Inside my Model's cockpit...
As of 19th October 2011 – this material now transferred to NEW WEB SITE
Graupner (Germany) recently released a major new R/C technology based on spread spektrum frequency hopping and bi-directional data exchange/telemetry. This technology makes highly efficient use of the 2.4Ghz band and for the first time provides the modeller with an extensible and well integrated product suite that provides rock solid R/C control alongwith real-time data telemetry of a wide-range of ‘in-model’ parameters. This telemetry data is available via on screen displays as well as via audio and logged data. Sensors capture data for voltage, Amps, temperature, spatial location, vario and RPM etc. Ideal as a space saver, complexity reducer and as an invaluable flight data recording suite.
I chose Graupner HOTT as the basis for telemetry I will need on an Oktocopter that will carry out commercial tasks. I needed to omit solutions such as Eagle Tree (without OSD), keep the complexity low but the reliability and compactness high. Most of all I needed to restrict my RF frequency use to 2 bands max! – R/C and FPV video. Since I’ve made the choice I now have to build the radio, configure the settings and see how it shapes up in reality. Initial tests will be done with a Multiplex Mentor which I plan to fit with Feiyu Tech’s FY-30A IMU unit (Inertial stabilisation and attitude control).
Comments, concerns will be logged here; and for that reason (and because I’m not blogging all day), what you read here may not be up to date. I hope it may be of some service to those who adopt the technology later than I – if like me you are an inveterate early adopter of challenging technology and some of the manuals and firmware burns are still in draft then its indispensable to bounce ideas around and record issues in an accessible way.
Now before I make some specific points, I have to first understate the level of respect I have for the concept and technological creativity that underlies Graupner’s new technology stack. I understand that their MD Mr Graupner took great risks in investing in the research that was necessary for them to leapfrog the competition and set a high bar to attain (Probably why Futaba telemetry is so late – they’ve no doubt had to go revisit the drawing board). For this very reason immersion in HOTT IS NOT FOR THE FAINT HEARTED. Getting the most out of the sets will require a large amount of time buried in manuals and polling for the latest official Graupner HOTT video updates. There are plenty of instances where a fresh approach has been taken which may disconcert the old school. The challenge for Graupner is to explain the technology in such a way that one moves error free from the fundamentals through to the dazzling power of the advanced features, the favourite being – telemetry with voice output. We lessened the crashes due to poor flying technique by grabbing a flightsim now we can solve the next problem – avionics, that’ll leave force majeure which’ll just have to be down to my insurer or the many means there are of placating a partner. This is an awesome product but I need help!!
Added 13th October 2011:
Here’s a link to a schematic of a representative HOTT setup (My current state of knowledge)
CLICK IMAGE:
(Google Docs source)
Added from 12th October 2011 onward:
FIRMWARE UPDATE PROCEDURE
- Unlike most radio systems, Graupner HOTT is unique in that most components – except the sensors (exclude GPS/Vario here) are flashable. If you’ve ordered a set then you can be next to sure you will have to flash the firmware on everything. OK well that gives one a nice feeling – we know things can improve over time and whoever got something wrong can issue an update rather than send out a whole new piece of hardware. Only thing is that right now its a bit bitty, you need to string three wires/adaptors together and press this whilst you turn that on. I managed it but set aside 2 hours if you have a new set – be sure to look at Graupner’s videos first because this is not covered adequately in the manuals and there is no single method for all of the modules!!.
- Programming the new HOTT TXs is easy – you just need the PC software (which looks really neat), a mini USB cable and the firmware file.
HOTT TELEMETRY MODULES: TWINNING UP/DAISY CHAINING
- Page 117 of the MX-16 HOTT Tx manual says that you need the 12 channel Rx (the GR-24) to use more than one sensor module. I got one of these today but it only has one telemetry connector; OK so how do we connect the two sensors/modules and read them simultaneously? UPDATE 19th October 2011 : According to Graupner Germany (Via UK Agent): You will be able to attach two modules/sensors to the GR-24 via a Y-cable but as of today you need to switch between both in the Tx’s Telemetry settings in order to view their readings (not practical, nor of any use), i.e. right now one cannot view real-time data from e.g. A GPS/Vario module as well as the General Engine Module. THIS IS DUE TO BE FIXED VIA AN IMMINENT FIRMWARE UPDATE.
- Once we find out if its possible to use more than one telem. module with one Rx we then need to know A LOT ABOUT which modules can work together so for instance the General Engine and Air modules each measure Amps motor draw – what if I was needing to use two of these together to monitor the power in a hexacopter or octocopter – is this possible?
- What happens if I use the GPS Vario module with the Air module 33620 which has Vario in it?
- Why does the 33620 Air Module support RPM?
TX PROGRAMMING
- For the most part the Menu and logical layout of the MX-16 TX menus and progamming flow is truly excellent – BUT
- There is a really poor section and that is the ‘ Telemetry’, ‘Setting & Data View’, ‘General Airplane<>’, ‘> Set Warning’ Menu. Apart from it being 7 clicks out of the way (hard to find) its a bugger to program for one very important reason: Its not clear how to save the settings you make!!!! AAAARGH. I got it workoing but can’t even remember or work out how I got it to save. It seems a though the first thing you need to do is tell it you want any subsequent settings changed by using a wrongly named menu item called’SAVE > SENSOR Yes or No’. That is atrociously bad. As of 13th October 2011, this part of the ‘Setting & Data View’ Menu is missing from the Section starting on page 118 of the MX-16 Tx menu. Neither is it in the Appendix.
- The setting s for when a warning is sounded and for how long could be better explained/made clear
VOICE TRIGGER MENU
- Great feature but EEEEK its a bit scary to programme it.
- What the hell does ‘TRANSFER’ mean – its not explained in the Tx manual at all but seems to relate to parameters that are Tx and Rx based as opposed to module/sensor based – again needs clearing up.
SETTING THE CLOCK
- OK so we find out there’s a clock backed up by a CR battery so we are then compelled to go check the clock and reset it to local time.
- Wade thru the manual and the first thing we findout is that its programmable via the PC utility – OK but I want to modify it on the Tx
- OK so the current time (which to me is a BASIC SETTING) is displayed on the ‘Info disp’ screen and modifiable from same screen – not very intuitive
CHANGING STICK PHYSICS
- I wasn’t too comfortable with removing self-centralising from the left-hand (MODE 2) throttle control – the screw mounting seems flimsy adn clicked out of detente a couple of times. Once done it seemed fine…
As of 13th October 2011, the above concerns were forwarded to the Graupner UK: Gliders Distribution, Newark, Notts. As soon as there is a response I will update the various sections.
I am planning on doing some videos on this superb new technology from Graupner – as and when I get going, they will appear on the ‘
GraupNerd‘ YouTube Channel, meantime there’s a nice HD slow motion video of a flight over an Oxfordshire farm.
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Musings from a Technocrat 