Servers by jDrones

Adding and controlling a Samsung NX camera with the Pixhawk

(Alexander Thorp) #18


Thanks again for your help with this. I got a 10 pack of servo plugs from Amazon.

This evening, I spent some time considering camera settings, and how I want it to be set when flying. The manual for the camera is very long, and there is quite a bit of flexibility in the design of the camera, most of which will not be controllable by the Pixhawk. So, I have chosen to take photos in “Smart Mode - Landscape”, which seems most appropriate for aerial photography (still subjects).

I also experimented some more with the auto focus and camera triggering to see how it might be affected by the servo circuit. I have decided to set the camera for a single auto focus before taking a picture. When I connect the PLS and GND wires, I confirmed that the camera focuses on the subject before taking the picture, and thus there is no need to separately control the focusing prior to taking a shot. Also, it doesn’t matter how long I hold the PLS and GND wires together - it will only take one shot whether connected for a small fraction of a second or for several seconds. So, your suggested setting of 1 second should work just fine.

I was reading through a manual related to aerial photogrammetry software that I have, and it suggests that the orientation of the picture (i.e. portrait or landscape) may affect the processing of the photos. Landscape is recommended, and switching between landscape and portrait is not recommended. So, I will have to mount the camera on the drone so that it will take landscape photos in flight.

I’m excited to build the simple circuit you have so kindly explained to me.

I’ll keep you posted.


(James Mack) #19

If you want to do mapping, you probably want to set it to full manual. Manual focus, shutter, aperture. The manual focus will reduce shutter delay and give better GPS correlation. Manual aperture and shutter will give consistent exposure so the images will blend properly.

You almost certainly want to take photos in landscape mode. This is doubly true because you cover a wider swath of ground for better coverage during the flight.

I’d hardly call it a circuit at this point. More of a harness. It’s just connecting four wires together to make a single pair. :slight_smile:

(Alexander Thorp) #20

There is an option to set to manual. I like the idea of reducing shutter delay, and giving better GPS correlation. I’m not sure I know enough about aperture and shutter settings at the moment to be able to optimize these settings for aerial use. So, will require some experimentation and reading…

(James Mack) #21

Very true. I’m not a photographer so getting the right shutter settings is always an experiment. You can usually start in aperture priority mode and focus to let the camera estimate a shutter value for you.

Manual focus is more straightforward, of course. Focus at an object at the expected flight height, or just focus at infinity (good for anything over 100 feet or so).

(Alexander Thorp) #22


Not sure if you’ll get this message. It’s been a while. I’m trying to follow your instructions from April 23, and I’m stuck on how to map a free channel to the camera trigger.

I’m using a Pixhawk PX4, and I’m using Mission Planner 1.3.49. As for a radio I have a FlySky FS-T6, which is a 6 channel transmitter. Channels 1 through 4 are set up in the usual way, and Channel 5 is set to SWA on the transmitter, which flips between Stabilize and Auto flight modes. Channel 6 is available. Using the interface on the transmitter, I have set channel 6 to the SWB toggle, and I have confirmed in Mission Planner at Initial Setup>Radio Calibration that when I flip the switch, the radio signal varies appropriately.

But, the mapping…you have suggested to use channel 8, I would set the parameter “CH8_OPT” to 9. In this case, since I’m using a 6 channel transmitter, I don’t think I have channel 8 available, so I looked for the parameter “CH6_OPT”. But, I couldn’t find it. I found channels 7-12, but no channel 6. I must not be understanding things correctly.

Can you help me sort this out?


(James Mack) #23

@BigAl you’re not missing anything. This gets difficult without at least 7 channels. The easiest remedy is to get your hands on a 7+ channel transmitter.

Alternately, you could revisit using the Pololu RC switch mentioned above, and connect it to the CH6 output on the Pixhawk. The outputs of the switch would connect to the GND and PLS lines on the camera cable, and the input of the switch would connect to the CH6 output on the Pixhawk. Then you’d power the switch off a 3.3V supply, either the 3.3V available on the Pixhawk top panel connector or with a separate voltage regulator.

(lucamax) #24

Interesting discussion.
I have a Nx1100 and will use it for mapping in the next months .

To simplify things one option is to buy a commercial solution from Seagull , with the cable , Map-X and hot shoe adapter ,it is a complete turn key solution for 200 Euro , platform independent , you just need a RC PWM output .
I think I will go for it .

(James Mack) #25

The Seagull solutions look nice, I hadn’t seen those before. But why the MAP-X? Most of that functionality (GPS tagging, hot shoe interface) is built into the Pixhawk. It looks like the MAP2 would be a less expensive choice.

(Alexander Thorp) #26


Thanks again for your help. I’m still a little puzzled…I would very much appreciate your further explanation.

I had connected my camera trigger cable to a servo cable, and I was thinking that I could simply plug the servo cable into the Pixhawk CH6 output, and use the spare radio channel I have to control it for testing purposes. While in the air, taking photos, I wouldn’t need to control the camera manually, as I was under the impression that the Pixhawk might be used to automate the taking of photos at particular geographic points, by way of mission planning. Can I do this?

I would be happy to take and post some photos of what I’ve done, if it is not clear in my description.


