Mobius Camera Install

Used most of the supplied mount to mount Mobius (Lens-A) camera. Drilled a 1/4inch hole in the middle of lower plate and used a (cut to exact length) 1/4in. nylon bolt to attach it. A little foam tape at front and back (just to make sure it doesn't turn and/or loosen). Between upper plate and body, I used two small nylon washers to help even-out upper plate due to rubber dampening ball's grommets in corners.

The wire-ties and fishing line are for emergency tethers (and are required ... balls won't hold in crash). One loop through all plates and parts. Even in this default position, landing gear does not appear to be in Mobius wide-angle lens.

Willing to give-up tilt to have camera up higher. Might adapt or hack a Mobius mount later. Obviously, no gimbal yet, but not really any "jello" either so stock mount is fine for now.

Current Settings (updated 2015-03): I just set my Mobius exposure to "Sunny" instead of "Auto". Just one flight that way but seems much better (especially when facing the sun). Instead of the camera temporarily making the rest of the scene dark, and then slowly transitioning back, it's more of a constant brightness. The sun just looks bright and there are some cool halos now. Anyway, thought this tip should go here.

Update 2015-06 Changed Primary recording mode to 1080p/30fps Narrow. Will decrease "fish-eye effect" when camera is pointed down. While the end-effect looks like a zoom, it's actually a pixel-matched 1080p recording from middle of lens. I also tried 720p/60fps/Narrow ... while it is smoother, it's not as sharp when played back on 1080p monitor. I have it setup as Secondary.

Telemetry Upgrade Mod

The parts arrived last week, so I did the Telemetry upgrade on my Quanum Nova. Yes, connector is missing, but you can see that PCB is ready for it. This post has been recently updated, so read the whole thing before attempting.

Supplies:
HobbyKing Telemetry Radio set v2 (915 Mhz) ... aka SiK or 3DR Telemetry Radios
Molex PicoBlade 5-pin connector (53047 Series)

Phase 1:
Removed lower connector board from FlightController.

 

Soldered in PicoBlade connector (watch orientation). You want red wire on cable to connect VCC power to 5v on radio. Solder with plenty of light and a magnifying-glass helps (the solder-pads at 1.25mm spacing are very close).

 

 

After soldering, I checked for unintentional shorts and proper continuity with an ohm meter. All checks out good. 

Installed the 4-wire 6-inch cable (supplied with radios).

Re-assembled enough for testing and to prevent any chance of short-circuits/damage.

Phase 2:
Connect one radio to Nova via PicoBlade cable, and the other radio to computer via  supplied Micro-USB cable.
Connect LiPo battery on Nova.
Start MissionPlanner. Set to "Auto" and then click connect.
Connects and works fine. See Artificial Horizon and Compass Heading respond on computer.

 

 

Phase 3: Mounted here with foam tape for now. The slot cut for wire access is in "channel" next to battery area (as to not affect body strength). According the RSSI bench-tests, having this 915mhz radio on doesn't really affect FrSky 2.4ghz radio (even though the 915 antenna and 2.4ghz antennas are fairly close in this location).

I have since moved Telemetry radio inside Nova.

Notes:
It's come to my attention (from RCGroups posts) that this mod might only work if the FC is still running the stock-factory Arducopter (in my case v3.1.2). I put too much work into this, so I'm staying on ArduCopter v3.1.2 for now.

This version of the HobbyKing Quanum Nova Flight Controller are marked like ... PCB-1: APM_V252_V2.0 and PCB-2:  CON_V2.0 . In Jan-2015, some newer revision board are showing up and it sounds as if the boards are different and connector pre-soldered-in (but accidentally backwards, according the established 3DR pinouts). If using pre-made cables, check your VCC power with meter first.

The direct USB connection and Telemetry radios CAN NOT be used concurrently. Pick one or the other each time. If using Telemetry radios, do not connect normal direct-connect USB cable to bottom of Nova.

