Good day guys !!  

I feel the need to obtain the information from my PixHawk in my Graupner MZ-24 screen. I found
some threads talking about a change in arducopter firmware to run the telemetry, not good at messing original controller firmware.

Then I found an "adapter" that staff of the AutoQuad made to convert the MavLink in Hott telemetry.

I come here to share a few changes I made in the project Mav2Rott downloaded here:
This is an adaptation to send the telemetry PixHawk for Graupner Hott Protocol.

Is correct with some features:

Battery Voltage;
Altitude for barometer;
Satellite count Speed;
Flight Modes Current drawn by the motor;
Direction of the Head;

I am not able to make it work:

Correct display Latitude and Longitude;
Distance of Home;
Direction of Home;

If anyone can help thank you very much.
The project is attached to the topic. The connections are equal to the jd-ioboard. I am using an Arduino Pro Mini.

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      • Newer version of MAVLink2HoTT converter is ready. Now it uses only PIN3 as HoTT serial is now asyncronous and fully interrupt-driven. This eliminates sensor data loss for several seconds problem present in previous version.

        Newer version 1.3 is to come soon. It supports Graupner Air Esc (S3032 & S3042) sensor emulation and is configurable from RC.



        • I tried you code with a Mini Pro and MC32.

          GPS, voltage, vario, flightmodes work.

          I use a voltage and current sensor, both are shown in Mission Planner but not in HOTT.

          Of course mAh used and so on can''t be shown too.

          Heading is shown as soon I have a GPS lock, but more precise and fast would be the heading created by the internal/external compass?

          Are these things not yet well implemented because of the missing Air Esc?

          As I have some HOTT values, my setup seems to work.

          BTW, the MC32 and GR16 are both on newest firmware, the Pixhawk2 runs with latest Firmware too, configuration is hexa.

          Very nice work Michel since now!

          For those who are afraid using a 5V input signal:

          With mentioned 1,5k resistance it seems to work.

          I used a 3,3V Arduino Pro before and, for some reason I did not research, it don't work.

          Maibe input signal from Pixhawk is too high, but as written, you can use a 5V input to receiver with the resistor without problems.

          • Thanks for testing!

            I only have MX-16 and MX-20 RCs and your MC-32 experience is important.

            I wonder why you don't have voltage and current data. I do have them.

            Don't be afraid of 5V boards. I use it without any resistors and it works fine. Just direct connection between PIN3 and HoTT telemetry pin. Please note, this firmware should work on 5V 16MHz boards ONLY.

            On heading display: now it shows flight direction, not heading and it's available only with GPS lock.

            Do you think it should show heading instead? Do you think it should be configurable?

            If possible, test please, auto mode with waypoint heading and distance display.

            In AUTO it should show direction and distance to current WP in home field. A "W" and "P" chars are shown right to home and WP number in last string right to flight mode.

            • You misunderstood me Michel, I have voltage displayed but no current, but I take a look at it this weekend.
              A real nice feature would be a voice advert when changing flightmode or WP reached.
              I started years ago an Atmel driven GPS and studied the HOTT protocol, I was not able fo find out how to generate a voice command.
              My workout was change the alarms and make a new voice file for MC32.

              About compass:

              With heading I mean true flight direction. :)
              But taken out from GPS data it is too slow for, let's say, navigation purposes.
              I'm am a nature and wildlife photographer, a copter or plane with IR-camera on board would be a very usable tool to scan a territory for animals at night, but a running monitor disturb the night sight of the eyes, that's the reason why I asked for a "real" compass.
              Such a night flight is far away from civilisation lights a resl IFR flight.
              Using LEDs is not always possible, some animals are very careful specially at night.

              I try it again over the weekend, I also recheck my port settings.
              • On voice messages: they are predefined by Graupner and kept in VDF files. You may download these voice packs for different languages from Graupner site.

                As I know there's no way nowadays to edit VDF file. I tried contacting Graupner, but they keep silence. If you know how to do it, let me know.

                Sensor or MAVLink2HoTT converter just sends voice msg number, and RC plays appropriate sound. There are 33 english voice messages as I found investigating my MX-20 RC. It's no problem triggering any message on WP pass or flight mode switch, but it won't contain correct text.

                About compass/GPS:

                Again I misunderstand you ;)  If you fly copter, not plane, then true flight direction cannot be obtained from compass as copter may fly any side forward. Though if you need TRUE FLIGHT DIRECTION which means movement vector, you only should rely on GPS as there's no other way to get it.

                If you need azimuth where nose of your aircraft points, you should only use compass.

                If you make night flights without any visual contact you may experience difficulties orienting aircraft in space and getting home. In this case you may use home distance and direction fields. Home direction is angle from aircraft nose and line from aircraft to home position. Eg. 180 means your copter is turned back to home and 0 means it points it's nose home.

                Please note, that in AUTO mode these fields show distance and direction to next WP instead.

                • The VDF Files are predefined, but you can easily replace the original voices using 2 programms called Bababolka and Goldwave, as said, replace, you cant add some new ones because there is a limited number of messsages which are generated by HOTT.

                  Voice quality is not the same, because the voice is generated out of Text to Speech, but still good to understand.

                  You do something for me, I do something for you.... If you want, I compile a VDF for you, only thing I need to know is which alarm number to are going to use to fire up the message.


                  NOW I got it, you are right, if I fly sideways I have wrong heading with true compass, I forgot its not a plane.

                  I put a prop on one engine right now to test the current data, HOTT show 2A at half throttle, I think it's a little too low, but I tell you more when I have a complete running system. One brandnew ESC seems to be defective, so I am not able to do a flight right now.

                  The mAH are not actualized, seems there is still remaining a little problem.

                  • First tests on ground!

                    Works PERFECTLY with MC32 and GR16!!

                    Very good work! You made my day Michel!

                    Rpm seems to be a little too low, i am sure that my slow running armed engines do more than 60 rpm.

                    The HOTT ESCs I own do the rpm calculation with number of poles which needed to be defined over the settings menu, maibe it's an idea for you.

                    I'll try a flight test as soon as rain stops for more than a few hours.....

                  • 1.3b is going to be tested tomorrow,  sorry Michel for late reply, i was out for vacations :)

                  • Version 1.3b available for testing and usage.

                    Get it here:

                • Some info about update speed:

                  GPS data is updated faster than HoTT screen. RC requests sensor data 3 times per second. It requests each sensor twice. If we are emulating 4 sensors (as in MAVLink2HoTT v1.2) all data is updated in 4 sensors * 2 times per sensor = 8 cycles. Each cycle lasts 1/3 second. In result we have complete info update in 2.7 seconds.

                  In version 1.3 there is feature to enable/disable each sensor emulation.

                  Using this feature user can select whether get slower update, but more information

                  or less information with faster update.

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