(James Mack) #27

@BigAl the simple cable only works on relay outputs. CH6 is a servo output, which is a different signal that’s not compatible with the camera. You’d need to configure the Pixhawk per the Apr 23 post, and connect the cable to AUX5 port. That should trigger off auto mission items, though because you don’t have channels 7 or above, you won’t be able to trigger it manually for testing.

If you used the Seagull servo adapter linked in the post above, you could connect it to a servo output like CH6, which would allow you to test on the ground with the servo output configured, and in the air you could configure as a camera trigger to shutter autonomously. The simple cable we discussed earlier doesn’t have that flexibility, because it only connects to relay outputs.

(Alexander Thorp) #28


I’ve been mentally mixed up between AUX5/6 with CH5/6, and now I understand that AUX5 & AUX6 are auxiliary RELAY channels whereas CH5 & CH6 are the main SERVO channels for control by RC transmitter.

I’m not yet ready to invest in another transmitter, so I like the options of a) using the relay control to its full capability, or b) using the Pololu RC switch. The Seagull MAP2 solution is intriguing, but can you tell whether it requires that I obtain a transmitter with at least 7 channels?

I very much appreciate your mentoring with this.


(James Mack) #29

The Seagull unit is basically a Pololu unit that’s pre-wired and ready to go. The Pololu is functionally equivalent but more DIY. Both should work with just 6 channels.

Also note that AUX5 and AUX6 are just configurable outputs, and one function you can configure for them is a relay output. They are extra servo outputs by default, which is why the parameters are changed as above to enable the relay function.

(Alexander Thorp) #30

I’ve gone ahead and ordered the Pololu RC switch. Seems like it’ll do the job for me, allowing me to test on the ground, and shoot in flight, all in one. Thanks again.

(Alexander Thorp) #31


I’m getting closer and closer. I got the Pololu switch, and I’ve begun the soldering process. I’m using the header pins, thinking that I might choose to configure the switch differently for some other purpose in the future. I’m all set on the input side of the switch, but have questions on the output connections and how to get power.

As for the output connections to the camera, I’m thinking that the OUT pin on the output side of the Pololu would get connected to the PLS line on the camera shutter, and that the GND pin on the output side of the Pololu would get connected to the GND line on the camera shutter. Does that sound right?

As for supplying power to the switch, I am at more of a loss. I see on the top of the pixhawk an unused port labeled ADC 3.3V, but now reading that this is for power input to the Pixhawk. My son suggests I should use the I2C port, but I don’t know. We have the output of the I2C going into a splitter (1 in and 4 out) and only one of the outputs is presently used to connect the compass. Looks like there are many potential places to get 3.3V off the Pixhawk, but what do you recommend?


(Alexander Thorp) #32


I don’t want to be a nag, but would really appreciate your further input. I’m afraid this thread is so old that it isn’t seen by most users. I’m close to getting this off the ground again!

Thank you,

(James Mack) #33

@BigAl, it looks like the power on the I2C bus is 5V. And I can’t actually find any connectors external to the Pixhawk that are 3.3V for power. While it all might work off 5V, I’d probably play it safe and put a regulator in there. Something like the one below, installed off a 5V source (I2C would be great) and wired up to power the Pololu switch.

(Alexander Thorp) #34

Thank you so much for your help. I am a novice when it comes to design of electrical circuits.

I was thinking about an alternative - to use the jumper on the bottom of the Pololu switch, connecting VRC to VCC. But, I think you indicated previously that the voltage on the RC side is not continuous, but rather a series of pulses, so I suspect this is not a good solution.

The Pololu switch does indicate that the power source can be between 2.5 and 5.5 volts, so theoretically a 5V supply would be OK. But, does the voltage at OUT on the switch equal the input voltage supplied at VCC? Or, does the switch reduce the voltage to 3.3V? If the former, I agree with your idea to use a regulator. If the latter, maybe the regulator is unnecessary?

(James Mack) #35

VRC is the RC power supply, which is usually a solid 5V. Only the signal is pulsed. So it’'s also a good candidate for power.

I believe the Pololu switch will operate at the VCC you supply. So if you power it off 5V, it will signal at 5V. And if you power it off 3.3V, it will signal at 3.3V. But you could do a test to confirm that hypothesis.

I’d connect VRC to VCC via the jumper to power the Pololu switch off the 5V from the servo cable. With it all powered up and running, toggle channel 6 on the radio and measure the output voltage from the Pololu switch (don’t connect it to the camera yet, of course). If it switches 0-5V, then you’d want to add the 3.3V regulator (but undo the jumper first!). You don’t even need the Pixhawk for this test, just an R/C receiver and 5V battery or source to power it would be sufficient.

(Alexander Thorp) #36

You are great, James. I’ll give this a try, and will post my results.


(Alexander Thorp) #37


I was able to test the hypothesis, and you are correct. The output side voltage of the Pololu switch is the same voltage as the supplied on the input side. I tested this by using voltage from 3 AAA batteries (I could not figure out how to turn on the voltage out of the pixhawk on main RC channel 6 - what parameter do I need to change?).

So, I’ve gone ahead and ordered the regulators that you have suggested. Thanks.