My radios came pre-programmed with matching settings (required for basic link and normal operation). There is an utility in MissionPlanner that can be used to verify and/or change them if needed, but I didn't need to use it in my case. IIRC, it is like in the Settings section and radio module on Nova just needs to be getting power also.

While the Telemetry port is 5-pin places, there are only 4 wires and/or connections. Two are for power (VCC+5 & GND) and should never be swapped (verify with volt-meter). The other 2 are signal RX & TX. Between the board and radio, TX goes to RX and vice-versa. If TX and RX are swapped, you won't damage anything, it just won't work. The supplied cable was already wired properly in my case.

To use the direct USB connect to computer instead ... leave the computer's radio disconnected. Pick the other com-port and set port speed back to 115200. I don't have to disconnect the Nova's radio. It doesn't seem to care if it's powered-up. It's ok to use the Auto com-port setting in MP if you need to.

Telemetry radios sets come in 915mhz or 433mhz. You should probably get the correct frequency for your country. Power should be left at max or 100mW (MilliWatts).

The clones (HobbyKing and generic Chinese) of 3D-Robotics Flight-Controllers and connecting sub-devices tend to use Molex PicoBlade 53047 Series connectors, while devices and cables purchased directly from 3D-Robotics use Hirose DF-13 Series connectors (to match the Hirose plugs on genuine 3DRobotics Flight-Controllers). Both are 1.25mm pin-spacing but are slightly different otherwise. The plastic connector-housing is shaped a bit different. Additionally, the Hirose DF13 pins themselves are square-ish, while the PicoBlade pins are rectangular/flat like "blades".  This makes the male and female pins incompatible in my book. I personally would not mix any parts of the two connector types. Instead, I would build or buy the proper cable.

The idea for this mod. is based on this blog article. Many thanks to Jean-Louis Naudin. However, I highly suggest you take the time to solder-in the PicoBlade connector.

With the release of (custom-compiled) Special CX-20 APM252 version of ArduCopter v3.1.5, there is now really no reason for anyone to attempt to do DogDude's (risky) originally popular "Resistor Hack" mod. Install the Molex PicoBlade connector and run an appropriate version of custom ArduCopter.

ArduCopter Versions that Support Telemetry on this APM_252

I guess what it comes down to is that this Cheerson APM_252 Flight Controller requires some special ArduCopter code for the Telemetry/Uart port to work properly in the Nova and CX-20. The common/public versions do not have the special tweak, so you have to run a version that has been custom compiled.

Here are the various versions that I know about:

ArduCopter v3.1.2 (Special CX-20 APM252 version). It's only available pre-loaded from factory (no way to download it if it ever gets erased). This still appears to be the "shipping version". Pretty stable code and should fly your quad fine at first.

ArduCopter v3.1.5 (Custom CX-20 APM252 version). Last stable release of 3.1.x based code. Still has Terminal and this simpler ArduCopter code seems to run good on this tiny processor. This is what I run now on this quad's Flight-Controller. Many thanks to VinnieRC.

http://www.rcgroups.com/forums/showpost.php?p=31678509&postcount=24678

ArduCopter v3.2 (Custom CX-20 APM252 version). Reportedly, you can also successfully run this Custom Compiled Firmware if you wish (Thanks to Frank/ Funtastix). Code is more complex and Terminal has been removed. Watch your Logging level (due to processor over-head) and PM-LongLoops.

http://ardupilot.com/forum/viewtopic.php?t=9534&p=22723#p28709

Cheerson APM_252_5.0 PCBs (Update Feb. 2015)

According to RCGroups Forum reports, this mod works with both v2.0 and v5.0 PCBs in CX-20 APM252 FlightControllers. What I have been calling "Telemetry Port", Cheerson/HK is now calling "Uart port" ... it's the same port. Version 5.0 boards not only have Molex PicoBlade socket pre-soldered-in for Uart port, they also have ADC Port for easy PowerModule connection. So, these APM_v252_v5.0 boards have the following connectors soldered in:
UART (Telemetry) : 5 pin Molex PicoBlade
I2C (Compass/Magnetometer) : 4 pin Molex PicoBlade
ADC (Power Module) : 3 pin Molex Pico-Blade

While Cheerson has added Uart PicoPlade sockets on v5.0 PCBs (so you don't have to solder-in your own), they might be soldered in backwards. If using any pre-made cables, be sure main voltage is on correct pins (VCC polarity), or you will destroy Telemetry radio module instantly. You do this by verifying voltage polarity on Uart pins with a volt-meter before connecting cable. Also, you can try swapping TX-RX wires if no communication after trying everything else (only TX-and-RX wires can be swapped without fear of damaging anything).

