RC, photos & tech


Aerial Mapping with a GoPro, APM 2.5 & FX-61

The Problem:

Google Map resolution isn't good enough.

The Solution:

Fit a downward facing GoPro camera to Phantom Fx-61 Flying wing, fly circuits with the GoPro taking still images photos every two seconds or so, post process in AgiSoft PhotoScan.

The advantage of creating a map stitched together from still photos as a 3D model means it can be rotated and viewed from any angle. The example below was created from a very quick flight and not even with a pre-programmed flight path. I mostly just flew manual circuits so credit due to the powerful software processing.



Aerial Map


Aerial Map from an angle


This image shows a zoomed in section of this map using Google Earth viewer. The low resolution makes it difficult to make out the details.

Google Earth sample



The same section but from the custom made map shows a lot more detail.

Custom Aerial Map zoomed in


The Equipment:

FX-61 Wing FX-61 Wing Internals

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Character Set Update – MinimOSD

The problem:

The on screen display (OSD) characters from the Hobbyking Minim OSD v1.1 appear garbled.

video and at seven minutes in he explains that both sides of the board need to be powered for the character update to work. I was thinking "what the hell, how is this not stated on the instructions page!"  Actually it is, right here in black and white. The point is, if your Minim OSD lights don't look like the picture below, the character set update probably ain't going to work.

minim OSD ready for character set update

minim OSD ready for character set update





APM Arducopter: Problem with Altitude Hold Solved

The problem:

As soon as I engage Altitude hold on my Arducopter Hexacopter, it shoots up instead of holding a nice steady altitude as expected.

The solution:

My throttle mid-point was not exactly at centre and when I engaged Altitude hold, the throttle stick becomes an altitude adjustment control as opposed to a throttle meaning relative to the centre position, if the stick is up, the Hex will rise. If the stick is below centre, it will fall. I analysed a logfile where I had been hovering in a nice stable position and found my throttle setting to be about 480. I thought this would have been close enough to the default (500) but apparently not because after adjusting THR_MID, the Hex hovered perfectly in position.

These URLs helped me identify and solve the problem:


Setting Failsafe on Arduplane & Futaba T10CAP


The Problem: Switching my Futaba T10CAP Tx off wasn't engaging RTL on my HKPilot Mega 2.5 controlled Phantom FX-61 flying wing. 

The solution: In this plane I'm using the Corona R8FA 2.4GHz Fasst Compatible Receiver for which the manual is found here. The failsafe functions of the APM board are defined here. By starting the APM Planner v2.0.0 and going to 'Initial Setup', 'Failsafe' you can see the values of the PWM signal the Rx sees from the Tx. In my case, at low throttle position I get 1096 value. Switching the Tx off the value jumps up to 1150.

Going into the Basic Menu on my Futaba Tx, then 'F/S' I found channel 3 failsafe was enabled and set to 20% so when the Rx lost signal from the Tx, the throttle was going up.




1.TX-failsafe feature: This method is to set failsafe on the FASST transmitter and has priority (works
on channel 3 only under FASST 7ch mode or on multiple-channels under FASST multi-channel mode)
while the receiver is working on, just like the FUTABA receivers

For the APM Failsafe function to work, I need the value to drop below 1000 (defined by the paramter 'THR_FS_VALUE') so I disabled the channel 3 F/S setting. Now the RX-Failsafe feature (if enabled) value will be set on Channel 3 one second after losing the link to the Tx. The value is set by following the procedure below. To get a value below 1000, I temporarily set the end point on my Tx for channel 3 to 140% which brings the throttle value down to 966. Set the Rx-Failsafe mode (as below) and then restore channel 3 endpoint to 100%.

2.RX-failsafe feature: Turn on FASST transmitter and turn on the CORONA 2.4GHz Spread Spectrum 

Receiver, put all the sticks and switches to where give the control inputs you want if the receiver looses
signal and Press the F/S button down for about 5 - 6 seconds while the Green LED light solid (Rx in
normal operation), then release the button. You will see the Red LED will flash for about 4 - 5 seconds.
(Note: The Red LED will FLASH high speed to indicate the RX-failsafe is turned on OR FLASH low
speed to indicate the RX-failsafe is turned off). If you press the F/S button a second time while the Red
LED is flashing, the receiver will change its RX-failsafe status (on / off),then the LED will return to
Green solid again. If you not press the F/S button .Nothing will be changed and the LED will return to
Green solid again. If you want to cancel the RX-failsafe feature (not just turn it off), you can do it by
binding the receiver again.



Firmware Upload HKPilot Mega V2.5 Flight Controller

The first time I tried to upload the ArduCopter firmware to the Hobbyking HKPilot Mega V2.5 Flight Controller I got an error "Communication Error - no connection". Even though I specified the correct COM port identified via the Computer Management in Windows  7. Under the "Ports (COM & LPT)" it shows up as "Arduino Mega 2560 (COM35)" along with two others "Standard Serial over Bluetooth link".

Mission Planner 1.2.93 build 1.1.5131.36508_2014-02-02_21-23-15






Convinced I had the settings right I was beginning to wonder if I had a dud board. The solution I found was to disable the other two COM ports in the Computer Management.

Computer Management_2014-02-02_21-33-59





After disabling these COM ports, the firmware uploaded to the board with no errors.