may have found a fault in the PCB layout of the ArduPilotMega?. This is a little difficult to explain but I'll try.
I have a v1.4 PCB with attached oilpan & DIYDrones GPS & magnetometer. I have a newly built quad which I was in the final stages of setting up. I have a Turnigy 9x Rx, eight channels are connected to APM. I also have four unbranded ESCs connected. The only other connection is 0 & 5v from one ESC to two pins of the APM I/O connector.
While testing the setup everything seemed to work much as I would expect then suddenly it died completely. The APM would work fine if USB powered but not if powered through the I/O connector. On close inspection of the APM I noticed that the 0v track on the underside of the board running between IN5 & IN6 had burned out.
Mystified, I did some probing, there are plenty other 'ground' tracks on the I/O connector BUT as far as I can tell these don't connect to ground!
Just to make sure, I scraped off a patch of resist on the 'ground plane' which connects these tracks, it is NOT connected to ground on my board now that the above mentioned trace is broken.
If I'm reading this right, the only power connection to the APM (and oilpan etc) is effectively the 0.25mm track between IN5 & IN6.
This is quite difficult to check. As long as this track is intact there is continuity between all 'grounds' but when it's broken none of the 0v pins on the I/O connector are grounded.
Unfortunately I can't check the layout in Eagle as I only have a Free version which (apparently) can only display two conducting layers so I can't see the ground plane.
Anyone having problems powering their APM via the I/O connector might check that the 0v pins are actually connected to 0v.
Maybe someone familiar with the PCB layout can explain where the I/O connector is connected to ground?
I do have a couple of problems with my reasoning but I think I've waffled enough for now!
I'm getting similar results. I've got a 1.4 board. Everything works great when the USB is connected. However, if I try to power it via the ESC only, it never boots (no ABC LED activity). I get power LED, servo twitching, blue LED activity.
I've pulled down latest code and replaced the entire Arduino directory (libraries included). No joy.
I checked resistance between SJ1 and my UBlox "+" terminal (with power off): 90 ohms. Solder blob isn't shiny but it looks good otherwise. I checked the output of my airtronics receiver when using a 12vdc benchtop supply and it's about 4.8vdc.
The only diff between my bench and field setups are the usb cable, and batteries instead of benchtop power.
Everything works great (manual, stabilize, HIL testing) when USB is plugged in. CLI adc test result:
ADC
1694 1629 1621 1424 2062 1990 2459 2853 0
1693 1629 1621 1424 2062 1990 2458 2851 0
1693 1630 1621 1424 2062 1990 2459 2850 0
1693 1629 1621 1424 2063 1990 2458 2849 0
Not sure what each column represents, or why the last one is 0.
Is there more tests I can do to isolate this?
Here's a pic of my setup:
I
had a similar problem two days ago. Erratic behavior of APM- resets during IMU initialize, flickering of the yellow Ardupilot board LED, noisy servos when idling etc. The problem did not occur on the bench when BEC and USB cable were connected. Checking the APM supply voltage with a scope uncovered the suspect. See attached foto. (2Volts/Div). Obviously my BEC was could not deliver sufficient amps. I put a 5V voltage regulator (7805) in parallel to the BEC. Not quite state of the art but solved the problem.
Model: modified Easy Glider
2 Lipo Cells, 30Amp brushless controller with BEC, Spekktrum 8000 receiver with telemetrie module, 5 servos.
I just wanted to report that I am experiencing the exact same reaction from my APM as shown in Peter's video. A friend of mine ordered a v1.4 on the same day as me and is experiencing this as well.
I have similar reset problems.
When I go to Stabilize mode after the first completed calibration process, if I roll/pitch the aircraft, the APM resets to the calibration process. It may continue to reset when calibration has completed.
My system is: APM v1.4 and IMU -h with 4 servos. The APM is powered with a 3 cell, 3000 mAh LiPo battery through a Castle Creations 10Amp BEC, The BEC 5 volts is connected at the APM servo rail.
The problem occurs when the XBee is connected at the IMU board per http://code.google.com/p/ardupilot-mega/wiki/Wireless. If I remove the XBee the system does not reset in Stabilize mode.
Note: I do not always get the elevator kick during the calibration process.
I measured the voltage at the servo rail of the APM board at 5.0 volts under all conditions.
I measured the voltage at the +5 pin for the Airspeed sensor and the XBee +5 pin. It measured 4.57 1st startup but went down to 4.48 to 4.45 during the Stabilize mode just before the reset. There is a 20+ millivolt of square wave at XBee rate in Stabilize mode just before the reset.
I found that the +5 pins for the Airspeed and XBee ports are NOT directly connected to the servo +5 rail.
With ohm meter leads connected one way I measured infinite resistance (with Cap charge indication) and about 120 ohms measured with the ohmmeter leads reversed.
If I power the XBee from the servo rail +5 volts I get NO resets.
Note to the developers: You guys are doing one hell of a great job on these projects. Thanks.
Yup Ch5 is on a 3 pos toggle - connected to in8 on the APM.
Bit worried about the lack of regulators in spectrum systems - do futabas have them?
My open circuit voltage on the battery is about 5.1V and when connected to the APM the voltage across the rails is 5.01
I hope that my APM is not damaged.
I doubt that's the PPM encoder, since it's coming straight from the DIY Drones factory.
Please note that the pin numbering has changed (it's now 1-8 rather than 0-7). Are you sure your connectors are going to the right pins?