Troubleshooting:
For example, telemetry radio just randomly disconnects and re-connects. These are listed in most-common problem order first.

Be sure Settings match in both radios. Try the default settings. Baud Rate should usually be 57 (57,600) at normal distances. You do this from a laptop. I wouldn't deviate from these settings much, but if you know what you are doing, here are some details on Advanced Settings , and also this page.

The default for ECC is ON. While it is 50% slower (due to the over-head of error-checking code), several docs say it is "highly recommended" and they also mention longer ranges.

The first time you get it working should be from Windows computer running MissionPlanner (other radio on quad).

These 915mhz v2 radios have very good range and Frequency Hopping Spread Spectrum (FHSS). I have seen them reach 0.5 mile easily, and they likely go further than that. If there is a lot of multi-rotor activity around you, try changing the Channel (aka Net-ID).

If you are using DroidPlanner (on Android device and with USB-OTG cable), instead try a Windows laptop, MissionPlanner, and a different cable. See where problem follows. Also, vice-versa (if you normally use MP, try DP).

Try to observe power lights on radios to make sure you don't have a power problem and/or a simple cable problem. USB cables (especially the smaller form-factor ones are historically not durable).

While I use MissionPlanner, here is a tutorial using APM Planner and what appear to be a bundled 3DR RadioConfig. Nice graph might be helpful in troubleshooting.

Flight #4

At neighborhood rec field. Winds 15mph with higher gusting (so "windy"). Just my weekly flight (nothing really special). I stopped flying at 8 minutes before LowVoltageAlarm kicked in.

Before going to the field, I downloaded my log files to laptop for later analyzing. I also added a sticker to the outside of the Nova with my contact info (in case of fly-away or lost after crash).

During a RTL (final descent), quad was at 3 feet altitude when a strong gust of wind hit. I think the "Ground Effect" had started and wasn't helping. The Nova started rocking a lot and it was trying to compensate and level itself. It touched down (fairly soft but tilted) but still flipped over upside down (I think a prop got caught on a vine). No damage.

Because of this event, I think the quad needs more response at FlightController level (when it's in control of itself). As my piloting skills and confidence level with this aircraft have progressed ... I am also ready for a bit more control or "higher rates" for fighting the wind or general maneuvers.

I changed ANGLE_MAX - this determines the maximum "tilt" that the FC will command the Nova. I changed it from the factory setting of 2200 (22 degrees) to 3000 (30 degrees) to give the Nova a bit more response-ability when flying in the wind.

Flight #3 - Another good flight

Third flight and third new flying site. Today we are at the park in a secluded field. Only non-ideal attribute is there is a power-wire hanging-down in about 2/3 of it (but easily avoided). Winds were 12-18mph. Flew my little v262 quad to warm-up and then let my brother fly the rest of v262 battery (he's a new RC pilot).

Flew some simple patterns and used Loiter-Mode. Loiter was holding good and re-positioning after wind-gusts. All good there. Noticed I can also Pitch, Roll and/or Yaw in Loiter and it then holds at final position ... nice.

Tested RTL Mode for the first time. Worked fine and landed better than me (without tipping over). This is even more amazing to me than Loiter. Tried it a couple of times with success. Noticed you can even switch directly from Loiter to RTL with no problems.

Only had one problem. Incidentally, this was really the first time I've seen the Nova do something un-expected. However, it was the very end of flight/battery and the LowVoltageAlarm was activated (for about a minute already) so I'm going to chalk-it-up to a low battery for now.

