Hi,
Have been working on an OSD compatible with MinimOSD, but based on a STM32F4. The OSD can do vector graphics and also can send data to the ground station using the unused frames after the Vsync pulses ( like teletext).( I use this to send data to my antenna tracker.) The OSD is desigtned to be a drop in replacement for MinimOSD and accepts Mavlink data. Also has 2 audio channels ( so can be used e.g fo vario) and various peripherals ( serial port, i2C, SPI and PWM capture etc,) broken out on headers.
Here is a video of the prototype working
regards
Andy
Replies
Really interested in this project! Been thinking about doing the same thing with an stm32 board I'd made but you've beaten me to it!
I'm actually based in Portsmouth.. You seem near?
@Gareth,
Hi,
I'm based North West of London, you are lucky to live on the south coast :)
Is your board an OSD board? If it's open source I am always interested in OSD hardware.
I have actually moved more to focus on combining the OSD and Flight controller now on a single board, rather than a MinimOSD replacement, since I found the STM32F4 is quite capable:
http://diydrones.com/profiles/blogs/ardupilot-flight-controller-wit...
regards
Andy
And yes, the card works with Arducopter also. I have built up a V2.1 board (thanks to Andy for providing a blank PCB) and added some new symbology parameters. My version is heavily text based right now, but the OSD will allow for nicer graphics to be added (like Andy's compass). Shouldn't be any issue running this with Arduplane - just need to change the flight mode strings and enable the airspeed parameter display (only GPS speed enabled in this video).
I didn't have any GPS issues with this version, but did have the OSD under my DJI X550 frame and the GPS is on the top above the controller so did have some distance between them.
Looking good and nice to see the board working in NTSC mode
The V2.1 board is definitely not bad at all from a GPS point of view and is also slightly easier to build than V1, therefore I have removed the V1 board from OSHPark and replaced it there with the V2.1 board.
https://oshpark.com/shared_projects/yiU4RsLa
The OSHPark page has links to the schematics, source and a Bill Of Materials too.
regards
Andy
I have actually got a micropython board and it seems quite easy to use, though not done much with it. In terms of programming the OSD in Python. I think it would realistic to get a python API. Though Python is pretty slow, It should be quite efficient too since the Python interpreter is only at the highest level and most of the grunt would still be C++.
Its another path for the OSD waiting to be explored. :)
regards
Andy
Hi Colin,
I would think that object recognition is some way down the road! But its a fascinating project
regards
Andy
Managed to get the FixedWing maiden of the OSD today..
Telemetry for the tracker is working via Video Audio and FrSky telemetry RX, Need to adjust artificial horizon pitch, but can do so via flash variables for next time. so Next task is to get the video vsync telemetry working, which will make the Audio telemetry redundant pretty much , though has been fun to experiment with software FSK modem on the STM32. Also looking forward to pulling in Andrew Fernies work on switching screens etc on Github...
Hi Julian,
I need to verify with my co-conspirators, but currently I am still not really happy with the board. I have a feeling there is a lot of RF junk coming off it. Its certainly an order of magnitude better than V1 but there are still many things I would like to try:
-Different board shape. As it stands it looks like the board may be just right to act as a 1575 MHz patch (GPS frequency) I plan to copy the BrainFPV/OpenPilot board dimensions and see if that changes things. That said V2.1 board is an order of magnitude better than V1, defnitely flyable as shown by the vid
-Better EMI rf filters on power i/os e.g bead inductors etc. There are definite issues with this still. You need to try different placements. presumably where they cancel.
- Maybe a rf shield case. This might be as simple as a cardboard wrapper with some aluminium foil around it( I'm thinking FrSky D4R-II style). Having only had one flight its difficult to be sure but think my video range is down a bit. so may be due to rf from the OSD
All that said, the board works as can be seen so I see it currently as a hackers board. It has loads of untapped potential. One major goal is to plonk the whole APM stack in to it under the OSD. If it runs on a 16 MHz Arduino, this should be no problem ( and clearly works as shown by BrainFPV).
I will make the V2.1 board( as shown in the vid) available on OSHPark shortly. If you are still reading, I will see if can make some sort of kit of parts available. I think the (small quantity) parts cost to me is around $40 - $45. So bearing in mind the above, if you are intersetsed lete me know and I'll make a parts kit up... Soldering the board would not be a job for a novice though..
I hope to get on and design a new board version shortly but there is now a long list so may just live with V2.1 for a while and concentrate on the user side stuff
regards
Andy
As an update on the subject of rf interference. I managed to get a friend to do some frequency scanning.
On the V2.1 board( with its aluminium foil screen/package) there is a small amount of noise at 1560 Mhz which might explain the slightly reduced GPS sensitivity. This is in contrast to the V1 board, which has a largeish noise spike at exactly at 1575 MHz ( GPS frequency), which explains why the V1 board was so effective at jamming GPS at up to 1m away. Unlucky in some ways but has forced me to learn about RF issues and the resulting V2.1 board was much improved.
Overall I dont think the V2 board is bad at all . Its certainly flyable. In fact here is a video of me flying out to 2km + on my 25 mW 5.8 GHz system...
which is a personal best for me with thiis set up..so this is quite good proof that noise is quite low at 5.8 GHz and 2.4 GHz.
Despite this we are going to have a go at removing the last issues at GPS frequencies so planning to design another pcb yet...
regards
Andy
Hi,
Just a heads up.
Have found a major problem with the V1 PCB. It seems to act as a perfect GPS transmitter and jams my UBLOX-LEA6H at 0.5 m or less.
I'm looking into the issue, but ultimately this is going to require a new PCB to solve. I need to pay much more attention to rf layout clearly.
Apart from that the PCB is working very nicely. Crystal clear and crisp, but not much good without GPS :)
regards
Andy
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