Aftermarket Hot shoe wiring question

Hi Emlid team and all friends.
I try to utilized my Reach + Pixhawk / PPK mapping setup for helping friends (Surveyors). Is not an easy way for me to start because of my background, only a drone hobbyist.

I follow all resources from Emlid and Tuffwing web already. but facing some problems. question :slight_smile:

I use hot shoe aftermarket like this:

I cut the end-plug and replace it with 2 RC Leads: the Positive to Reach Time-mark + Negative to Reach Ground, and Second Lead to Pixhawk pin 54 (Geotag) only, No Ground pluged.

Is that format Correct/ will Works?
We already did some experiment (no fly - walk only) and did some shots. when we read the result, the Path is far from accurate. We will try again of course, after get some guidance from this forum.

Any input will be appreciated. Thank you very much!
best regards

Hi @G-Boediman,

I’d highly recommend you to connect PixHawk to the ground as well.

May I ask you to clarify what’s the accuracy you get?

Hi, Tatiana.
thankyou for your input.
this is my latest rover test. (+base)
TOOLS: Emlid-reach (rover + base), pixhawk, Futaba for trigger >Sony.

Tatiana, now the PATH is good, correct by the way. Im happy w/ the result.

My questions:

  1. Is that correct, the time mark displayed created by cam trig from hot-shoe?
  2. is there any other way to make sure my hot-shoe sent a signal to reach module?

Thank you for your guide and help.
*next I will process log data from Pixhawk

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Hi @G-Boediman,

Glad to hear you’ve got good results!

Do you mean “Last time mark” field in ReachView Camera Control tab?
Every time Reach records an event, Last time mark value is updated.

Hi Tatiana
sorry for late reply - did some test again this weeke ends*

My question was about the TIME MArk on that RED square - I think that is not generate by my cam trigger. isn’t it?

Hi Tatiana and friends
below are my last test.
comparison Reach emlid result vs unfixed Pixhawk path (path without number is REACH)

my concern still on cam trig/ Time mark/ Cam feedback things, it seems not work yet.

the close up

The path without TIME mark, isnt it?
I wonder where did I go wrong.


  1. wiring - loose
  2. no signal from hot shoe

other thing is: on Mission Planner. The Green circle Camera icon from cam_feedback activity was only pop-up once, suppose to be multiple, right? and from the Message window, shown that the fast trigger capture text, also appear only once.

I need suggestion from you, and friends :

  1. How to TEST/ make sure the hotshoe send a signal to time mark and is injected to Reach GPS? - before we start real mission.
  2. Is the Photo capture Icon on the MissionPlanner appear only 1 (one) due to error on signal from Hotshoe to Pixhawk log? (photos below)

Any advice will be appreciated. Thank you very much Tatiana and friends.


NOTE: 10K resistor added to the hot shoe probably is the missing key will try this soon

Dear all, I have NO LUCK.
wiring set up:
Hot shoe = (+) split to AUX port 4 and 5 Volt/ Vcc, for (-) to Ground pin of AUX 4
the back rail on PX already 5V powered

No sign of voltage drop from 5.2V when I triggered the A6000
But if I push the TEST Button on the hot-shoe, the power drop as expected (to 3.2V ish)

dont know what to do next- will start from beginning again with new wiring.

Do you have Reach or Reach M+?

With Reach M+ ans Sony camera you can use this cable:

Hi Dmitriy
I have a Reach module

I just read the forum again - and some from DIYdrones forum too: have some questions:
1. which is correct:
A. PX shutter pin 55 to A6000. and the hot shoe (+) to time mark (-) to ground of REACH
B. same as above but split the wire from the hot shoe to AUX4 too (cam_feedback pin) with 10K resistor

2. why some use 1K or 10K resistor on 5V /Vcc wire of hotshoe that goes to aux4?
3. is there any test that can make sure the time mark on REACH is working properly? (before we download the log)

thankyou very much Dmitriy, for your help

Did some test again, but the BASE suddenly restart for several times. The path should be longer than that.
The wiring I made more simple, from hotshoe no split to Pixhawk. only to Reach.

some progres I think. the TIME mark file is there now. (.pos + .events.pos)

Will try another walk photo session with rather geometric path and make sure the BASE is always ON.

Hi @G-Boediman,

Have you had a chance to run another test? Was the events.pos file created with new logs?

Hi Tatiana
yes i did 2 very small test just to make sure the is there …and good Lord, they are in the result folder.
The Time mark/ cam trig DOT quantities on the map (PLOT) also shows the same number (10 x trigging) as the JPG files. So far we are happy.
The test was done in front of my class (yes, im an Art Teacher :slight_smile: ), cloudy and lots of tress.*
Next we will go to field to test in open space and good weather. also will test with split cable to AUX pin 53 Cam_feedback.
Is rainy season now - 2 weeks cant fly the UAV.
will be back soon with more good result!
Thank you Tatiana.

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My last test - real fly with hexa - thank all!
i’m happy now.
Time marks : confirmed

and the path -

If you have any input/ advise, will be appreciated.


Great! Thanks for the update!

@dmitriy.ershov sorry before closing:

1. in my understanding, range correction between rover and base RTK methode is limited to theire RADIO telemetry unit, correct?

2. How about in PPK, how far is the Base range can reach for the best result? my friend can not find the answer any where. are we misunderstand how the PPK works?

thankyou very much for help

Hi @G-Boediman,

We don’t recommend providing the baseline that exceeds 10 km in RTK and 50 km in PPK.

THANKKKK You for the info Ma’am - :grinning:
my team is very assured now

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