This is the event:

Loiter Mode - Good and Holding (fairly high)
Nova activates LVA - Light Flashing and Beeping
Switched on RTL - In hind-sight not smart of me
Gaining a little altitude and moving above RTL point
Reaches position and starts to descend (but slowly as usual in RTL)
Taking a while to descend and fighting wind
About a minute now in LVA - Beeping is getting faster (a bad sign)
About 20 ft off of ground
Suddenly, Nova rolls (banks) off fast in aft-port direction
Couldn't tell if it was flying-off or just trying to crash
I switched to Stabilize (manual) and made an emergency landing on edge of field
No damage. A little too exciting. Battery reads 10.4 volts.

Another good day. Lesson learned is ... when Nova's LVA engages (I think it's at 10.6volts) land immediately ... you are running on LiPo fumes. Also, probably not a good time to purposely engage RTL.

I have pics (so yes, it DID HAPPEN :-) but they are still on my brother's phone.

Flight #2 - AutoTrim done

I did the AutoTrim procedure. This way, the quad's FC (FlightController) can benefit from Trims also (not just RC operator with "trimed" TX).

http://copter.ardupilot.com/wiki/autotrim/

Removed Trims applied at radio (during the first flight) and put everything back at 0 or neutral. I recommend you be directly behind the quad, facing the wind. Actually, there should be no wind.

No problem getting into AutoTrim calibration Mode (just hold stick a while longer than required for Arming). If it doesn't work in Loiter Mode, try Stabilize. Red (and tiny yellow) lights will dual-strobe-flash when you enter mode. Only catch is that you have to take-off (with a likely out-of-trim quad) and hold a nice hover for the next 20 seconds. Lights will stop flashing signaling the end of the test period. Land the Nova and disarm to save new generated AutoTrim settings. It's only my second flight, so it took a couple of tries, but I got it done. Takes off and flies much better now (even in a little wind).

Summary: With AutoTrim the roll and pitch trim are captured as you fly in a stable hover.

1. Find a wind free environment with sufficient space to fly your copter without crashing into something. Be sure radio trims are reset to zero or neutral.

2. On Mode-2 transmitter, hold throttle stick down and right for 15 seconds or until you see the small red and yellow leds (behind Arming lens) strobe-flash in a cyclic pattern. Action is like Arming except holding longer.

3. In Stabilize mode, fly your copter for about 25 seconds in a stable hover. IIRC, red/yellow leds stop flashing in flight.

4. Land and put your throttle to zero and wait for a few seconds (the trims are being saved to eeprom). Nova will dis-arm itself.

5. Take off again in Stabilize mode and check if your copter is flying level now. If not repeat steps.

Also, I got to try Loiter Mode for the first time. Worked fine. One of the coolest things I've ever seen one of my RC models do over the years. While Loitering, I quickly took this pic with my iPhone (I know, pretty blurry).

If you are having trouble arming quad, here is a summary: If you have GPS-3D Lock (rear green led is On-steady), AND hdop <= 2.0 ... you can (and should) Arm in Loiter switch mode. Then, switch to Stabilize Mode and take-off. Otherwise, you can just Arm in Stabilize Mode ... but don't expect RTL (pilot invoked or emergency) to work during that flight. Also, don't switch to and try to use any GPS dependent modes like Loiter during that flight.

It was getting dark, but was fairly easy to see whole quad (actual direction orientation ... not so much). Good flight and got in some good practice. Pretty boring flying, but I'm getting more confident with it.

AutoTrim Notes:
While flying normally, you can trim on radio sticks if you must (temporarily to keep from crashing). But to do a proper Auto-Trim, they should be neutralized or centered first. Also, remember that Trimming due to wind forces is counter-productive because you might be pointing in a different direction later in flight. Instead, that's why we have Loiter mode.

If you enable Auto-Trim and do it poorly, the next time you take-off, quad will be out-of-trim. You can either do it again until you get it right. Or, you can use Mission Planner to reset the Trim-Defaults with the following parameters:
AHRS_TRIM_X,0
AHRS_TRIM_Y,0
AHRS_TRIM_Z,0

Auto-Trim is often required because quad's CoG is slightly off, but I think there might be other reasons. Good pilots have been know to accomplish an AutoTrim procedure in their garages (because no-wind is important), but you will have to get it pretty high to avoid the "ground effect". Also remember that concrete and shelves are hard and cars scratch easy (you have been warned) :-)

More Parameters

Checked some more parameters (suggested in Nova forums). All the parameters are at MissionPlanner/Config-Tuning/Full Parameter List/ . After you change some, click the Write button and wait 10 seconds (to save them to FC internal memory). You can also click Save button to save them to a computer file. I usually do this before and after changing parameters. So that I can have them all in one place, here are some others (some changed after 4th flight). This list has basically become what I am currently running on Nova quad in 2014  Feb 2015.

ANGLE_MAX = 3000 (default 2200)
- This determines the maximum "tilt" that the FC will command the Nova. I changed it to 3000 (30 degrees) to give the Nova a bit more response-ability when flying in the wind. Works in manual flight-modes like Stabilize and also modes like Loiter. Some pilots set it even higher (like 3500).

LAND_SPEED = 30 (default 50)
- Slows the landing speed for RTL and Land. It's suppose to help with tip-overs on auto-landings.

LOG_BITMASK = 830 (Default)
- Default logs enabled: ATTITUDE_MED GPS PM CTUN NTUN CMD CURRENT

LOG_BITMASK = 958 (Default + IMU [vibrations])
ATTITUDE_MED GPS PM CTUN NTUN IMU CMD CURRENT

LOG_BITMASK = 26622 (Almost all. A full diagnostic set used in trouble-shooting)
ATTITUDE_MED GPS PM CTUN NTUN RCIN IMU CMD CURRENT RCOUT COMPASS

PILOT_VELZ_MAX = 250 (default 250)
- The maximum vertical velocity the pilot may request in cm/s

RTL_ALT = 2000 (default 1500)
- On RTL, quad will climb to this altitude (2000 = 20 meters or about 60 feet) before heading home. I think this should be high enough to miss any trees and houses (for now).

THR_MID = 575 (default 500)
[Now with Mobius camera, stock vibration-dampened camera-mount, 915Mhz Telemetry radio.
AuW with 2700mah battery is 1002g]
- Used between manual-control and other Flight Mode transitions. Not noticing any major altitude changes when switching between Stabilize and Loiter mode. But for the quad at it's stock weight (no attachments or payload) 500 was good then.

WP_YAW_BEHAVIOR = 1 (default 0)
- This determines which way the craft points when flying a mission in auto mode (or RTL). The factory setting of 0 doesn't yaw (turn) the craft when moving from waypoint to waypoint. 1 is so that it points the front of the craft in the direction of the next waypoint. 2 is the same as 1 except not even for RTL.

Others that should already be set correctly by default (in default Nova param file), but you might want to double-check anyway:
COMPASS_EXTERNAL,0
MOT_SPIN_ARMED,0
THR_MAX,1000

Extended Tuning Parameters from Feb 2015 (AC 3.1.2)
PIDs should still be same as stock Nova defaults

ESC Calibration

Apparently, on the PnF model ... the ESCs are not calibrated at factory. This might be because a radio is not installed until owner receives it. I figure, better safe than sorry ... so I researched it.

http://copter.ardupilot.com/wiki/initial-setup/esc-motor/#All_at_once_calibration

Just a reminder that the steps in this blog are presented in the proper chronological order. For instance ... the radio system (and other sensors) should already be properly calibrated in MissionPlanner before attempting this. Likewise, parameters like THR_MAX,1000 should already be set. However, PC should not be connected for this procedure.

Procedure seems to work, but the tones and led flashing are a little different than the posted "all at once" YouTube video (I think since he had full-APM Flight-Controller). If you look closely behind the Red Arming-Light Lens on the Nova, you will see there is actually 2 tiny leds behind it (a red one, and a yellow one). When they both flash (I call it a strobe effect) it indicates you have entered a calibration-mode ... one that you initiated with TX and quad (as opposed to one from MissionPlanner). In this case it's the ESC (All-at-Once) Calibration Mode,

http://www.youtube.com/watch?v=gYoknRObfOg

Also, he is using Mode-1 radio, while most of us here in the USA are flying Mode-2 (throttle on left). As the video shows, you enter this mode by holding the (Mode-2) Throttle (left stick) down and to the right ... like you are Arming, but much longer.

Nova ESC Calibration Summary (with FrSky radio set):

1. Start with Nova's props removed and lipo battery disconnected.
2. Turn on TX and move throttle to Full.
3. Switch to Stabilize Mode on TX.
4. Connect Nova main lipo battery
5. Red/yellow leds behind Arming lens will strobe-flash
6. Unplug Nova lipo, wait 3 secs, then plug back in (leave TX Throttle on Full)
7. Nova's red/yellow leds behind Arming lens should again be strobe-flashing
8. Fairly quickly (within 1.5 secs) move Throttle stick to OFF (or bottom of throw)
9. Nova will beep 3 times (2 short, 1 long) signally this step is complete (with v1.0 ESCs)
1. With v1.6 ESCs, you might get an extra 4 beeps in the beginning, but not with v1.0 ESC IIRC.
10. You should now test throttle and get an even response from all 4 motors.
11. Unplug main lipo battery, wait a few seconds, and then reconnect it.
12. Now arm the motors (with right rudder/low throttle for 4 secs). 
13. All your motors should spin if given a little throttle.
14. Your ESC's are now calibrated. No further action is required.

I can't think of a good reason to have motors spin on arming (and several good reasons NOT to), so I then went to:
MissionPlanner / Config & Tuning / Standard Parameters / ...
and set the parameter "MOT_SPIN_ARMED" to "Do Not Spin".
The parameter had a null or empty value at first. Strangely, I had to set it and write it several times before it took effect. Anyway, it works properly now (even after power on/off cycle). A related parameter is THR_MIN, but I left it unmodified.

Motor Test is not required for successful ESC calibration, but it certainly would not hurt to do it. They should all spin and sound about the same. I test motors from MissionPlanner/Terminal (type "test", then "motors"). It will start at Motor#1 [M1] (aka Fore-Starboard Motor) but instead of following the true X4 diagonal-like M# pattern, it will instead ... proceed Clockwise around quad (so it's M1, M4, M2, M3).

When I power up my Nova with LiPo battery, mine always plays (a kinda musical) series of tones or beeps ... short-short-short-(pause)-long. This is with four stock v1.0 ESCs and the 3S-LiPo.
Stock-white Radio Note 1: I don't have one (or have ever held one), but according to forum posts, the ESC calibration with "stock white radio set" is a little different due to the way the TX & RX Bind together on power-cycle. Some say to use a temporary 5v power source (likely a battery) to keep on-board RX powered-up during entire procedure. Or, you can try this way-1 (direct-link) or this way-2 . Finally, Mr.Jagger in forums says this version #3 is best. Be sure to find one that actually works and "settings take".

Stock-white Radio Note 2: True APM Modes and comparable (Nova-CX20 Mode): Stabilize (Manual), Loiter (Stable), Simple (Direction Locked), Altitude Hold (Altitude Hold), RTL (Return To Home). In my docs, I always use the true APM flight-mode-names.

Stock-white Radio Note 3 (using confusing Mode-names from Nova/CX20 Owner's Manual): If you are having trouble Arming quad, here is a summary: If you have GPS-3D Lock (solid green light) AND hdop <= 2.0, you can (and should) Arm in Stable switch mode. Then, switch to Manual mode and take-off. Otherwise, you can just Arm in Manual mode ... but don't expect RTH (pilot invoked or emergency) to work during that flight. Also, don't switch to and try to use any GPS dependent modes like Stable during that flight.